Battery Updates and Charging - Solar

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

Battery Updates and Charging - Solar - Inverters

April 29, 2021, 09:50:45 am

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?

Re: Battery Updates and Charging - Solar - Inverters

Reply #1 – April 29, 2021, 10:34:46 am

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

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.

Re: Battery Updates and Charging - Solar - Inverters

Reply #2 – April 29, 2021, 11:25:02 am

My generator comes off the house batteries. I can tell as the lights inside dim when the generator starts.

Re: Battery Updates and Charging - Solar - Inverters

Reply #3 – April 29, 2021, 12:14:12 pm

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.

Re: Battery Updates and Charging - Solar - Inverters

Reply #4 – April 29, 2021, 01:14:15 pm

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.

Re: Battery Updates and Charging - Solar - Inverters

Reply #5 – April 29, 2021, 01:32:50 pm

Quote from: cucotx – April 29, 2021, 01:14:15 pm

Connecting the alternator directly to the AGM batteries means those batteries never charge fully.

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

Re: Battery Updates and Charging - Solar - Inverters

Reply #6 – April 29, 2021, 11:14:12 pm

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

Re: Battery Updates and Charging - Solar - Inverters

Reply #7 – April 30, 2021, 09:13:45 am

Quote from: Chuck & Jeannie – April 29, 2021, 01:32:50 pm

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

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.

Re: Battery Updates and Charging - Solar - Inverters

Reply #8 – April 30, 2021, 10:08:10 am

Quote from: cucotx – April 29, 2021, 01:14:15 pm

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.

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

Re: Battery Updates and Charging - Solar - Inverters

Reply #9 – April 30, 2021, 10:21:03 am

Quote from: cucotx – April 30, 2021, 09:13:45 am

I was referring to the higher absorption voltages that AGM batteries need to fully charge. Higher than alternators can supply.

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

Re: Battery Updates and Charging - Solar - Inverters

Reply #10 – April 30, 2021, 11:53:34 am

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.

Re: Battery Updates and Charging - Solar - Inverters

Reply #11 – April 30, 2021, 12:18:07 pm

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

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.

Re: Battery Updates and Charging - Solar - Inverters

Reply #12 – April 30, 2021, 01:19:28 pm

Quote from: cucotx – April 30, 2021, 11:53:34 am

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 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.

Re: Battery Updates and Charging - Solar - Inverters

Reply #13 – April 30, 2021, 01:31:08 pm

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.

Re: Battery Updates and Charging - Solar - Inverters

Reply #14 – April 30, 2021, 01:48:12 pm

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.

Re: Battery Updates and Charging - Solar - Inverters

Reply #15 – April 30, 2021, 02:26:11 pm

"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.

Re: Battery Updates and Charging - Solar - Inverters

Reply #16 – April 30, 2021, 03:04:40 pm

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?

Re: Battery Updates and Charging - Solar - Inverters

Reply #17 – April 30, 2021, 03:22:16 pm

Quote from: cucotx – April 30, 2021, 03:04:40 pm

...stock alternator LN model A0014884JB...would a good replacement be Delco Remy 40SI?

Prestolite - Leece Neville

Delco 40si 240 Amp Alternator, Sterling ProSplitR Installation

Re: Battery Updates and Charging - Solar - Inverters

Reply #18 – April 30, 2021, 03:45:45 pm

Quote from: folivier – April 30, 2021, 01:31:08 pm

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.

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.

Re: Battery Updates and Charging - Solar - Inverters

Reply #19 – April 30, 2021, 03:50:21 pm

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.

Re: Battery Updates and Charging - Solar - Inverters

Reply #20 – April 30, 2021, 03:57:17 pm

Quote from: cucotx – April 30, 2021, 03:45:45 pm

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.

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.

Re: Battery Updates and Charging - Solar - Inverters

Reply #21 – April 30, 2021, 04:08:02 pm

Quote from: Tommy D – April 30, 2021, 02:26:11 pm

I had 200watts and it didn't keep up during the dreary winter days with no sun.

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.

Re: Battery Updates and Charging - Solar - Inverters

Reply #22 – April 30, 2021, 04:17:28 pm

Quote from: Chuck & Jeannie – April 30, 2021, 03:57:17 pm

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.

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.

Re: Battery Updates and Charging - Solar - Inverters

Reply #23 – April 30, 2021, 08:10:06 pm

Quote from: cucotx – April 30, 2021, 04:17:28 pm

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.

Might get some ideas from this post with Rogers suggestions on hooking up a B2B
Another lithium upgrade.

Re: Battery Updates and Charging - Solar - Inverters

Reply #24 – April 30, 2021, 08:19:24 pm

Quote from: cucotx – April 30, 2021, 04:08:02 pm

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.

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...
And house batteries
Amazon.com : Blue Sea Systems HD-Series Heavy Duty On-Off Battery Switch,...

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