Battery Updates and Charging - Solar - Inverters

Topic: Battery Updates and Charging - Solar - Inverters (Read 6272 times) previous topic - next topic

Re: Battery Updates and Charging - Solar - Inverters

Reply #25 – May 01, 2021, 09:34:28 am

Quote from: cucotx – April 29, 2021, 09:50:45 am

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...

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.

Re: Battery Updates and Charging - Solar - Inverters

Reply #26 – May 01, 2021, 12:06:19 pm

Quote from: prfleming – May 01, 2021, 09:34:28 am

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.

Re: Battery Updates and Charging - Solar - Inverters

Reply #27 – May 01, 2021, 01:03:55 pm

Here is a previous post with some ideas.

Homemade B2B charger project

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.

Re: Battery Updates and Charging - Solar - Inverters

Reply #28 – May 01, 2021, 02:22:57 pm

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.

Re: Battery Updates and Charging - Solar - Inverters

Reply #29 – May 02, 2021, 01:33:45 pm

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.

Re: Battery Updates and Charging - Solar - Inverters

Reply #30 – May 02, 2021, 06:23:18 pm

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?

Re: Battery Updates and Charging - Solar - Inverters

Reply #31 – May 02, 2021, 09:57:31 pm

Here is one source, search for Delco 61003345

Delco Remy 55SI 430A Alternator - 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!

Re: Battery Updates and Charging - Solar - Inverters

Reply #32 – May 02, 2021, 10:04:20 pm

Here is the 55SI brochure

Re: Battery Updates and Charging - Solar - Inverters

Reply #33 – May 02, 2021, 10:37:38 pm

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.

Re: Battery Updates and Charging - Solar - Inverters

Reply #34 – May 03, 2021, 01:34:27 am

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".

Re: Battery Updates and Charging - Solar - Inverters

Reply #35 – May 03, 2021, 08:36:40 am

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...

Re: Battery Updates and Charging - Solar - Inverters

Reply #36 – May 03, 2021, 09:14:22 am

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.

Re: Battery Updates and Charging - Solar - Inverters

Reply #37 – May 03, 2021, 09:41:41 am

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.

Re: Battery Updates and Charging - Solar - Inverters

Reply #38 – May 03, 2021, 10:32:06 am

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.

Re: Battery Updates and Charging - Solar - Inverters

Reply #39 – May 03, 2021, 10:43:05 am

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.

Re: Battery Updates and Charging - Solar - Inverters

Reply #40 – May 03, 2021, 11:08:34 am

Here is the Blue Sea wire chart. 4/0 both ways (B+ and Gnd) should handle the 55SI output.

Re: Battery Updates and Charging - Solar - Inverters

Reply #41 – May 03, 2021, 11:28:49 am

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

Re: Battery Updates and Charging - Solar - Inverters

Reply #42 – May 03, 2021, 12:12:21 pm

Now that right is some serious cabling

Re: Battery Updates and Charging - Solar - Inverters

Reply #43 – May 03, 2021, 12:48:38 pm

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.

Re: Battery Updates and Charging - Solar - Inverters

Reply #44 – May 03, 2021, 02:27:45 pm

Quote from: prfleming – May 01, 2021, 01:03:55 pm

I believe the Sterling B2Bs have an ignition turn-on option so wouldn't need a separate VSR.

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?

Re: Battery Updates and Charging - Solar - Inverters

Reply #45 – May 03, 2021, 03:18:57 pm

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.

Re: Battery Updates and Charging - Solar - Inverters

Reply #46 – May 03, 2021, 05:02:55 pm

Quote from: Roger & Susan in Home2 – May 03, 2021, 11:28:49 am

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

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.

Re: Battery Updates and Charging - Solar - Inverters

Reply #47 – May 03, 2021, 06:14:14 pm

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

Re: Battery Updates and Charging - Solar - Inverters

Reply #48 – May 03, 2021, 06:57:44 pm

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.

Re: Battery Updates and Charging - Solar - Inverters

Reply #49 – May 05, 2021, 10:26:39 am

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.

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