I'm embarking on a long term project to update the electrical system, both chassis and house for my newly purchased 2004 4020. This thread is going to be a work in progress as I figure things out.
My goals for the updates to the bus:
- New chassis battery and better charging for them.
- New house batteries and better charging.
- Inverter/Charger installation.
- Solar.
Others have done similar projects, so I plan to read any of those threads in this forum. There is a lot that I still don't know about my coach, so I welcome the feedback from others.
1 - I'm starting with the replacement of the chassis batteries.
Here is what I know so far. The chassis batteries currently in the bus are 3 of the Duracell commercial Group 31. I don't know how old they are.
For replacement, I plan to use 3 of the Duracell Ultra Platinum Group 31 SLI31AGM. These are AGM, maintenance free and with both deep cycle and starting uses. The batteries are 100 AH and each with a CCA of 925 Amps with a 48 month warranty.
I would have preferred to go with an appropriate Duralast battery from Autozone. Since Autozone has locations all over the US, it would have been easier to find a replacement in the future. But, as it turns out, the Group 31 Duralast battery was difficult to find at many local Autozone stores that I called.
There is a Digital VSR in the engine compartment. There is another unit there, which may be a diode isolator. I'll find out later once I open the hatch door over the engine from the bedroom.
[UPDATE 4/29] The second unit is indeed a diode isolator. A Cole Hersee 48160. I still don't know what kind of alternator I have in the bus. I'll get under the bus over the weekend and find out. What would be the advantage of replacing the diode isolator with a FET type, like a Victron ArgoFet 200/3? Would changing the isolator depend on what alternator I have in the bus? As you can read, I'm a rookie, but willing to learn.
What I plan to do for the chassis batteries:
- Add a 50 Amp DC to DC charger between the 200 Amp alternator and the battery. This is so I can limit the current from the alternator and provide 3 or 4-phase charging for the batteries. Supposedly, AGMs like getting charged at less than 20% of the amp-hours for the batteries. The 3 AGMs total 300 AH, so 50 amp charging from the battery to battery charger should be good for them. The limiting of the charge current for the chassis batteries will also allow me to eventually have another 50 Amp DC to DC charger powered by the alternator and going to the house batteries. So a total of 100 Amps draw from the 200 Amp alternator.
- Remove the DVSR? This is because with the DC to DC charger a VSR would steal charge from the chassis batteries while charging. Connecting it to the alternator would not be appropriate either, since I also do want to do 4-phase charging of the house batteries from the alternator with a DC to DC charger. [Update 5/3]: Not sure about B2B chargers for the start batteries, so this is still up in the air.
- Add a small solar panel and PPT charger to trickle charge the chassis batteries when parked.
- Add a DC to DC charger from a future inverter/charger to charge the chassis batteries from the house batteries or shore power, as a last resort for charging the chassis batteries. I would either connect the Boost switch or add another switch to only make that connection when absolutely necessary.
Questions:
- Any recommendations or comments on the above? What else should I worry about as I make the above changes?
- Is the 10 KW generator powered from the chassis battery?
You should be able to easily answer this question by looking at your "Automotive Wiring Diagram". If you do not have the wiring diagram for your coach then you are shooting in the dark.
On our '93 (which may bear no resemblance to your much newer coach) the generator starts off the coach (house) battery bank. Cable to starter comes off the battery disconnect switch POS (+) post.
My generator comes off the house batteries. I can tell as the lights inside dim when the generator starts.
I just installed a Victron Orion TR 30 amp battery to battery charger to charge the house batteries at the LiFePO4 profile. I don't think the Orion allows a 3 stage charge to the chassis (engine) batteries since the 12v+ supply comes from the alternator connection. I would think in order for it to provide a 3 stage charging for the chassis batteries it would need a separate power connection and a separate 12+ for the chassis batteries. I think the alternator controls the charging to the chassis batteries. I know, lots of thinking going on so please correct me if I'm wrong. Also a different brand battery to battery charger may have different outputs.
Folivier,
From what I know, what I would do is connect the alternator to the input of the DC-To-DC battery charger. The output from the battery charger would then connect to the new AGM chassis battery. A 4-stage battery charger is probably what I'll use.
Connecting the alternator directly to the AGM batteries means those batteries never charge fully. But, someone please correct me.
I don't understand that statement. (??)
If you run an alternator
long enough it will fully charge any battery, regardless of type (assuming the alternator/voltage regulator are operating properly).
I modified the charging system on our coach. The alternator is connected directly to the (single AGM8D) start battery, and the "sense" wire is connected directly to the start battery.
My AGM start battery charges fully every time we drive the coach. (See Reply #2 in link below)
Delco Remy 28SI Alternator Installation (https://www.foreforums.com/index.php?topic=40778.msg405081#msg405081)
Hello Peter & Patty:
Congratulations on your coach. You'll not be disappointed.
There are dozens of ways to modify your chassis and house charging system depending on you needs, and dozens of well qualified owners here who have experience. I suspect that it would be very helpful to post how you intend to use your coach, how you store your coach, and precisely what components (make and model) you are considering. A goal of "better charging" is very subjective and differs wildly depending on one's aim. The engineers at Foretravel designed a charging system that works well, but falls short for some users given their circumstances. For me going from campground to campground and storing my coach with AC power available, the factory design proved to be just fine. My Optima Yellow Top chassis batteries last 6+ years, and my coach Lifeline AGMs lasted 8+ years. I did upgrade my electrical system, but it was due to aging out and an inverter failure. I also have a 2004 coach. I went with the Victron Argo Fet 200/3 isolator simply because it contains no diodes to age out. It also has the "advantage" of having almost no voltage loss. Not that big a deal with the alternator sensing wire. Your DC/DC charging idea is a creative one and has some complexity. You'll just want to be sure that the complexity and expense solves your problems given your intended usage. Before I tackled my batteries, isolator, charger/inverter, alternator adjustments and solar controller upgrade I searched and read all those topics here. I came to understand why some owners went one way while others went in a different direction. I ended up rejecting a number of well thought out systems because I'd never benefit from them given our usage. I did, however, incorporate a number of other ideas that fit really well with the way we use our coach. I'm guessing that the more precise you are about the why and how you are proceeding the more likely you'll be to get thoughtful input from all these smart folks. Enjoy the ride!
Mark
Hi Chuck,
I was referring to the higher absorption voltages that AGM batteries need to fully charge. Higher than alternators can supply. Also, supposedly, the AGM batteries will last longer if charged with multiphase cycles. But, obviously, if the manufacturers are giving out 4 and 5 year battery warranties while charging with just an alternator, then may be we shouldn't worry about using a multiphase charger at all. May be just replace the batteries as soon as the warranty expires.
Also, with the Boost switch in the FT, it's no big deal if the battery or alternator die while mobile. You can always use the generator + inverter/charger + house batteries + boost switch to keep going. Hmmmm, I think I'll carry a spare boost relay in the RV, just in case. But first, I have to find out where it is in the bus. Is the boost relay the DVSR? I told you I'm a rookie!
The bottom line may only be that all the battery charger will do is just keep your AGM starting batteries and possibly the alternator healthy for more years. And then, if you carry around an AGM battery load tester you may be able to know when to replace them? I wonder if RVers carry battery testers with them? But, the battery charger would be an additional point of failure for the bus.
The input of the B2B should be attached To a terminal that combines the start positive and the alternator output. Then the alternator voltage needs to be turned down to 14.2V Roger posted a picture of how to install the B2B
Peter,
What voltage do you think is required to fully charge the AGM battery? I can't know where you are getting your info on AGM charging voltage (unless you quote a source). There is much conflicting battery charging data on the web. You have to be careful taking everything you read as gospel.
One of our most respected Forum members posted a very good analysis of the charging requirements for AGM batteries. Don tends to do careful research before he posts, and usually has sound data to back up his statements (in this case he references a Deka document). I will link to his post below.
You will notice that Don (and Deka) both believe that AGM batteries will not require more than 14.4 volts DC from whatever charging source to properly charge the battery. 14.4 volts is well within the voltage output capability of most any alternator. To
insure that the battery is actually seeing 14.4 volts
at the POS battery post it is important to use a alternator with remote sense capability, and to connect the sense wire directly to the battery POS post.
AGM Battery Homework (https://www.foreforums.com/index.php?topic=25597.0)
Hi Chuck,
Thanks for the link. There sure is great information in this forum. It's the reason that I felt comfortable deciding to put my money into an old FT.
From what I could find, Duracell says not to charge their AGM batteries above 14.8V. I'll continue to research this and see if there are good reasons either way. That is, alternator only charging or putting a dedicated battery charger between the alternator and the AGM.
What about the Float maintenance voltage that you can get with a dedicated charger? The alternator would not do that for you. I don't know what that would mean to the life of the battery. But I guess that would depend on what kind of warranty you get.
Hi Hach,
I love my FT. It's a wonderfully made machine. But, I do have lots to learn.
My wife and I just retired. I'm 65 and my wife is 70. We hope to get on the road with our Chariot in a few months. Before we do, the bus could use new tires and new batteries.
Our plan is to see this beautiful country. Lots of boondocking, including multiple weeks out in the desert and some nightly stays at Harvest Hosts. Half the time may be with hookups at campgrounds. We will be part timers. May be 6 months out of the year. For the foreseeable future, when not camping the bus will be stored without hookups. I do plan to add solar, so the plans do include a trickle charge into the chassis batteries while stored. To that end, a possibility would be a Renogy DCCS50. It combines a DC to DC battery charger and an MPPT controller. It's not a great MPPT, since it only allows for a maximum of 25V from the solar panels, but as an AGM charger from the chassis battery side of the isolator, it may work out great.
DCC50S DC-DC MPPT On-Board Battery Charger | Renogy Solar (https://www.renogy.com/dcc50s-12v-50a-dc-dc-on-board-battery-charger-with-mppt/)
For the rest of the electrical system, I'm planning to use Victron components. It is easier to update all the firmware in all the modules when using the same vendor. I plan on plenty of solar and possibly two of the Multiplus II or Quattro hybrid inverter/chargers and lithium house batteries. If I were younger I would take my time in upgrading the electrical system. But, even though my wife and I are healthy now, I want to upgrade my FT so we can enjoy it right away, the way we plan to use. We never know when our health will keep us from enjoying the RV life. So you have got to "Live a Little", while you still can.
I don't know if that is correct or not. I think you would have to know the exact operating parameters of the particular voltage regulator fitted to the particular alternator, and how precisely that voltage is controlled.
My
very general understanding of alternator internal regulators is that they work in the voltage range between about 13.5 volts and 14.5 volts. When electric
system voltage is at the high end of this range the regulator reduces alternator output. When system voltage gets down to the low end of the range the regulator increases alternator output.
Remember, the alternator does not just charge the battery. It must also support the demands of the entire 12 volt system in the vehicle. When driving, if you turn on your headlights, the dash volt meter drops due to higher power demand. The alternator must cover this higher demand PLUS keep the battery charged. Alternator output is constantly changing as you drive.
I'm not saying a simple alternator is a
better charging source than a "smart" 3-stage battery charger. But I think most alternators
can keep AGM batteries fully charged. A "smart" charger might very well contribute to a longer battery service life.
One thing to also consider is the alternator will produce more amps than most B2B's. If you have both alternator and B2B connected to the chassis batteries I'm not sure how they will work together.
Hello Peter & Patty.
Thanks for the details. We have an awful lot in common besides the year of our coaches. I, too, am a Jersey boy now transplanted to California and 65. For the past decade we were fortunate enough to travel all of North America in our FT. Your 50/50 off and on the grid does present some challenges. Desert temperatures also affect the charging profile of your batteries so you'll probably want to include temperature compensation especially while the alternator is running. The most important variable as mentioned above is to get your charging system to match the chemistry of your batteries. East Penn has excellent data published regarding temp compensated charging profiles of AGMs and GEL batteries, and Don's posts are also helpful. http://www.eastpenn-deka.com/assets/base/0139.pdf
There are plenty of owners here that have tremendous experience with Lithium batteries as well. Given your demands that may also be a serious consideration. Again just tailor the charging system with the battery chemistry.
The alternator comments above are very constructive. From what I've read a lot of off-grid folks have done very well by spending more time on battery chemistry (Lithium, AGM, GEL) and solar, and less time redesigning their alternator charging system. It might be that an external regulator with temperature compensation is all that may be required of your alternator. Like I said at the beginning there are dozens of ways to skin the cat. There are a lot of solutions published on this forum that will help you decide.
"To that end, a possibility would be a Renogy DCCS50. It combines a DC to DC battery charger and an MPPT controller. It's not a great MPPT, since it only allows for a maximum of 25V from the solar panels, but as an AGM charger from the chassis battery side of the isolator, it may work out great."
Did the same thing 2 yrs ago but after trial and error I figured out that your batteries will hold a charge quite well on there own if you install a disconnect switch on both sets of batteries and turn them to off when you store your RV. Much cheaper than a trickle charge solar system. I had 200watts and it didn't keep up during the dreary winter days with no sun.
Great information above. Thanks all.
I just returned from checking a few things in the bus. It turns out my 2004 has the stock alternator, LN model A0014884JB. I didn't get a chance to check all the voltages at the battery isolator yet, but it should have both Excite and Sense Cuvac terminals.
I wonder how much longer that alternator would go? In doggy years, it is pretty old. If I ever need or want it replaced with a brushless version, would a good replacement be Delco Remy 40SI?
Prestolite - Leece Neville (https://www.prestolite.com/pgs_products/specs.php?item_detail_id=855&item=A0014884JB&product=ALTERNATOR)
Delco 40si 240 Amp Alternator, Sterling ProSplitR Installation (https://www.foreforums.com/index.php?topic=28384.0)
Oh no. If I use a B2B, the alternator would not go to the chassis battery directly. I would think the alternator B+ would continue to go to the Alternator middle terminal on the isolator. The chassis side of the isolator would go to the B2B. The output of the B2B would then go to the POS of the chassis battery. The House side of the isolator would then go to whatever B2B I would need for future Lithium batteries.
My cousin has a Balmar Regulator hooked up to his leece neville alternator so he can set it up the charging rate any way he wants.
I might do it to mine some day.
With that arrangement, there would be no point in retaining the diode isolator (with its attendant voltage loss across the diodes). You could toss it and run the alternator B+ (using 2 separate cables) directly to the inputs of both B2Bs.
Could the gen auto start possibly be used to kick in when the trickle charge from solar for the chassis battery is not getting the job done? I suppose you would have to store the bus with the Boost switch on to get the charging from the inverter/charger over to the chassis batteries. But, I don't know enough about how to best use my generator auto start yet.
Yes. May be. Even if I change from the diode isolator to the FET type, may be the FET isolator would not really be needed either. There may be some issues with fusing to the B2B, the boost relay. I haven't thought this through completely yet. I need to start digging into the wiring diagrams.
I wonder if others have thought about this and can comment. I can see why back in 2004 the isolator was a must. But, not sure now.
[Update 4/30]: I started looking at wiring drawing B2126. I think the first thing that I would do is replace the Diode isolator with an FET type, Sterling, Victron or other. That is a more reliable upgrade from the diode isolator currently in the unit.
Then, if I decide to change my wiring for charging both the chassis and the house batteries with B2B chargers, I would still include the FET isolator. This is so you could remove the B2B chargers and easily restore the wiring as it was when the coach was built, as per B2126, if you ever wanted to.
For the new wiring to B2B chargers, I would probably attach the alternator cable to a post by where the isolator is currently mounted. This way you don't need to change the length of the 12V cable from the alternator to where the isolator is. From that post, I would probably run a beefier cable to the Alt. post of the isolator and to a post connection under the bed, on the inside of the bed framing, by where the breaker boxes are. Larger cables in case you upgrade the alternator later. Then, you could wire from that, through appropriate fuses to the inputs to two or more B2B chargers, as needed, and still mounted under the bed. You would then set the B2B chargers to whatever battery chemistry you're using, AGM or Lithium. Then, you would run through some fuses and connect each B2B output to the appropriate side of the Boost relay. One of those connections already going to the Chassis battery circuits and the other already going to the Home battery bank, as per B2126. These changes and additions to the wiring could be an additional page added to the set of wiring diagrams for the coach for the next owner, if need be.
Might get some ideas from this post with Rogers suggestions on hooking up a B2B
Another lithium upgrade. (https://www.foreforums.com/index.php?topic=41960.msg419477#msg419477)
It could but you shouldn't need it. I put in a disconnect and both batteries stayed at 12.8 or 12.7 for months. It's recommended by many on this forum to monitor your coach when in storage and to start and run your aqua hot once a month when not in use. So you could check on your batteries then. I used these disconnects for start
Amazon.com : Blue Sea Systems e-Series On/Off Battery Switch : Boating... (https://smile.amazon.com/gp/product/B000MMC914/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1)
And house batteries
Amazon.com : Blue Sea Systems HD-Series Heavy Duty On-Off Battery Switch,... (https://smile.amazon.com/gp/product/B000MMDLB6/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1)
Something to keep in mind (based on a lot of testing I did when modding my coach) is your coach chassis system typically will require more than 50 amps running down the road, at times much more. My coach just idling in the driveway consumed about 30 amps, for engine and transmission CPUs, dash gauges. Now consider driving with headlights on, heater/defrost blower on, wipers on. This load must be supplied, and you need more if the batteries happen to also need recharging. This could easily approach 100 amps or more.
I would recommend getting a DC current clamp meter and do some testing to understand your coach chassis DC current usage with typical and maximum loads as you are planning your upgrades.
Excellent post. Absolutely, I forgot I'm dealing with the needs of a bus and not a car. May be the batteries will just need to continue getting charged directly by the alternator for now.
I wonder if any other motorhome manufacturers are using B2B chargers for their starter batteries.
Now that I know I have a 17 year-old alternator in the bus, may be I should just look for a good quality replacement like a Delco. Upgrade the alternator, the chassis battery and change the Diode isolator to a FET unit and forget about doing multi-phase charging of the chassis battery.
Here is a previous post with some ideas.
Homemade B2B charger project (https://www.foreforums.com/index.php?topic=41818.0)
I would recommend upgrading to a Delco, either 28SI, or the brushless 40SI or 55SI (now available with J-180 mount). Several members (including myself) have installed Delco alternators with excellent results.
As has been (extensively) discussed previously, the Delco needs voltage on the B+ terminal to start up so (contrary to some claims on this forum) it will not function properly when connected to the OEM diode isolator and is not a drop-in LN replacement.
Any isolator with an excite terminal will work with a Delco - diode isolator with excite terminal, Sterling Pro-Split-R or Victron FET - or - connect directly to chassis battery and use a VSR + B2B as the isolator, or a manual switch as some have done. I believe the Sterling B2Bs have an ignition turn-on option so wouldn't need a separate VSR.
The start batteries using my Delco 40sI 240 amp alternator charge up quickly after a start and then charging voltage dips to 14v or a bit less. Start battery voltage as reported by the ECU with headlights on at normal road speed is 14v.
I had more than 1500 amphrs of AGM batteries when I went to a 240 amp alternator. When you switch to lithiums you want to limit charge to 20% of capacity from all sources. If you have 600 amp hrs of LiFePO4 batteries then the max charge is 150 amps. With 1200 watts of solar 40 amps is pretty good driving down the road, with a 30 amp B2B you are up to 70 amps. Start the gen to run AC and that could add another 100 or more.
I rarely actually enable the 60 amp B2B Sterling charger when we drive. We left TX last week for MN and drove 1400 miles or so and never had the B2B charger on. Even with a residential refrigerator on we arrived home at 100% SOC from solar charging alone while driving.
And in five months away this winter the charger side of the inverter was on for three days. All charging to the house and start batteries came from our solar. There were very few days when we didn't end the afternoon at 100% SOC, usually by noon.
So you don't need a monster alternator if you have LiFePO4 batteries and a pretty normal sized battery set and inverter. If you are going to go to a huge battery set, very large inverter(s) and are hoping to run AC while driving from batteries and inverters then a much bigger B2B is likely needed and alternator too.
BattleBorn makes an on/off battery charge controller. It lets your alternator blast the LiFePO4 batteries with all it can for a short while and then shuts off for a longer while and then repeats the cycle. It is sort of a brute force way of treating your expensive batteries when there are smart multi-step charging processes available.
The Sterling ProSplitR is a fairly smart zero voltage loss isolator. The start battery post and alt post are internally connected so that the Delco is ready to go with no excite wire. It starts charging only the start battery until it reaches a particular level and the switches to the house battery and charges them. While doing that it monitors the start batteries and will switch back to them as needed and then back to the start batteries.
Don't overcomplicate things. Make sure you can monitor each part of the system. One of the benefits of an integrated approach from Victron is that monitoring everything gets easier.
Yep. I think I'll upgrade the alternator next. Since I plan to install as many lithium batteries as the budget and room in the RV will accept, I will see if the Delco 55SI can be installed. It will probably be the last alternator for that MH while I'm alive, so go big. What I'll probably do is upgrade the B+ and ground cabling from the current alternator to the isolator myself, as appropriate for the new 430 amps. This will give me a chance to see if I really want to change the alternator myself or hire a mechanic to do it. Getting too old for the heavy stuff, especially in the limited space by engine. I will also research and upgrade to an appropriate FET compatible with the 55SI.
I need to search the forum to see if anyone else has done the Delco 55SI install and new J180.
Roger,
I have been reading some of your posts on batteries and solar. For your chassis batteries, are you still charging them directly from the alternator or do you have a B2B charging them? Are your starter batteries AGMs?
Here is one source, search for Delco 61003345
Delco Remy 55SI 430A Alternator - 61003345 (https://www.jittruckparts.com/alternator-55si-12v-430a-61003345)
The thing to keep in mind is just because you have an alternator capable of 430 amps, it will only supply what is needed at any given moment. The alternator will run cooler, last longer, and handle whatever you decide to do. You will definitely need to keep us up to date on your project - and with lots of pictures!
Here is the 55SI brochure
Peter, my AGM start batteries are charged from the alternator directly and the house batteries through a Sterling B2B charger controlled by an ignition source. It can also be turned off.
Both battery sets are charged by solar.
I also have a Sterling 40 amp charger the charges both the start and the house batteries if it is on, generally not on.
My Victron multiplus charger is rarely on.
All chargers use a LiFePO4 charge profile.
Here are some preliminary ideas that I'm playing with for the changes to the chassis power in the bus.
1 - First, I'll need to confirm that there is room to put the Delco 55si in the same place as the current alternator. If so, the 55si goes in. In my opinion, it's about time large diesel motorhomes put a large alternator like that into the bus. With most toads likely going hybrid in a few years, I could see the generator and alternator in the bus getting used to charge the toad while driving down the highway. I plan to upgrade my aging 2012 Jeep Wrangler to a hybrid version in the next few years.
2 - Along with the 55si, I'll update all the wiring from the alternator and go with an appropriate FET isolator. I'll add some power studs located close to the isolator to make it easier to tap into the voltage from the alternator, Chassis and House batteries for future expansion.
3 - Since 3 of the Optima Yellow-Top batteries have been used in the past as starting batteries in older U320, then it means that you may need almost 2000 CCA for the 500 HP U320? I wonder if anyone knows the recommended CCA to start the big engine.
4 - I have 3 aging but still working Deka 8G8D House batteries. Those babies are deep cycle, but they do pack 1150 CCA at 225 Ah each. There may be room next to the current 3 Group 31 chassis batteries in the bus to frame for 2 of the 8D batteries. Now, just thinking aloud for now. I know, I'm not keeping it simple, but just hear me out ... My sandbox idea would be for two banks of batteries for starting the bus. Is this needed? No! Then Why? Read on. One starting bank for starting with the current 3 Group 31. I could just let those aging batteries continue to be charged directly by the alternator. Another bank that could be used for starting as well, made up by 2 of the Deka 8G8D borrowed from the House batteries. Those would be charged by the alternator, but through a B2B charger at around 100 to 125 amps. When starting, I could either combine all the batteries or may be just select the bank that I would want to use at any given time.
Now I hear you saying, why? Why do this? Why not let things be. Good question!
One plausible answer, "says the mad scientist as he takes another sip of wine", is that the current 8D batteries and Group 31 batteries are still operational. I haven't put a battery tester to them, but they still hold a charge. The 8D Deka are not my preference as House batteries for all my planned boondocking, but I would like to continue to use them in the bus for now, instead of just discarding them. I could use them as chassis batteries until their demise, especially since I still have 3 Group 31 in the mix. In addition, once I build a frame to hold the 2 8D batteries and a place for the B2B charger by the engine, once those 8D do die, I could replace them with 2 8D Lithium and then just switch that bank to be used as House batteries. The B2B charger would then just be switched to a Lithium profile. And remember that future hybrid toad. That engine area is not too far from it. Those future lithiums, could be a nice energy storage buffer for the alternator, the generator and solar to the electric system of the toad. A second battery bank for the electric toad. I would just need an inverter from that bank and some wiring running to the toad to charge it.
[Update 5/3] As per Peter's reply #35 below, that future lithium house bank, possibly 2 of the 8D "buffer" battery setup, located by the engine chassis batteries, at possibly 540 Ah (2 Battleborn BB8D), and an appropriate inverter could run an AC nicely while driving.
Having a larger alternator does open up all kinds of possibilities. I think that is the first upgrade, right after new tires.
Remember, just thinking aloud here ... "Says he, with a funny grin, as he continues to sip more and more of a good wine". "Cabernet Sauvignon Markham Napa Valley Vineyards, 2017".
One additional idea for you - a goal of more than one member of this forum (including me) - is to power a roof A/C with inverter and alternator while driving. I did it with a 300 amp 40SI, your 430 amp 55SI won't even break a sweat...
I'll throw this out there, when wiring up your new Delco, there are only 2 connections - the B+ post and the "S" sense terminal (and I would recommend a dedicated high amp ground wire from alternator to battery bank). Do not connect an excite wire, the terminal labeled "I" is for a dash indicator lamp, not ignition excite - this will ruin your shiny new 55SI. Excite is provided by having 12v on the B+ as discussed earlier, either with isolator that has excite terminal, or direct battery connection.
Your aging 8D batteries are most likely nowhere near their original capacity. You have to work hard at making that happen. I have 21 yr old 8D batteries that charge and hold some capacity but not what they originally did. Take your aging 8Ds out and use them in a solar storage bank. Consider L16 sized 6V Full River AGM batteries for house batteries.
3 group 31 AGM batteries will start your engine. No need to lug round extra weight. Use the Boost Switch if needed. Upgrade your start battery wiring and increase cable size to the starter motor. A gear reduction starter takes less amps to start the engine.
A B2B charger with AGM batteries and a giant alternator doesn't make much sense to me. You might be able to push 60 amps into them (maybe more with a home made set up) but not what your big alternator is going to put out, certainly not enough to run an AC or 2.
Step back, look at loads and sources, a balanced system is going to work better. AGMs and LiFePO4 batteries need different treatment. And cabling for a 430 amp alternator from the back of your coach to where your batteries and inverter are located is going to be way more thn the 1 3/0 cable that is there now. I used 2 4/0 + and + cables for 240 amps. You need to pay attention to fuse protection at the source end as well and at the other end.
Yes, system needs to be designed for your wants/needs. The A/C option will need about 150 amps, too much for a B2B charger. One solution would be a dedicated inverter just for the A/C circuit, directly connected to the alternator/chassis battery thru a VSR, then also use a B2B for the house side to get the battery charge profile options.
All things are possible with lots of $$$ and maybe more critically in a coach - cabling, space and weight distribution. I see a lot of newer coaches with big alternators more power moving batteries and inverters further back towards the tag axle. When I switched from AGM to LiFeFO4 technology I saved about 1000 lbs and in my coach that was all at the front end of the basement mostly on the steer axle.
Here is the Blue Sea wire chart. 4/0 both ways (B+ and Gnd) should handle the 55SI output.
4/0 from the alternator to the isolator is OK but from there to the front of the coach where the 12v distribution panel is likely 60 ft round trip. That many amps in a single 4/0 cable would get you more than 8% voltage loss. To get under 3% for that length of cable at 12.6 v and max alternator output you would need 4 4/0 cables.
And you need a similar negative side as well
Bos'ns' Corner - Wire Size Calculator (https://baymarinesupply.com//bosns_corner_wire_sizes)
Now that right is some serious cabling
On my '91 the battery box was fairly close to the engine bay, sounds like some equipment re-location may be beneficial for your situation.
On the subject of 12v cables, several members (including myself) have invested in a good crimper and learned how to make our own 12v cables. Searching cable terminal and crimp tool will give you multiple posts on the subject.
In the interest of not buying any component that I won't need going forward. I think you're right in that if I install the 55si, there would be plenty of juice for both the chassis battery and any house batteries powered by an appropriately sized B2B charger. So no need for an isolator or the VSR at all. It would make sense to keep the boost relay for that one day in the future when the chassis batteries are dead and the only way to get going is with help from the House batteries.
So, bottom line, 55si getting its Sense voltage from POS of chassis battery bank. An ignition enabled B2B charger with an additional switch to turn it off when not needed, similar to what Roger did. Any other unexpected consequences of removing both the isolator and VSR from a U320?
Yes, good to go. May want to keep VSR for any future high current options (inverter powered A/C) that you want to have the alternator supply directly.
Hi Roger,
I definitely do not plan to get send the 12V DC alternator current directly to the House batteries up front. The House batteries up front can be charged with solar, and inverter/charger from shore power or generator. Charging those from the alternator as well would be overkill.
I suppose at the cost of efficiency, if you had to, you could invert the alternator to AC and ship that to the inverter/charger up front. Smaller wires for AC. Likewise, you could run AC wiring from the shore inputs and generator to the inverter/charger in the back.
[Update 5/6]: Alternatively, if you don't already have an inverter connected to the alternator in the back of the coach, you could add a DC-to-DC converter back there to get 48V or 24V from the 12V from the alternator and ship that to a DC-to-DC converter connected to the House batteries at the front of the coach. For example, a Victron Orion TR 48/48-8 can provide a maximum of 430W to a 48V battery bank. Relatively small wiring can now carry that power from the alternator from the back of the bus to the House batteries, when those are mounted at the front of the coach. In the example above, the 430W is just 35 Amps drawn from your alternator and less than 10 Amps traveling down to the House batteries at 48V.
But, what I think I will do is explore a second lithium house battery bank close to the back of the coach, closer to the alternator. There is unused space now next to the chassis batteries, But, I would need to fabricate some frame for that bank. Batteries under the bed or in the closet are other possibilities for lithium. I wouldn't put the inverter inside the coach, because of noise, but the Battleborn BBGC3 profile of batteries would be acceptable inside the coach. The inverter/charger would probably fit nicely in the space near the chassis batteries. BTW, under the kitchen sink, towards the back there is a space where a subwoofer is installed. I could always take that subwoofer out and put another house bank there for the refrigerator. That bank could be charged from the inverter/charger up front and from solar. But, I have enough projects for now. So, the subwoofer lives another day.
As Peter discussed in entry #35 above, I'm envisioning the larger alternator running cooler and living longer while at the same time providing for the needs of a house battery bank at the back of the coach. It would be an improvement to be able to run air conditioning quietly while driving. That's a nice idea. Also, just like you did, that same bank may also be big enough to run the refrigerator on AC while driving.
Lots to think about. Now that I'm retired, thinking is much more fun than watching the grass grow.
Peter, I would like to suggest you take all of this under advisement and do nothing for at least a year. Get out and use your coach fpr a while, figure out how things work, how you use it, what level of power requirement you have and start to understand how you will use the coach. I know it is interesting to think about all of the possibilities and you are eager to get started but a years worth of experience will help focus your efforts towards what really is important to you, not just what you think they are now but what you will come to know.
You will find all that unused space you see now will be harder to give up in a year. Really.
In a year you will be much better able to conceive of and design a system that meets your needs. Technology will evolve, new choices will be available and prices may go down.
We are 10+ years on our coach now, still learning, still changing, getting older and maybe wiser.
Roger
Very good advice from Roger. We bought our coach mainly for an Alaska trip. I installed 400 watts solar + 300 amphours of Battleborn batteries. That worked great for that trip due to the long hours of daylight in Alaska. But now our way of travel has changed, we bought a lot with full hookups in the Colorado mountains for the summer and take other shorter trips during the winter. Now we seldom spend more than 1 or 2 nights dry camping so the solar and BBs work great for our type of travel.
In fact we could do without the solar + BBs. I thought about adding more solar and BBs but glad I didn't. So even if you think you have your plans set they will probably change.
Absolutely. You need to know what you want before you do anything for it. In my case, I'm looking for flexibility. I had a 34' MH about 20 years ago. I was always constrained on what kind of dry-camping I could do because of limited House batteries. Then I bought the 17' TT and I had to run the Honda generator mounted in front of it all the time whenever boondocking. From now on, I want any limits to dry-camping to be because of limits with grey, black and fresh water tanks and not because of off-grid power limits. With current lithium technology, inverter/chargers, generators, solar, large alternators and a 40' tag axle MH, there is no excuse for not having enough flexibility with the electrical for the bus. There are always budget constraints, but not technical ones. To that end, I'm going through the wiring diagrams for the U320 and also checking what's actually wired in the MH before I make any changes. I have no idea what the previous owners may have changed in the bus. Also, have any actual changes been updated in the wiring diagrams for the MH?
One of the things I plan to do is check for any current corrosion in the wiring. I already noticed corrosion in the connections for the chassis batteries. Also, no terminal caps to protect those connections. I need to add some bus bars in place of some of the splicing used for 12V and Ground connections on the bus. I still need to check the inverter for corrosion and the quality of those cable connections.
I may not know everything I should know, but I'm willing to learn. I bet you there are a lot of motorhomes out there with really bad and even unsafe electrical setups.
Here is a DelStar 55SI equivalent - maybe do a cost comparison. On brochure they have an interesting air intake option to supply cold outside air instead of hot engine room air.
Heavy Duty Brushless Alternators (https://delstar-hd.com/results.asp?q=61003345)
Peter,
As built FT were up to standards of the day. Today, fewer connections per post and more fuses/circuit breakers are part of the current standards. Switches are common in connections especially where multiple power sources are present. Big circuit breakers that you can open are often used in place of a switch and a fuse but there is some concerns about frequent use of a circuit breaker as a switch.
Corrosion on lug ends is common, use a wire brush or a abrasive brush on your drill to clean them up and then brush lugs, posts, nuts, bolts and washers with a thin coat of an electrically conductive grease. NO-OX-ID "A Special" Conductive Terminal Grease (https://baymarinesupply.com/no-ox-id-a-special.html) one container will last forever.
1200 watts of solar will charge 600 amp hrs of LiFePO4 batteries with enough to meet your typical needs even with a residential refrigerator. What your typical use is can only be answered by you measured at different times of the year. We use 2800-3200 watts per day. Sometimes 3600 watts but generally no more. If you have an electric cook top it will be more. More solar is nice if you can fit it up on the roof, it charges batteries faster and adds more time during the year when solar is sufficient to recharge batteries. We have 1200 and I have room to go to about 1900. Space on the roof is at a premium so higher wattage 60 cell mono panels get you more watts for the space used, not necessarily cheaper per watt. Wire in parallel to minimize shading issues. Series might save a small amount on wire but at a big potential production penalty. Your coach will never be like a great solar facility. You will rarely have a perfect location. So just make it as good as it can be.
More battery capacity is just that. With LiFePO4 batteries cycling anywhere in their SOC range is OK. With AGM or GEL you eally need to go back to 100% SOC every cycle. With more LiFePO4 capacity the daily range relative to capacity is smaller extending the life of the batteries further. And with more capacity you have more buffer against multiple days of bad solar weather. We did 8 days in the Tetons last summer with 600 amphrs of LiFePO4 batteries and 1200 watts of solar and 1-1/2 days of rain and everyday late afternoon shade. We started at 100% SOC and when we left (9AM) we were at 85% SOC. A couple hours later we were at 100% SOC. No generator time at all. No land line.
We have a B2B charger for the charge-while-driving part of the equations. It is almost never enabled. Solar while driving is sufficient. At the end of a driving day we are almost always at 100% SOC. Not always, a day driving in heavy rain and sleet was tough but I can enable the B2B with a single switch.
We also find if we are in an RV park for a while on metered electric that solar alone is sufficient to charge batteries everyday, 120v chargers are off, refrigerator is running on our small inverter and 120v is powering the AH when it is on (2-4 hrs a day), AC when it is on and some other small loads. In this case our metered electric charges are generally 1/3 -1/2 what they might have been without solar. This winter our monthly electric charges we about $40 in metered sites,
LiFePO4 Battery technology, capacity, quality and pricing is changing rapidly. BattleBorn is still the gold standard but there are other choices worth considering at lower cost. Some of the choices boil down to the physical space where you want to put the batteries, what fits. And where your batteries are now does not mean new batteries have to go in the same space. In your case the batteries are in a center cave in the basement. You need to consider access for service, switches, fuses as well as where solar charge controllers are located and wiring paths and distances. My coach is different from yours but the issues are the same and the solutions while different can be just as efficient.
So the first thing you need to know is how much energy (watts) do you use on a typical day during different seasons. And then how are you going to use your coach. That will change over time. And then start thinking of solutions that provide the resources to meet your needs with perhaps some excess capacity built in up front (cheaper then than rework later).
More than anything use your coach to discover how it works, how you work in it, what you like and what you think you can do to improve your experience in the coach. In the end that is the only reason to change anything. Life is good, make it better.
Roger
Hi Peter,
I noticed the Delstar puts out 260A at 2000 rpm. I wonder what the idle amps are for the 55si? I could not find it online. Also, do you know what the alternator ratios are for the LN, 55si and Delstar? I'm just wondering if there would be a need to change the pulley at the alternator.
On the 55SI brochure a cpl of posts back, it looks like the 55SI is 250 amps at 2000 RPM, the Delstar outperforms just a little both at idle and full output.
What I would recommend is to put a laser tach on the LN you have now - at idle, hopefully it is somewhere near 2000 RPM - then you will know if you might need to tweak the pulley size - smaller for higher RPMs.
Here is the tach I have and used to check my 40SI RPM. If I remember correctly, been a few years, I think with the DD 6V92 the alternator was running 1800 RPM at engine idle of 600 RPM, so 3 to 1 ratio.
Neiko 20713A Digital Tachometer, Non Contact Laser Photo | 2.5 - 99, 999 RPM... (https://www.amazon.com/dp/B000I5LDVC/ref=cm_sw_r_u_apa_glt_fabc_0FWN70Z5MEDFE4X5VG7N)
20A Level 1 EVSE ACS-25 | ClipperCreek (https://store.clippercreek.com/level-1-20-amp-ev-charging-station-acs-25)
Here is a 20 amp Level 1 EV charger, my estimates for alternator power required to run this:
20 amps x 120 volts = 2400 watts
2400 watts x 1.20 (inverter efficiency) = 2880 watts
2880 watts /12 volts = 240 amps
This would give your new alternator something to chew on...
Yep. Good idea. A VSR connected to the chassis batteries. The VSR output connected to an appropriate DC-to-DC charger set up for a Lithium battery bank. An MPPT charger for solar. The lithiums connected to a hybrid inverter/charger. Power from shore/generator could also be connected to the inverter/charger. All of those mounted in the back of the coach by the chassis batteries. Power from the inverter could be used for either an AC or for a future hybrid toad. I like it.
[Update 5/6]: I took measurements next to the chassis batteries. I have room for a box 23" x 21" x 28" (LxWxH). A box there with two shelves could accommodate up to 5 BBGC3 (22.83" x 7.09" x 13.14") and 1 Victron Multiplus II 12/3000/120-50 2x120V (22.76"x10.83"x5.83") if mounted on its side. That would be 1350 Ah and 16.2 Kw-hr. Plenty for charging hybrid toad or running AC for a few hours while driving. If I get a hybrid, I may go for that kind of setup. BTW, the Jeep Wrangler 4xe battery is 17.3 Kw-hr. That is good for 22 miles on electric power. So, the 16.2 Kw-hr lithium would provide a reserve of another 20 miles for the Jeep stored by the bus. Now we just need the price of lithium batteries to come down some more. At about $3000 per BBGC3, that hybrid Jeep can buy a lot of gas instead.
Folivier,
I did some more research on this. It looks like there is no problem connecting an alternator to the output of an MPPT controller or B2B, while all of them are charging the battery. From what I've read, the Solar MPPT controller and the B2B chargers work to supply current to the battery based on the voltage that it sees from the battery. So, while the alternator is running and putting out a voltage like 14.4 the MPPT and B2B charger may just shut down and not put any current out. But, when the engine is off and the alternator is not running, the MPPT and B2B will work to top off the battery depending on its voltage.
Someone please correct the above.
Chuck,
I thought about this some more. I think what I'll do is replace the diode isolator that came with the coach with an FET type. I will also keep the DVSR. The reason for doing this is that even if it is not strictly needed for my customization of the coach, I want the coach to be electrically wired as per the factory. The next owner for this coach will surely appreciate that.
As an example of why this is important. I currently find myself digging through wiring diagrams and the coach to see what modifications have been made to the coach by previous owners without updating the wiring diagrams. I need to go through that exercise before I make any modifications to the wiring.
Wait for smarter members than me for the final answer. If you are just charging AGM's or wet cell no problem. If you are charging Lithium it would be no different than just supplying alternator output to lithium batteries which has been discussed as a bad idea.
Yes, Lithiums will not like charging directly from an alternator, unless the output of the alternator is regulated by a 3 phase charger that can be set to a lithium profile.
For my Chassis batteries, I'll be using AGMs. Most likely 3 Duracell SLI31AGM Group 31. To keep those batteries topped off, I'll eventually connect about 300 watts of solar through an MPPT to them.
House batteries:
So I continue to research and test the 8D AGM House batteries in the coach to see if it makes sense to replace them. At this point, I may want to do so sooner rather than later.
So for a replacement, at first I thought about going straight to Lithium Battleborn BBGC3. But, after doing some more research, I think I will replace the 3 8D with 8 of the Firefly Oasis Micro Foam AGM. That battery is 116 Ah and about half the cost of the Battleborn Lithiums.
Firefly Oasis model # FF12D1-G31
116 Ah
$543
I think I can fit 8 of those in place of the 3 8D inside the middle storage compartment in the U320. I'll probably set them up 4 in series and 2 parallel banks to get 48V. That would be 48V @ 232 Ah. That's the equivalent of 928 Ah @ 12V. That's about 5.5 Kw-Hr if I take them down to 50% DOD. About 2000 to 2500 watts of solar should bring the battery up to full charge everyday. For forecasted cloudy days, 30 minutes of generator time should do the trick. What could be done is to run the generator early in the morning. That way, the generator gets to run during the bulk charge cycle. By the time the voltage is up to 14.4 volts or so, turn the generator off and let the solar finish topping the batteries off with absorption and float.
The Oasis Firefly batteries have been used successfully as House batteries in boats for many years now. They have about 4x the number of discharge cycles as most other AGMs at 50% DOD. At 50% DOD, life is expected to be 5 - 10 years. It's specified for 3600 cycles for 50% DOD. C20 at 5.8A for the 116 Ah. C10 of 11A for 110 Ah. C3 of 30.5A for 91.5 Ah.
Warranty: Free replacement for first 2 years. Pro-rated credit for another 4 years.
The reason for why I'm thinking of using this battery is because of the way I may use the coach for the next few years. The coach may be sitting around in storage, in an off-grid setting, for some periods of time. So the issue is sulfation of AGM House batteries because the battery is not kept at full charge at all times. Now, I do plan to add solar to the RV, eventually, but in the meantime, it is an issue. The Firefly battery has minimal sulfation issues. It can self discharge and then when under charge again, it comes back to the full battery capacity from the factory. This is not something that most other AGMs can do.
Info here:
Firefly Oasis Group 12V 31 Battery - e RV (https://www.ervsolar.com/Firefly-Oasis-12V-Group-31-Battery?gclid=CjwKCAjw-e2EBhAhEiwAJI5jg_uM-pjK3tNn64C7zA8V-h4SCS9TSsMRJbvK7n4j9jLJfHrV1MCkqhoCwk0QAvD_BwE)
This is what I installed and has more usable amps than what you propose. Amazon.com: 12V 200Ah Lithium Iron LiFePO4 Deep Cycle Battery, Built-in 100A... (https://www.amazon.com/Lithium-LiFePO4-Overland-Off-Grid-Application/dp/B088RM4W48)
I just replaced the 3 8D's with these.
Craneman, how are those lithium batteries performing? How far down do you discharge them?
Been off the cord for 2 weeks now. We are in the Sierra's and on cold nights dropped to 60% as the AH ran more than usual. This includes the 22 cu. ft. Frigidaire and watching satellite television until 10:00 pm. and DW's oxygen concentrator running 24/7 Fully charged by 11:30 each day with solar. AH draw reads 244 ahrs in the morning before using microwave and coffee maker. Then it is down 250 ahrs before starting back up. Very happy with the batteries.
I'm assuming that if I want to install a Balmar regulator on the Delco Remy 55si, I would need to remove the internal regulator that comes with the 55si first. I'll contact Balmar and Delco and see what they say.
DelStar has one designed for an external regulator that might work with the Balmar regulator.
DelStar (https://delstar-hd.com/results.asp?q=100-18103)
Thinking outside the box here ...
Has anyone looked into how much loading we can have on the roof of a FT? I mean, we take it for granted that we can install air conditioners and solar panels. But, why not Lithium batteries and inverters. So, I wonder how many lbs per square inch we can put on that fiberglass roof. I could see a few BBGC3 lithiums and even an inverter underneath an AC type of cover on the roof. Then, instead of DC, just ship AC down into the RV. Think of all the room saved in the storage compartments taken up by the batteries now. Put flexible solar panels on top of any of the enclosures for the batteries.
I try and keep the weight low as the coach is more stable.
Consider Enphase microinverters, one on each panel, output can be 120vAC or 240vAC. AC power directly into the coach. You already have chargers, some can charge batteries. So instead of panels to solar charge controllers to batteries to inverters to 120v use panels and microinverters directly to AC.
We have 36 panels all with microinverters on our house. About 10.6KW. Generated > 62KWH net last Monday well more than twice what we used, the rest gets sold back into the grid.
An alternate idea. The picture is from our production monitor, 12 hrs on Monday during the day. The green area is net returned to the grid. On an annual basis we generate about 20% more than we use.
3 of the X2Power AGM Group 31M batteries installed for the engine.
1150 CCA each, 100 AH.
Purchased from: Batteries - Phone Repairs - Light Bulbs - Chargers - Batteries Plus Bulbs (http://www.batteriesplus.com)
After credit for returning old Cores, 10% online discount and $30 mail in rebate for each: $344 ea.
Note: I used a Foxwell BT-715 to test the chassis and house batteries before deciding to replace them. That unit works great.
[US Ship] Original 12V 24V Foxwell BT715 BT-715 Battery Analyzer Multi-Language (https://www.foxwelltool.com/wholesale/foxwell-bt715-battery-analyzer.html)
House Batteries - 48V?
I currently have a Xantrex Prosine 2.5 inverter/charger in the bus. I'll be moving the 3 old 8D GEL Deka 225AH batteries that used to be in the bus home to use as backup power. I will be relocating the Prosine with them as well. So now I need a new inverter/charger.
I would really like to now purchase a Victron Quattro 48/5000/70 hybrid inverter charger. I have already purchased 6 of the Firefly Oasis AGM batteries. I will purchase 2 more to make a 48V @ 232 AH (equivalent to 12V @ 928 AH - 11 KW-hr).
- 48V Victron inverter/chargers are cheaper than the 12V inverter/chargers.
- DC wire size between battery and inverter/charger is smaller for 48V compared to a large battery bank at 12V.
The Quattro is physically much bigger than the Xantrex. It won't fit in the inverter bay where the Xantrex is currently installed. So I will be putting the Quattro at the end of the bay, next to where the batteries are. That is, on the passenger side of the bay, across the wall from where the Xantrex is.
Has anyone here gone to 48V battery banks for the House batteries? I'll start my research here with what others have already done.
Here is a video from a fellow RVer and the Quattro 48V/5000/70 installation.
https://www.youtube.com/watch?v=HfXeNdbiWss
How-To remove 8D 157 lbs batteries from the belly of the beast.
At almost 66 years old and a skinny 150 lbs in weight, I had to come up with a way to smartly remove the heavy batteries from the innards of the bus.
The key here is a hydraulic lift. I bought this toy:
https://www.harborfreight.com/500-lb-capacity-hydraulic-table-cart-61405.html
What I did was disconnect the "U" handle from that lift so it would fit inside the bay of the bus. Then, after removing the Joey bed, I moved the lift into the bay. I then pumped the platform of the lift vertically to be leveled with the battery. Then, after disconnecting the battery cables, I slid a battery unto the platform of the lift. I wheeled the lift out to the edge of the bus. I used a plywood platform to slide the battery to the ground. Then, I moved the hydraulic lift to the ground. I slid the battery on the lowered lift bed. I moved the lift to the back of the Jeep. Then, I just let the hydraulic lift do its thing and lift the battery leveled with the bed of the truck. I then pushed the battery into the truck. I droved home, used the lift to lower the battery to the ground and then used a hand truck to take the battery to its final destination.
Two more batteries to go.
No back pain. Life is good. ^.^d
Seems a long drawn out exercise and money that could be alleviated by paying sone young buck $25 to do 10 mins work to me.
Johnh
You can't get kids to do physical labor any more. Plus, 157 lbs in weight will hurt anyone, no matter how strong they are.
But the real reason for me doing it is that whenever I start a new project, I use it as an excuse to buy another tool! :)
With that much kWh capacity I would consider going to a 240V split phase inverter and power the entire coach. I was all set to go to 48V with a 10k AIMS split phase inverter in our '91 U300 but then we sold it.
Here is a simple patch panel using 50 amp plugs and receptacles. This makes it easy to connect the inverter in-line with the main breaker panel and allows quick bypass if needed for any reason.
(http://www.foreforums.com/MGalleryItem.php?id=4815)
Peter,
I like your idea.
For the short term, I'm looking to set up the new 48V House bank with 1 Quattro to just be a replacement for the old House bank and Prosine 2.5 inverter. This will allow me to finally get on the road next month.
But, absolutely. Two 48/5000 Quattro split phase 240V is a nice upgrade. But to get there, I need to do a lot more research. One thing I could do with a second Quattro is to have the option to connect that one to a Lithium battery bank if I wanted to. I would just keep the other one with the charge profile for the AGM Firefly bank. Or, most likely, I will just buy another 8 Firefly batteries. Lithium is nice but at half the cost, the Firefly Oasis are a nice alternative.
If I had gone with Lithium for the House batteries, I probably would have never taken them below 20% SOC, even though it is possible. With the Firefly AGMs, I won't take them below 30% SOC. So a Lithium bank would have only provided me an additional 10% DOD. Because of that, I could not justify paying twice the cost for lithium. But, if I were to expand on the current 928 AH Firefly house bank, then the form factor possible with a Battleborn BBGC3 would make it easier to add more batteries. You're limited with where you can mount Group 31 size, as with the Firefly. Those fit nicely in the battery compartment where the 8Ds used to live, but they would take way too much space any other place in the coach. The weight for a Firefly based battery bank per amp is also almost triple that of an equivalent BBGC3.
So, for now and my planned travels, regular Battleborns 100 AH or 270 AH BBGC3 lithiums would have to come down to about $700 for 100 amp-hr battery and about $2500 for BBGC3. They're a long ways from coming down to that price. That probably won't happen for another 5 years as new solid state and other technologies get introduced.
While expanding the House bank, I do have to worry about the GAWR on the front axle. The weight is not going to be a problem with this first bank of 8 OASIS Firefly and one Quattro 48/5000. But, I will need to weigh the coach and see if I can put a second Quattro and second bank of Oasis batteries before I go there.
If it's okay, I would like to reach out to you at a future time and discuss this idea of a 240V split phase system some more.
Look at sokbattery.com their price for a 12 volt 100 amp is $570. There is a dealer in Buckeye, AZ that has sold some and has good feedback.
If I was going to do it today I think I would look at the new AIMS 12kw, this is UL and CSA listed, 120 amp charge, 63 amp transfer switch, 40 watt power saver. One unit, easy install.
12000 watt inverter charger - 12kw 48 volt inverter | AIMS Power (https://www.aimscorp.net/12000-Watt-Inverter-Charger-48-volt-120-240vac.html)
That's a nice unit. But, as you'll read below, the size of that unit may be a problem for mounting into the bay I have selected for an inverter/charger. Also, having just one inverter/charger, instead of two separate units would not make it possible for me to have two different types of battery banks. With two separate inverters, I could have one with an AGM charge profile and the other driving a lithium profile.
Here is another unit I'm currently investigating. The Quattro 48/10000/140 100/100 120V. Yep, overkill for rving. But, here are my plans:
I'll be building a home base in Florida. Hopefully a place with a garage for the bus. I'm thinking that 2 of the 10KW Quattros and batteries in the RV and sticks-and-bricks, along with the 10 KW diesel generator in the bus would serve nicely as backup power for the house in case of grid down. Also, if a future buyer of the RV does not care for all that power and/or weight in the RV, I could move the inverters and some of the batteries into the sticks and bricks.
I'm constrained with the dimensions of the bay where I plan to install the inverters. I would like to install the inverter/charger in the small compartment behind the pass-thru bay. The passenger side compartment on the other side of the wall from were the compressors, inverter and air valves are currently installed. The 8 House batteries are in the storage accessible from that bay.
From the top lip of the back of the Joey bed to the ceiling in that compartment I have 12". From the top of the Joey bed lip to the floor of the bay, I have another 10". I could remove the Joey bed and have at least 22" vertically in that compartment. Alternatively, I could remove the back edge of the Joey bed and cut an appropriate section out of the floor of the Joey bed so the inverters can get to the floor of the bay. I would leave the front and two sides of the Joey bed so I can still use it as a slider. which is nice. I would probably insert a new "rib" in the Joey bed, towards the back, and in front of the installed inverters for rigidity, and to keep stored items away from the inverter section in the back, as needed. In any case, I would temporarily remove the Joey bed from the RV for now so I can finish the install and start using the RV. That modification to the Joey bed would be a future project. With a modified or removed Joey bed, I could mount the inverters vertically on the back wall. I could frame support for the inverters with some bracket that would rest where the Joey bed is currently finding its own support. The width of that bay is 45"
Quattro 48/5000/70-100/100 120V 17.5" X 13.0" X 9.6" 66 lbs
Victron Energy Quattro 48/5000/70-100/100 | Northern Arizona Wind & Sun (https://www.solar-electric.com/victron-energy-quattro-inverter-48-5000-70.html)
Quattro 48/10000/140-100/100 120V 22.6" X 19.2" X 13.6" 128 lbs
Victron Energy QUA483100100 - InverterSupply.com (https://www.invertersupply.com/index.php?main_page=product_info&products_id=185245)
AIMS 48V 12KW 240V 23.3 X 16.3" X 7.9" 174 lbs
12000 watt inverter charger - 12kw 48 volt inverter | AIMS Power (https://www.aimscorp.net/12000-Watt-Inverter-Charger-48-volt-120-240vac.html)
So I still like the idea of a 48V system. I think I'll be able to mount a 48V inverter in the desired bay. In addition, the 8 Firefly Oasis Group 31 batteries will fit nicely into the battery compartment where the 3 size 8D Gel batteries used to live.
Next problem is the conversion from the 48V bank to 12V for the coach.
I could add multiple DC-to-DC 48V to 12V converters. But, the problem with that is that they take a lot of room, they're limited in their wattage, they generate heat and then I would have to worry about paralleling them to get the power that I need for the coach.
What I'm thinking of doing is the following:
1 - Remove the Prosine 2.5 inverter/charger in the coach to use at home with the 3 8D Gel batteries removed from the coach.
2 - In place of the Prosine 2.5, I will install a Victron Multiplus II 12/3000/120-50 2x120. That unit fits nicely in the same place as the Prosine.
Xantrex Prosine 2.5 20.1" X 15.2" X 6.1" 32 lbs
Victron Multiplus II 23" X 11" X 6" 48 lbs
3 - I will then install a relatively small 12V battery bank, either AGM or Lithium to be charged by the Multiplus II. The purpose for that bank would be to supply the 12V needs of the bus. This way, I won't need 48V to 12V conversion.
4 - Only use the Multiplus II to charge the 12V bank. I don't plan to use the Multiplus as an inverter. That 12V bank would be connected to the 12V distribution in the bus. With this setup, the Quattro would essentially just be responsible for the AC power loads of the bus. In addition, the Quattro would also do the pass-thru for the shore or generator 240V AC into the bus and the Power Assist. The Multiplus and 12V bank would just be responsible for the DC loads.
5 - Future Solar MPPT charging for both the 12V and 48V banks.
6 - I still have to figure out the AC power into the Multiplus. I would like the 12V bank to be charged by shore power when available or by the generator when not.
I will probably add a manual switch to connect the output AC from the Quattro to the AC input of the Multiplus as a last resort to charge the 12V bank at a penalty of loss in efficiency.
Question: How many amps minimum should I use for the 12V bank? I would like to boondock and Harvest Host on many days in a given year. I also don't want to have the generator running for more than an hour or two each day.
I'm thinking, at a minimum, 500 AH for the 12V bank? Worst case, I can always pipe the juice from the 48V bank to the 12V bank. Any ideas?
For wiring the 48V bank, I'll use as large a cable as practical and select the length of cabling between the batteries so that I could always rewire the 48V bank into a 12V bank system. This way, I could connect the Multiplus II to it and remove the Quattro 48/10000 if a future buyer of the RV does not care for that expensive setup. Removing it from the RV would also make sense since the Quattro already has the additional purpose of serving as part of the sticks-and-bricks backup power.
But, I'm now thinking that I would just have 1 Quattro in the bus. I think that it makes more sense to have more batteries rather than use space and weight in the RV for a second Quattro. That one 10000 VA would be more than enough to satisfy the AC power needs while boondocking. The 140 Amps of charging from the 48V output of the Quattro, for 2 or even 3 strings of batteries from one Quattro should be plenty. Not sure yet what having a second Quattro in the bus and 240V AC would get me while rving.
I do plan to keep the propane refrigerator for now. Don't see a strong reason to replace it. I have a 2 burner propane stove that the DW prefers to electric. I have Aquahot so that will burn up diesel to take care of heat and hot water while boondocking. So one leg of AC power while boondocking to power at least 1 air conditioner, that should be fine. Time will tell.
A second Quattro setup at the home base, connected in a split phase with the one in the bus would take care of the 240V backup needs of the home base. That second Quattro in the home base may benefit from long lived Lithiums for its bank.
If you do a search you might find the posts of Tim who did the 48 volt set up. The bad news was in the end he couldn't sell the coach as it was too complicated. He listed it for months on the forum.
Follow this thread
48 VOLT SOLAR LITHIUM SYSTEM (https://www.foreforums.com/index.php?topic=29864.msg255169#msg255169)
I read Tim's thread. I wonder how Tim is doing or if he is still out there enjoying the RV life?
But, absolutely, the only reason that I'm considering a battery bank for the RV with more than 20 KW-hr and a 48V 10000 VA inverter is because I want the dual use as a backup power system for the home base.
So, yes, most likely, I would remove the 48/10000 Quattro and about 10 KW-hr of batteries before selling the coach. Most people don't need or want that much weight or expense. But, if a future buyer of the coach wants it with all the goodies, I could leave it all in the coach. But, most likely, the 928 AH from the 8 OASIS Firefly and the Multiplus II 12/3000/120 2x 120 to be left with the coach would be fine for a resale. In that case, I would just need to rewire the Fireflys for 12V operation and connect the Multiplus II and AC pass-thru to the coach.
My planned battery changes may have to wait about a month or two. It turns out Victron and all inverter suppliers that I have checked have the Multiplus II on back order. Worst case, I could continue to operate with the 2 8D Gel batteries still in the coach and with the Xantrex 2.5 for now. Those old 8Ds are not good enough anymore for boondocking, so I will just need to find some local parks with power hookups for now.
Peter well I admire your dedication I really think you're overthinking it a bit. Or should I say overcomplicating it. I understand exactly where you're coming from and what's your wants and needs are. Or at least I think I do. I think your choice of the Firefly batteries is top. I love those batteries or at least the idea of them never having used them myself. On my last sailboat I thought about using those but I used a thin plate pure LED batteries instead using the version at Sears had on their DieHard Marine series. And I do agree that lithiums on for everybody. I'm just not really sold on the 48 volt thing. I'm not even sold on 24 volt. I think it just makes things a little bit too complicated. I have a victron multiplex 3 kw inverter along with 600 amp hours of victron lithium batteries. Along with 1400 watts of solar on the roof and a victron mppt controller I'm able to go 2 to 3 days with normal use and for if I really push it with a little to no sun. That's on a propane less coach. So I use either diesel or electric for everything. Right now I did start the generator because I wanted to run both air conditioners for a couple hours before it cooled off a bit. And I figured I would top the batteries up to around 80% while I was at it. And it's good to run the generator once in awhile to exercise it anyway. I would have liked the Quattro 5K inverter charger but don't usually find that I have a need for it. And at the cost of that baby I think it's Overkill for me.
Anyway I will follow your thread with interest. Good luck and hope you get it worked out. By the way my lithium ion batteries are in the compartment where the splendid washer dryer used to be. It's not where I would have put them, but where are previous owner told AM solar to put them. But they are in a good spot there out of the way of the Bay. I don't have to worry about it being too cold although the heat generated from them sometimes can be a warm. I do have an AC duct that cools that area very nicely.
Bob
Hi Bob,
There are 2 appealing ideas that are possible with the battery setup that I'm thinking about implementing:
1 - I like the idea expressed by many in this forum of having the option of running at least 1 AC while rolling down the road.
2 - A backup power system for my home base in Florida is a must. Sure, a house could always have a diesel or propane generator as well as a tank full of fuel and maybe a Tesla Powerwall setup. But, with the RV parked at the house; the generator, the tank for the diesel and the batteries are already inside the bus. Very convenient. You would just need to add another 48/10000 Quattro and give it its own battery bank at the house to complete a 240V split power backup system for the homestead. That would be almost the equivalent of having 100 Amp 240V split service from the power company into your house.
True, you don't have to go with 48V. A watt-hr is a watt-hr, whether it comes from 12V or 48V. But, the first obvious consequence is that you'll be moving 4 times the current through some of the RV cabling for 12V compared to 48V. The not so obvious is that the 48V Quattro is charging at 140 amps. The 12V Quattro is doing 220 amps while charging. That is 6720 watts of charging for the 48V charger vs. 2640 watts for the 12V unit. That is, it will take you 2.5 times longer to charge the 12V bank than the 48V bank. And, if you were using a Multiplus II 12/3000/120-50 2x120 to charge a similarly sized 12V bank, it would take about 4.5 times as long as with the 48V 10000 VA Quattro. So, charging 12V banks may not be a big deal while on shore power or solar, but annoying and expensive with a generator. Another important and not so obvious fact is that you're not going to get 10000 VA with a 12V inverter. Only a 48V inverter like the Quattro 48/10000 will do that. The reason that is important is because now you could pump both 120V legs of your RV breaker panel with 5000 VA each. You would just be limited with what you can do by the size of the battery bank in the bus and not by the power from the inverter.
Side Note: With the above Quattro feeding both legs of the AC panel you don't have a split setup. In this case, you will have to concern yourself with the sizing for your neutral wire going back to the inverter, since in a non-split system, at worst case, the neutral will be carrying the current of both L1 and L2 hot wires.
DISCLAIMER: I'm not an electrician. I don't even play one on TV. So before following any advice from anyone in here, for any of the entries in this thread, please consult with an actual electrician!.
Here is a quick calculation for the first idea of running at least 1 of the 15000 BTU airs in the bus while driving. Note: I haven't actually connected a watt-meter to the air conditioner to verify this. This is just from past experience with other ACs.
A 15000 BTU air will most likely operate with less than 1700 watts. That's just over 15 amps at 110V. The 1700 watts turns into about 1800 watts because of the efficiency losses through the system. That turns into less than 40 amps out of a 48V battery bank.
One possible setup: A 270 AH 48V bank, taken down to 20% SOC will run that 15000 BTU air for at least 5 hours. Five hours of comfortable temperature and relatively quiet driving. Also, with some solar on the roof you could be very comfortable at Quartzite overnight, without having to run the generator much. I could see running the 10 KW generator early in the morning to pump the batteries in bulk mode for about an hour. The Quattro 48/10000/140 can pump that 48V bank with 140 amps in just 1 hour. Then, for the rest of the day, you would just let the sun take care of absorption charging for the next sunny 5+ hours.
Now, all of this does not come cheap. Unfortunately, to have a battery bank with 270 AH at 48V, which is consistently taken down to 20% SOC means Lithium. That bank (4 BBGC3) and a 48/10000 Quattro will set you back 13+ coach bucks (6/23/2021 pricing).
Update (7/1/2021): I have decided to actually implement and try this 1 AC on while driving. But, not with Battleborn Lithiums, which are about double the price. Instead, 8 Firefly OASIS, set up as 2 strings of 48V and driven by the Quattro 48V/10000/140. That setup is about $10,000 total. About $5000 in just batteries. That is 232 AH at 48V. Taken down to 30% SOC, it means about 4 hours of one of the15000 BTU ACs running while off grid.
While we never run the generator at campsites, if we happen to be traveling where it's hot, the generator might run all day for the ACs while going down the road. For those with dash air, it produces more BTUs that one roof air. Think it's rated at 17K BTU.
Since Q is in January, a little heat at night might be needed rather than AC in the day.
$13K for batteries seems like a bad fantasy to me. We paid $210 total for all six of our AGMs. You can buy a decent Foretravel for $13K.
I noticed last week at June Lake that the only generators running were low noise gasoline generators. The parks are enforcing the 60db limit in some locations, 68db in others (at 50 feet). Our 10Kw is well over 80db at 50 feet.
We have enough solar to run an evaporative cooler and since we live in the West where the humidity is low, the efficiency would be pretty good. Running at night is not possible but most of our summer campgrounds are at high elevation so never hot once the sun goes down. Scott is stuck with oven like temps at LV even at night in summer. No envy here. :D
Pierce
I was poking around the interwebs and here is a very interesting article regarding discharge of AGM batteries that I think ties into this discussion.
AGM battery Depth of Discharge myth busted (https://tab-rv.vanillacommunity.com/discussion/9940/agm-battery-depth-of-discharge-myth-busted)
The "how to lie with statistics" from above leaves out one fact. That fact is as your AGM battery ages with increased cycles, the available ah also decreases. So the articles conclusion is false. If you want best wet deep cycle life total ahs, maybe use BK or gell as the FT came with or the Lifeline gell.
The best source I've found over the years is the Lifetime Tecnical Manual. I've 20 years of experience with using and users of the Lifeline product and the LifelineTechnical Manual below.
For many now Lifepo4 will be their answer to budget, needs, and experience. I'm generally plugged in and have 1800 watts of solar, so AGMs still meet my needs.
Link Sharing (https://linksharing.samsungcloud.com/rHf687GeXnuA)
The "how to lie with statistics" from above leaves out one fact. That fact is as your AGM battery ages with increased cycles, the available ah also decreases. So the articles conclusion is false. If you want best wet deep cycle life total ahs, maybe use BK or Lifeline gel as the FT came with.
The best source I've found over the years is the Lifetime Tecnical manual, I've linked below.
For many now Lifepo4 will be their answer to budget, needs, and experience. I'm generally plugged in and have 1800 watts of solar, so O'Reillys AGMs still meet my needs.
https://www.oreillyauto.com/detail/c/fleet-heavy-duty/battery-accessories/deep-cycle---marine-batteries/220f7dcd7121/super-start-fleet-heavy-duty-battery-group-size-8d/ssbl/agm8dt975
8G8D | MK Battery 12v 225 AH Deep Cycle Gel Cell Battery with Automotive Post (https://www.batterystuff.com/batteries/mk-battery-12v-225-ah-deep-cycle-gel-cell-battery-with-automotive-terminal-posts-8g8d.html)
Half of what you read on the web is not true. For you, other than this false use of facts, do your own research, do not rely on one post or repeated myths, only you know your budget, needs, and experiences.
6-0101F (Lifeline Technical Manual) Final 5-06-19 - Lifeline
(https://lifelinebatteries.com/mcm_resources/lifeline-technical-manual/6-0101f-lifeline-technical-manual-final-5-06-19/)
Making Progress:
1 - I removed the 57.5" X 43.25" X 8" Joey Bed from the bay where the battery compartment is. That Joey Bed is 81.5 lbs.
2 - I removed the left metal framing rib that the Joey Bed was riding on so I could get the remaining 2 8D batteries out.
3 - Using some pry bars purchased at Harbor Freight I pulled the 2 8D batteries out of the lower shelf in the battery compartment. I got one of them charging and powering the bus while parked. Both of them will stay in there for now so I can make it to a campground on my maiden voyage with the bus, while I wait for the Multiplus II. ETA on the Multiplus is end of July. The Xantrex 2.5 will not properly manage the Firefly Oasis charging profile.
NOTE: It goes without saying, make sure you look after your fingers and hand while trying to get those batteries out of the battery box. Too easy to crush them. I came close to doing some damage.
The next thing for me is to clean the battery compartment, rustoleum it and manufacture some frame so I can put a second shelf in there. The one shelf in there will not work for 4 Group 31 batteries. So eventually there will be two shelves of 4 Firefly Oasis AGM batteries on each for a total of 8 AGMs and 232 AH at 48V. They will be connected in two strings of 48V each and driven by the Quattro 48/10000/140-100/100 120V. But, before the Quattro, four of those batteries will be wired as a 12V bank to be driven by the Multiplus. Quattro comes later.
Took the metal 8D battery shelving out of the battery box. That shelving is held in place inside the battery box by 8 Torx screws. The inside of the bottom floor of that shelving is 21.75" (L) X 19.25" (W) with room for 11.5" in height. The top shelf is 20.5" (L) X 10.5" (W) with room for 11.5" in height.
The OASIS Firefly batteries are 13.6" X 6.75" X 9.4".
I put 2 of the 8D batteries back into the now empty battery compartment. Each of them are getting charged by Deep Cycle Chargers. The empty battery compartment is 23.5" (L) X 23.5" (W) X 24.5" (H)
I'll have to build an appropriate 2 shelf box so I can fit 8 OASIS batteries inside that compartment.
I continue to work on my battery setup. Some discussion points:
1 - I have read the manual for the Firefly OASIS G31 batteries in detail. Here are some things that I will be worrying about.
- Manufacturer says a fully charged OASIS has a voltage of about 12.90V.
- They require that the OCV (Open Circuit Voltage) of the battery be above 12.70V before putting them to use in a bank.
- If not at > 12.70V, charge at 14.40 V for 12 hours.
- Obvious recommendations for restraining the batteries and putting boots on at least the "+" terminal. They also recommend at least 0.6" but optimum of 1" of breathing room between batteries. They also recommend mounting the batteries so air can flow underneath them.
- 16 ft-lbs of torque for cabling. Terminals are 3/8-16 UNC.
- It is normal for batteries to gas for first few charging cycles.
- If vents leak acid, wipe with alcohol and torque vent caps to about 1.5 ft-lbs.
- Max. Discharge Current: 0.7 C. Batteries are 116 AH, so about 80 A.
- Max. Charge Current: 0.5 C. So about 58 A. I plan to charge the 48V bank at about 0.4C. The 12V bank will need some more TLC, as per discussion below.
- Bulk phase: 14.4V with temperature compensation until charge current is 0.5A
- Float phase: 13.4V - 13.5V
- The charging profile needs to "reset to bulk phase" if charge voltage is < 12V for 1 minute.
- Periodic fast charging recommended, once per week or at least once a month, if deep discharges have occurred or if the charging has been at less than 0.2C. The recommended fast bulk charge is at 0.4C followed by a 24 hour float at 13.5V.
- Peukerts Constant: 1.07 - 1.12
- Temperature coefficient: 24 mv / degrees C.
- Operating Recommendations
- Battery parameters specified at 77 degrees F.
- If charging below freezing, limit charge current to 0.1 C
- If temperature is about 15 degrees F above 77 consistently it may cut the life of the batteries in half. This is a common problem with lead acid batteries and something I will do something about, if possible.
- Batteries do not have to be fully charged on each cycle for batteries to be protected. This is one of the nice things about the Firefly Carbon mesh technology. But they do need " restoration" now and then.
- Restoration process: From a deeply discharged state, charge at 14.4 V until the charge current gets down to 0.5 A. Then, run a Float charge at 13.5 V for 24 hours. Then, fully discharge to 10.5V and repeat the bulk and float charge cycle once more.
Lots of things above to worry about.
2 - I will have pictures later, but for this discussion, here is what I'm doing to care for those expensive batteries:
For 48V bank:
- I plan to have 1" of plywood (2 pieces of 1/2" plywood), sized 30" (L) X 41" (W) resting on top of the bottom of the 2 metal "L" supports for the two side railings the Joey bed used to slide on. This way I won't need to find any new support points for the weight of the batteries in that bay. A 3/4" piece of plywood resting underneath the 1" plywood and on top of the carpeted floor of the bay will limit the range of the flexing of the 1" plywood while driving. The flexing of the 1" support plywood will be good for absorbing some of the shock while rolling over potholes. The 3/4" plywood just held in place with some Velcro. No need to drill the bottom of the bay for that. The 1" plywood held in place with appropriate bolts, washer/lock washers and nuts, at 4 corner points. The bolts installed through the metal "L" side rails. All plywood will be sealed with MinWax sealer and painted black with some low VOC paint.
- I plan to have a 1/2" standoff underneath the 4 corners of each battery to provide for ventilation under the batteries. Three batteries fit across the 41" width of the plywood when placed end to end. Batteries are 13.6" (L) X 6.75" (W) X 9.4" (H). I will then leave 1" of spacing between two strings of 3 batteries. For now, there will be a total of two string of 4 batteries each for 232 A at 48 V. The Quattro will fit nicely in front of that setup.
- I will buy eyelet screws to go into the plywood and use them with appropriate straps to secure each battery in place.
- Note that the 48/10000/140 Quattro will have no problems supplying a 0.4C of charge to each string of 48V. I have planned for a possible third string in the future.
- I will cover the battery terminals with boots. Good quality marine 4/0 tinned copper cabling and copper lugs will be used throughout.
- I'm still researching the selection of appropriate bus bars, fuses, switches, and Victron family of Smart Shunts, Cerbo GX and Color display.
- For the issue of bay temperature control, I'm looking at something like a Flair Smart Vent and their wireless hockey puck thermostat. The vent could be installed under the sink area in the kitchen and provide a way to maintain the air in the battery bay underneath, as close to 77 degrees as possible, assuming that is what the cabin is running at. A better alternative to the Flair Vent may be simply a unit with built in fans and a thermostat. Something like the $60 AC Infinity AIRTAP T4. I would install that with the finished vent and built in thermostat into the battery compartment. I would then wire that under the kitchen counter, as appropriate.
3 - For 12 V bank
The 6 batteries for the 12 V bank have some unique issues.
- The charger for that bank will be a Multiplus II 12/3000/120-50/50 2x 120V.
- Because that charger is limited to 120A of charging, I will break the 6 batteries into 2 battery banks, each with 3 batteries. Both banks to be isolated from each other by switches, to either combine them or just charge one bank at a time during a "restoration" charge cycle.
- The option to be able to isolate the 2 12V banks is so I can provide a solid 40A of charge to each battery during "restoration" battery charging. Now and then, I could connect an AC to the Multiplus while driving, deeply discharging that bank. So I suppose, sometimes, I could be driving with both ACs on. Once I'm on shore power, I would start the restoration process. I would set the switches so the Multiplus deeply charges just one of the string of 3 batteries. Then do the same for the other 12V bank.
- While restoring one of the 12V battery banks, the other bank is switched so it continues to provide for the 12V needs of the coach. Then, I can switch things so the other bank can be restored. I plan to write myself a check list so I can consistently and correctly complete this process of battery management.
Note: All this is a lot of work in an attempt to give the Firefly batteries a long and healthy life. I suppose Battleborn Lithiums with their built in BMS do not need all this hands on, although they do need some. But then, Battleborns are about twice the cost of the Firefly for similar practical performance. In the end, it's all about doing whatever makes each one of us happy. We all have a budget and priorities on what projects need funding.
Sidenote: Is anyone here planning to go hybrid with a toad? I just found out that Jeep may be releasing a Hybrid version of their Gladiator truck for 2022. Jeep already has a hybrid Jeep Wrangler, their model 4xe. But, I'm looking at the Gladiator truck to use as the toad for better towing capacity and payload with the Gladiator. My current toad, a Jeep Wrangler is getting old and could use replacing. A Rubicon Hybrid Gladiator will not be cheap. So replacing the current toad is an important project needing funding. No need to use some of the limited budget on super expensive Lithiums for now. DWMYH.
- The 6 batteries for the 12V bank will provide a total of about 700 AH for the 12V distribution. They will be mounted in the battery compartment used by FT for the 8D batteries. I will probably remove the access panel from that compartment so those batteries can also live in a cool 77 degree environment.
- Batteries to be strapped, separated by about 0.5" and on standoffs.
The Firefly OASIS batteries are specified for 3600 cycles at a 50% DOD and 1000 cycles at a 20% DOD. I plan to keep both banks above a 30% DOD daily. That should give me about 1500 charge cycles. That's 4 years of daily cycling. Most likely, since I will have relatively large banks, I may get 6 to 8 years out of them. By then, who knows where battery technology will be.
Note: By installing the 48V bank for the 120V needs of the bus inside one of the bays, I could always expand the 48V battery bank. This is because the Quattro 48/10000/140 can handle a lot of charging. The 12V bank with 6 batteries, at about 700 AH should be plenty for the low voltage needs in the bus.
Article on Firefly OASIS: Firefly Carbon Foam Batteries Are Great, But Read The Fine Print (https://www.morganscloud.com/2020/12/04/firefly-carbon-foam-batteries-are-great-but-read-the-fine-print/)
Firefly OASIS Battery Manual: https://www.emarineinc.com/Shared/pdf/Battery/Firefly-Oasis-12V-G31-Users-Manual.pdf
Yep, lots of work. Is it all worth it? Only someone like Socrates could answer such deep questions. Unfortunately, he is still dead!
Preliminary design of custom framing for installation of 6 battery 12V bank. The two 12V banks to go inside the old battery compartment. That compartment at 23.5" X 23.5" X 24.5"
I put enough of the design into a 3D CAD package so I could visualize it and get a list of items to purchase for the build.
1 - The wood battery box will rest on 2 pieces of 22.5" 1 X 2 lumber at the same spot as the support provided for the welded metal box from FT and using the same 8 TORX machine screws (1/4" -by 1") provided by FT. The screws recessed so only 3/8" of thread comes out the bottom of the 1X2 board. This 0.75" vertical offset from the floor of the battery box will keep all the weight on the framing of the RV and not on the in-between RV framing pieces at the bottom of that battery bay.
2 - On top of that will rest a solid wood floor of 1.25" X 5.5" lumber. Four pieces mounted on top of the 1 X 2.
3 - Three batteries will go on top of the 1.25" X 5.5" boards, loaded towards the right of the wood box.
4 - 2 X 4 framing, used as columns for the upper shelf decking, at a height of 10.5" tall will rest on top of the 1.25" X 5.5" flooring. Batteries are 9.4" tall. On top of the 8 columns of 2 X 4 framing there will be 1" plywood for the other 3 batteries. Those 3 batteries will be loaded towards the left wall of the box. This is so I will have room on the right wall, 2nd shelf, for fuses, bus bars, 2 selector switches, shunts, etc.
5 - The 2 X 4 support pieces for the 2nd shelf decking will be reinforced by an "X" pattern of 1 X 2 cross pieces to give the second shelf rigidity (see one sample in one of the 3D pictures). A picture of the empty battery compartment is also attached.
6 - I'm leaving 0.5" along the perimeter of the inside of the battery compartment so air can circulate.
7 - There will be spacing between the batteries for air circulation. There is also space between the 1.25 X 5.5 board pieces. The RV flooring of the battery compartment already has two breathing holes provided by FT. Batteries will be strapped individually by attaching straps to stainless Eyelet screws into the wood flooring.
8 - All lumber will be sealed from moisture and painted with low VOC latex paint.
9 - Other details to be described later.
Some visualization pictures from the 3D CAD attached. The RED surface in one of the pictures represents the flooring in the now empty battery compartment.
Just use treated, ground contact rated lumber and treated deck boards. No need for paint or sealing.
Deck boards are nominal 5/4" but are about 1-1/16". 1" plywood is rare. If the second level is 7/8" 48/24 rated waterproof floor sheathing, on 24" centers you are approaching load limits with 3 - 75 lb batteries and an unsupported front edge, even worse with ony the sides supported. I recall the box is wider than the 22.5 inches between supports at 24" on center. This is not just a static load situation but dynamic loads driving down the road increase stress and deflection. You have to provide a battery hold down as well
Maybe a steel solution would be better.
Or use the box for something else and shorten up the joey bed by a foot or so and put your batteries where the end of the joey bed would have been. This is not an uncommon solution and gets your batteries closer to power connections on the other side of the wall.
All of this would be better done after a year or more of real world experience.
Got to agree with Roger. Steel would be my choice but I also think experience over time is a good teacher.
Pierce
True, except I already had a lot of other lumber around. Have you priced lumber lately?
I'm planning on stocking two pieces of 1/2" plywood. The drawing does not show the complete design. There will be 6 of 2 X 4 on the left side supporting the 3 batteries on the top shelf, about 6" on center. 1 X 2 cross braces will be used to stiffen the deck.
Yes. Batteries will be secured from moving. Front of box will have multiple 2 X 4 dropped in front of the batteries to provide a cage to prevent catastrophic ejecting of batteries into the bay in case of crash.
Part of the bay in front of that battery compartment is already set aside for a 48V bank and Quattro inverter.
The time to plan to enjoy life is Now. Unfortunately, a lot can change in life in a year when you pass the age of 60.
I still plan a lot for today and lots of tomorrows and I'm 78. I figure the fountain of youth vaccine is just around the corner so keep on planning/doing and will keep going to at least mid century.
Pierce
I'm changing how I plan to strap down the batteries. I was going to do ratchet types of straps, but with those straps, it may be required to check them now and then in case they need adjusting.
I have ordered a regular metal battery holder to try out and see how well it may work. An adjustable one so it fits the Group 31 battery. I may have to cut the thread end so it fits in that compartment. The anchor points in the attached picture below, screwed to the wood by the batteries could be used with the straps.
Amazon.com: Uriah Products UV002500 Adjustable, Universal Crossbar, Battery... (https://www.amazon.com/gp/product/B00FDXIK3I/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1)
The rubber bumpers in the picture may work well placed under the 4 corners of the batteries to raise it and help with their cooling.
Roger and Pierce,
Yes. You guys are right. After more thinking about this, steel will indeed be needed for some of the parts in the assembly. The two 0.5" thick support pieces that sit on the RV framed section of the battery bay floor will have to handle about 450 lbs. I would like to make those two bars out of stainless steel.
I'll get in touch with an online machine shop and see if they can manufacture what I need.
I think I'll size the stainless steel bars at 0.5" thick X 1.25" wide X 22.5" long.
Each of those bars will need 5/16 through holes for the 4 Torx screws and 4 threaded holes for mounting the wood flooring. I will also like to recess the Torx screws so the weight from above is on the bars and not the screw heads.
Where do you guys get your machining done?
Until I can get those bars made, I'll install the 12 V banks where the 48V bank will eventually go. It looks like I'll have to get into welding and purchase better metal working tools. ^.^d
Plain steel either painted or powder coated would be fine. Stainless is great for the fasteners. Stainless is tough to saw, drill, etc.
I do all my drilling, cutting, welding here at home. A HF 64 1/2" metal cutting band saw is not expensive and does a great job. Same with a drill press. I did toss the chuck and replaced with a Jacobs chuck.
I bought but tossed a HF powder coating gun and bought a 100Kv unit direct from China for about $350 delivered. Made 3 ovens, one small electric, one out of an RV oven and one is a recycled golf clubhouse stainless commercial range. The powder is really cheap. Easy and fun to do.
Pierce
Three pictures attached.
1 - The metal bolt and bracket for holding down the batteries does keep the batteries from moving. Unfortunately, the distance from the flooring for the batteries to the top of the screw in the bracket is too large for my design of the two shelves to go in the battery compartment. The distance to the top of the screw, including the 1/2" rubber stopper used under the battery to allow for air circulation is 12".
2 - I have attached a picture of the typical battery tray that could be used, But, I won't be using it. I do like that strap and its length, so unless I can buy the strap by itself some place else, I may just buy that package with the strap and trays and just not use the trays in this project.
It's the " NOCO BT31S Group 31 Heavy-Duty Battery Tray, Black"
3 - Two of those straps per battery would work well.
For the 12V battery bank, I'm now planning on a metal 22.5" X 22.5" X 0.5" base or appropriate metal cross bars to go perpendicular to and on top of the two 0.5" thick 22.5" long metal pieces that go on the flooring of the battery bay.
It won't be practical for me to work on that project for now. So, it is back to temporarily mounting the 12 V banks into the bay adjacent to the battery compartment.
Making progress.
The best solution for installing the house batteries in the battery compartment would be a metal frame for them. That may allow up to 8 Grp. 31 to go in there. But, no time for that now. So I took inspiration from Roger and started using some heavier pressure treated wood. ^.^d
I'll be installing a total of 4 batteries in that compartment. The other 5 will go in the adjacent bay. That will provide me with 3 12V banks at 1044 AH. Again, the whole idea of separate banks is so the Multiplus II can fast charge 3 batteries at a time at 40 amps every now and then. Most of the time, all 3 banks will be combined and charged at a slow rate of about 10 to 13 amps each plus whatever charging I get from a future solar setup.
Two straps per battery is good 2 ways:
1 - With just one strap the battery could pivot around the strap. Two straps minimizes the chances of pivoting.
2 - Using straps will necessitate frequently checking them. With two straps, if one is loose before I get a chance to check them, the other one may still be tightly held in place.
You could get 6 Full River DC400-6 L16 sized batteries in that box with room to spare for 1245 amp hr capacity.
Hi Roger,
The battery compartment in my U320 is limited in size. It's 23.5" X 23.5" X 24.5". I don't know, but I suppose 6 of those L16 may fit in that compartment. But, I don't know anything about the Full River batteries. The Firefly have a good track record in boating. Also, the 74 lbs of the Firefly are heavy enough. Now that I'm getting rid of the 157 lbs 8Ds, I don't want to go over 100 lbs per battery ever again.
I'm mounting the Firefly OASIS with spacing between them and underneath to facilitate cooling, as per the manufacturer. They're also about half the price of Battleborn Lithium. Only time will tell how well they work as the House batteries in the RV.
What a great thread this is for learning about the 12 volt electrics of our coaches.
I have not read every entry in this thread and wonder if weight distribution has been considered when changing the location of equipment and batteries. I weighed all four corner of my 1996 U320 and discovered that the passenger side was lighter then the driver side both front and rear. I moved two of three 8D house batteries from driver front to passenger rear. I also eliminated the chassis battery bank from the passenger rear. Three 8D AGM deep cycle batteries provide about 600 amp hours for house and 3000 CCA for starting (Cummins recommends 1800 CCA for M11). This simplifies the 12 volt wiring and has been working for me for 10 years.
I am considering Lithium batteries for house but unfortunately they provide very low CCA so I may have to revert back to house/chassis battery banks before converting to Lithium.
Hi Wyatt,
I haven't looked into the specifics of the weight distribution because I'm only adding about 300 lbs of additional weight in 3 additional Firefly batteries, new inverter replacement, switches, cables and lumber for battery framing. That additional weight gets me about 370 AH more for the 12 V in the coach for a new total of 1044 AH.
The 3 old Deka Solar 8G8D were 225 AH and 157 lbs each. The 9 new Firefly Oasis are 116 AH and 74 lbs each.
Once I get this setup going and the RV fully loaded, I'll put the RV on a scale. That weighing will give me an idea of what I can do for a future 48V battery bank system.
More pictures
Installation moves into the bay.
1 - 4 x 4 framing mounted with bolts into the same support brackets that used to support the Joey bed. The mounting is such that there is no weight on the floor of the bay. All weight is on the 4 corners where there is support from the RV chassis.
2 - Four 4 x 4 cross pieces to support up to 16 of the Firefly Oasis batteries. I still have one of the 8Ds temporarily in the RV until I get delivery of the Multiplus II.
3 - Eventually, there will be a vertical piece of plywood in front of the batteries to support a future Quattro 48/10000. The Multiplus II will most likely go into the same bay where the Xantrex 2.5 is now.
The next work is the installation of 4-position switches, bus bars, shunt, power posts, fuses and battery cabling.
The new Multiplus II from Victron is still on backorder. I cancelled that order. I will use the Xantrex 2.5 with the Firefly Oasis for now.
The attached pictures show the planned wiring for the up to 4 banks, for both the 12V and Ground connections. Those 4 switches will allow me to control how well the Oasis batteries get charged and which banks are in use for the 12V and 120 Vac needs of the bus.
One change I may do to the wiring diagram is to add a second SmartShunt. That is, have a shunt for the 12V distribution ground and another shunt for the ground from the inverter/charger. The reason for this is as follows:
- A shunt dedicated to the inverter/charger may allow me to know when the absorption charge current is down to about 0.5A. Firefly recommends absorption charging at 14.4 V until the current gets down to 0.5A.
- A shunt dedicated to the ground for the 12V distribution in the coach will allow me to essentially have a record of the power needs of the 12V distribution system as I use the coach in the future. This is equivalent to having a watt-meter for that circuit, except that I may be able to get a lot more historical data with the Victron App that works alongside with their SmartShunt.
I still have to finish reading the exciting 120 page manual for the Xantrex, so I still don't know if it would be worthwhile or useful to spend money on a second shunt.
All wiring for the batteries and up to the last bus bar for the grounds and the fuses for the 12V are 4/0 quality tinned copper marine cable with ratings at 105 degrees C dry and 75 degrees C wet. For now, I plan to continue to use the existing wiring provided by FT for connecting from the House battery bank to the inverter and to the 12V distribution system.
4/0 cabling bought from Amazon, but supplied by Common Sense Marine (https://www.commonsensemarine.com/page.php?page=marine_wire_list.html&osCsid=7tl6fqpllt3udov39u69ipjag6)
The Xantrex 2.5 can charge at 100A, depending on the configuration for the total amp-hours for the banks getting charged. Since the two 4-position switches shown above provide for controlling 4 battery banks, I plan to have 3 banks of 3 batteries each using the Firefly Oasis and the 4th bank using two of the old 8D batteries that used to be in the RV. That will give me a total of 1494 AH at 12V. For now, that will provide for both the DC and AC distribution for the bus.
By connecting 2 of the Deka 8Ds in parallel as a separate bank, it allows the Xantrex to charge them with 50 Amps each. For the other 3 Oasis banks, I could charge them at a maximum of 33 Amps per battery. With some solar in the future, I should have enough charge current to satisfactorily do the periodic restoration of those batteries, as recommended by Firefly.
I think this setup will work well for the following reasons:
1 - I should be able to have at least 1 AC unit running while driving for 4 or 5 hours with plenty of spare power for microwave, coffee maker, etc. Finally, no need to run the generator while on the road.
2 - At 100 Amp charging, the batteries will be fully charged relatively quickly while plugged into shore power at an RV park and ready for the next drive down the road, even if the stay is just one night. In addition, if staying at a Thousand Trails park, the electric for it should be free at some parks.
3 - Camping overnight at a Harvest Host should be very doable with all 110V and 12V needs covered.
Note the following: This setup is not as practical for boondocking for multiple days as an equivalent KW-hour 48V battery bank would be. This is because with the 12V battery bank and the Xantrex 2.5, we're limited to 1200 W of charging. The generator may be capable of putting out somewhere between 8 KW to 10 KW continuously, but at 1200 W of charging, I would need to run it for up to 15 hours to fully charge the batteries from empty. With the same 18 KW-hr worth of batteries, but set up as 48V banks and getting charged at 140 Amps from a 48/10000 Quattro, it would only take about 2.5 hours for the generator to fill them up. That is the beauty of 48V systems compared to 12V. Faster charging and more effective use of large generators.
Because of this charge current limitation for 12V battery banks and their chargers, I will try to find out the actual 12V power needs of the bus over the next year or so. Then, I could split those 18 KW-hr of batteries into an appropriately sized 12V set of banks and use the remaining batteries with a 48V bank setup along with a future installation of the 48/10000 Quattro to meet the 120 Vac needs. This would allow for more efficient use of the generator when off grid for multiple days at a time.
For boondocking: The future 48V bank charging at 140 A = 6720 watts. The 12V bank charging at 100 A = 1200 watts. So the two future banks together will be charging at about 8 KW. That number would be a good use of the 10 KW generator to bulk charge the batteries for a couple of hours early in the morning. Then, let solar finish charging with an absorption charge. Discharge starts late in the afternoon and night. Next day, rinse and repeat.
Ground wiring updated. Two SmartShunts used. One for the 12V distribution. The other for the inverter/charger path.
Tools of the trade.
- Betooll J40 Cable Cutter
- Jokari Model 10160 Cable Stripper
- Tempco Industrial TH1818 Cable Terminal Crimper
- Seekone Heat Gun SDL-2816
This is the weekend I get this done.
1 - I've decided to just have 3 batteries inside the battery compartment. That simplifies the wiring for the banks. Bank 1 will be inside the compartment. The other 3 banks in the storage bay.
2- On the back of the picture, you'll see the power post and the 350 Amp fuse. One set up for the 12V distribution from the batteries to the bus. The other for the 12V connection to the Inverter/Charger.
3 - On the right in the picture I have the ground bus bar and the two Victron SmartShunts.
Git-R-Done!
Battery bank 1 charging.
1 - I disconnected the AC in to the inverter and wired in a 20A line from the house. I set the switches in the Xantrex 2.5 as follows:
Switch 1
1 - DOWN (GEL setting, which works for AGM as well)
2, 3, 4 - Not Used
5, 6 - Both DOWN for Warm 50 to 80 degrees Farenheit setting. Not sure yet if it would make sense to set these differently.
7, 8 - UP for Load Sense Disabled. I may change this setting later.
Switch 2
1 - UP for audible alarm
2 - Not Used
3, 4 - DOWN for 30 A input
5 - DOWN
6 - UP
7, 8 - DOWN. The setting for 5, 6, 7 and 8 tell the charger that there is more than 1400 AH of batteries. This forces the charger to pump at maximum of 100 A.
2 - Three batteries for bank 1 for 348 AH. The batteries started at 12.7 V for OCV. Fully charged is around 12.9V for the Firefly OASIS.
3 - VictronSmart Shunt is reporting charging at just over 14V at about 15 A.
4 - The four 4 position switches are mounted on 1/2" plywood. I have added two hinges and a latch to the switch assembly. The hinged setup will allow me to get access to that battery compartment.
5 - In the picture showing the wiring inside the compartment, in the back, the right side of the lower fuse is connected to the 12V wiring for the Inverter/Charger, cable B4. The cable ground from the inverter is cable B10. That is connected to the system ground side of the SmartShunt. The upper fuse is for the 12V distribution to the RV. The output from that fuse will eventually be wired to cable B11. The 12V distribution ground, cable B8 will then be connected to the system ground side of the upper SmartShunt dedicated to the 12V distribution.
6 - A battery ground from each bank will go to the bus bar. That bus bar is already connected to the Battery side of both Shunts.
7 - While that bank charges, the next work is the framing for mounting the switches.
I thought the closest setting for AGM was the wet setting. I know it is with the Xantrex SW 3012
I have the Xantrex 2.5. The switch 1 settings for the battery type are on pages 25 and 26 of manual. With that inverter, I can only set for either Flooded or Gel. On page 25 of manual, "Sealed batteries should be charged as gel batteries even though they may have a liquid electrolyte."
I just finished testing the 12V switch for bank 1. I had both the inverter charging bank 1 and the same bank providing 12V to the bus. So the setup seems to be working as expected.
Both Shunts are running and reporting voltage/currents. I still need to inspect what the Shunts are saying with a read of the actual currents.
I'm going to investigate mounting a thermostatically-controlled fan for that battery compartment. It's going to get hot in there when the switch panel is in the upright position. I have the temperature sensor from the Xantrex connected to the ground for one of the batteries in that compartment. I figure that out of all 4 banks, that one in there will be at the highest temperature.
Second bank of 3 Firefly installed in the bay. Charging nicely. The two 8Ds are in the bay as well but not connected yet.
Third bank of Firefly installed and fully charged. The 8Ds will be wired this weekend.
The pictures show the battery terminal connectors I had bought for the 8D cabling. Update: I threw them away. They are really bad quality. Not much copper on them. Roger is right, see his thread below. Buy one of those instead. I'll keep the picture of the one not to buy here so no one else makes that mistake.
Perhaps a better choice is military style connectors.
Amazon.com: Ampper Military Spec Battery Terminal End, Top Post Battery... (https://amazon.com/Ampper-Military-Battery-Terminal-Vehicles/dp/B07JJKVHD1/ref=sr_1_3?crid=1A0TMJMRTGSS9&dchild=1&keywords=military+battery+terminals+heavy+duty&qid=1628721731&sprefix=Military+batt%2Caps%2C263&sr=8-3)
Or these, maybe longer bolts, three lugs max in any case.
Amazon.com: A-Team Performance Military Style Top Post for Dual Battery Lead... (https://amazon.com/Team-Performance-Military-Terminal-Positive/dp/B07FCWV4VZ/ref=sr_1_5?crid=1A0TMJMRTGSS9&dchild=1&keywords=military+battery+terminals+heavy+duty&qid=1628721731&sprefix=Military+batt%2Caps%2C263&sr=8-5)
Yep. Those are most definitely better quality than what I bought. Threw mine away and bought the military type that Roger recommended.
All set. All 4 banks installed. Last House bank and Chassis batteries charging now.
Big test next week. I plan to have 1 AC running from the 4 banks without running the generator on my first leg of a trip to FL. That first day will be a five hour drive on Wed. 8/25 from NW New Jersey to Winchester VA. I expect those batteries to handle the AC fine for those 5 hours. Two days later, two Harvest Host sites for two consecutive days in GA. Obviously, some generator help will be needed for that stay.
Refrigerator will be running on propane. While driving, the engine will warm the water. Off grid, the Aquahot will be on diesel. I'll turn the AC off if I need to make coffee, burn bread or run the microwave at a rest stop. At 2500 Watt, the Xantrex 2.5 is really only good to service 1 AC and not much more.
It was a lot of work to get to this point. I'm not happy with how a few things turned out. For example, the location and 4/0 wiring for the four 4-position switches makes it impossible to set the switch assembly vertical. No big deal. I'll change that wiring at a future time. The plan is to keep track of how much power the Chariot needs for 12V power. The SmartShunts will help to figure that out. Then, at a future time, the battery banks will be split up between 12V banks for DC needs and 48V banks for 120Vac needs. At that time, the switches will be repositioned and rewired. For now, the setup is ready for use.
I used the Flojet Maserator model 18555 000 for the first time to empty the tanks. Seventy five feet of 3/4" waste line. It worked great.
I couldn't get the Dometic to start on gas. I tried and tried, nothing. I turned on the gas burners in case it was air in the propane lines. Nothing. I tried running from 120Vac, nothing. I wasn't getting 120V to plug in the back of the refrigerator. Panel breaker was fine. Just weird. I checked both fuses from the back of the refrigerator, they were fine. I ran a direct 120 Vac line from the sticks and bricks and connected the black plug from the refrigerator to it. The refrigerator started on 120Vac. I waited 5 minutes. I switched the refrigerator from electric to gas. I heard a bang, louder than usual. It stayed running on gas. What I think may have happened is water got in there. Yesterday, I finished pressure washing the RV and I may have gotten some water in there. I tried to be careful with the pressure washer around the outside by the refrigerator, but some water may have gotten in there. But, other than messing with the electric, I don't know how water would interfere with the works for propane. But, all is well that ends well.
Git-R-Done!
When did Aqua Hot switch to propane from diesel?
Testing running 1 AC unit off the inverter
I have the coach off-grid right now and with the inverter on. It seems that both AC units on the U320 are running off 20A breakers and plugged into the phase in the Main electrical panel that is not connected to the output from the inverter. The Xantrex 2.5 is right now just inverting for one leg of the main panel.
I have a 50A subpanel with just one of the phases. That one has the breaker for the microwave. The microwave is on, getting power from the inverter, which tells me that circuits that should run off the inverter should go into that subpanel.
Unfortunately, I still need to get the toilet running before I get on the road tomorrow. I may not have time to get to the AC panel today to verify this and to do the required wiring.
Got front air conditioner running off the inverter. I finally got the toilet issue fixed.
I moved the 20A breaker for the front air conditioning unit, from the Main panel to the subpanel that is connected to the output of the Xantrex.
It draws about 12.6 A at 119Vac. That's 1500 watts. That's about 125 A at 12V. For the 1490 AH battery bank, for 5 hours that's about 40% DOD.
Ready to rumble tomorrow.
With inverter efficiency you will be at about 1800 watts load on the batteries. I would measure inverter current draw with fan on high - on my '91 A/C was running about 150 amps on my inverter and alternator going down the road. Be sure inverter has adequate ventilation running 1800 watts continuously. I added a blower in my inverter bay vented to the outside.
Fasco 50747-D600 Centrifugal Blower with Sleeve Fasco 50747-D600 Centrifugal Blower with Sleeve Bearing, 3,200 rpm, 115V,... (https://www.amazon.com/dp/B0099CFJW4/ref=cm_sw_r_apan_glt_fabc_3B7MBGBJC6HHES8VPVCK)
POWERTEC 70129 PVC Dust Collection Hose POWERTEC 70129 PVC Dust Collection Hose (2-1/2" x 10') | Flexible Clear Vue... (https://www.amazon.com/dp/B00HHBSH78/ref=cm_sw_r_apan_glt_fabc_G8XTTFYCEQ6F1TNRESK1?_encoding=UTF8&psc=1)
POWERTEC 70127 2-1/2 Inch Key Hose Clamp Amazon.com: POWERTEC 70127 2-1/2 Inch Key Hose Clamp | Stainless Steel 2.5"... (https://www.amazon.com/dp/B00EWO4LIC/ref=cm_sw_r_apan_glt_fabc_GPHD9WCNWPXTQC2CDXZT?_encoding=UTF8&psc=1)
Successfull and very satisfactory test. At least for the way I plan to use the coach. I'll have more details later. I'm entering this message with the phone. Painful for when typing a lot. So I'll keep it short for now.
Ran 1 AC with the inverter from 3 battery banks totaling just over 1000 AH. The other bank switched and dedicated to 12V needs.
AC running at full blast for 4 hours. Most of the time, inverter was drawing about 180 amps. Just over 2 kw. Total draw of 758 AH. Battery voltage went down to 36% SOC. Voltage down to 11.79V. I stopped the test after the Xantrex control panel started beeping with a blinking red light.
With the 1 AC running and a 12V fan on the dashboard it was a very comfortable ride. Didn't even have to run dash AC. Temperatures in TN were in the high 80s with over 93% humidity.
That night, got to a campground and batteries were nearly charged full by next morning.
I wonder how much I'm saving by not having to run the diesel generator?
Good first day...
10K generator fuel consumption at full load is estimated at 0.5 gl/hr. So if you spent an extra $1500 to be able to use your batteries and inverter to run an AC then it will take 1000 hours at current fuel prices to break even. Not including the significant wear and tear on your batteries and inverter. Discharging your batteries to 36% SOC and 11.8v won't help with battery lifetime.
I wonder if an hour of AC (both) on generator (and charging batteries) when you start out and cooling demands are highest would get you more time with less battery demand once the coach is cooled down.
Peter,
From your profile picture I know that you are still relatively young.
My guess is, that you during your lifetime will never financially break even, if you do a rigorous financial cost/benefit analysis.
But a financial analysis does not measure the peace of mind knowing you have a reliable system, and most importantly, does not measure the satisfaction you got from taking your considerable subject knowledge and applying it.
And it also does not measure the value of information you dispursed to your fellow Forum members.
I learned all sort of things following your post.
Regards
Klaus