Motorhome with 1 solar array and 2 battery banks

[learning all the time]

I am confident this has been answered somewher but seem to find 2 SCC to 1 battery bank and not really two batteries. While my motorhome is parked between trips I want to keep the engine battery charged. Using my extesive skills and sparing no expense on this drawing I want to use a splitter with MC4 connectors before the controllers. As you see from my top notch drawing, I am running 500w of solar to a 40 amp mppt. I want to split this line and charge my lead acid engine battery with a seperate pwm charge controller. I usually plug in with a battery tender but hate the cords laying everywhere. While the vehicle is parked, I turn off the solar with a kill switch so as to not keep my LifePo4 at 100% in storage. Basically, I have everthing laying in my garage so that is how parts were selected. I am wondering if this is possible or will it create issues? I do have an option of just unplugging 1 panel and running a line that way.

 

[snoobler]

Assuming you are in storage mode and using no power whatsoever, simply divert all charging to the chassis battery. LFP will retain charge for many months. I recently checked cells I had charged a year prior, and they still retained 95% of their charge.

Your proposal is fine as long as you never have the panels joined to both charge controllers. Shouldn't harm anything, but the PWM will kill the performance of the MPPT.

 

[learning all the time]

OK awesome. Thanks Snoobler. If the only issue is an arguement between the two controllers I can add another kill switch to the engine battery solar line as it only needs to charge while in storage. I do believe I have one laying in the garage.

All my house batteries have wireless connectivity so I check it quite a bit. It will be some time before they need any sort of charge.

 

[willo]

My victron smart solar controller is trivial to adjust charging levels. When storing earlier this year, I just cut down my max charge voltage. That way the cells still get a little bit of service charge if needed.

Honestly, I'd just tie one panel to your 10a PWM controller and be done with it. If you're in a snowy area, you may want to mount that panel on the side so it doesn't get build-up on it.

 

[clarkpeacock]

Assuming your system is 12v, you could fit of these

CSB2 - CBE

Electronics for Caravanning and Boating

www.cbe.it

It's provides a 4A trickle charge to the engine battery when the leisure batteries are charged

Saves messing with the solar!

 

[learning all the time]

Assuming your system is 12v, you could fit of these

CSB2 - CBE

Electronics for Caravanning and Boating

www.cbe.it

It's provides a 4A trickle charge to the engine battery when the leisure batteries are charged

Saves messing with the solar!

I am not 100% sure what this is? I think its a dc to dc charge controller. My main problem with these systems is they charge the LifePo4 to 100% then move on to the battery. It can be several months between trips I take and my understanding is that LifePo4 does not like to store at 100% which is why I have a kill switch on it. Other than that it looks cool and that company seems to have some other interesting products so thank you for the information as its still an avenue I could travel.

 

[learning all the time]

My victron smart solar controller is trivial to adjust charging levels. When storing earlier this year, I just cut down my max charge voltage. That way the cells still get a little bit of service charge if needed.

Honestly, I'd just tie one panel to your 10a PWM controller and be done with it. If you're in a snowy area, you may want to mount that panel on the side so it doesn't get build-up on it.

I live in sunny Southern California. I have had enough midwestern winters for a lifetime lol. My solar panels have the problem of all my neighbors having their lawns mowed on different days so cleaning the dirt is a near impossible chore.
My only obstacle with this is running the line cleanly as I have and still am exploring this. I don't want to punch a hole in my roof just for a engine battery line. I really do like the set it and forget it and never worry about it option though. Thank you for your help.

 

[willo]

I live in sunny Southern California. I have had enough midwestern winters for a lifetime lol. My solar panels have the problem of all my neighbors having their lawns mowed on different days so cleaning the dirt is a near impossible chore.
My only obstacle with this is running the line cleanly as I have and still am exploring this. I don't want to punch a hole in my roof just for a engine battery line. I really do like the set it and forget it and never worry about it option though. Thank you for your help.

Heh, well, a side panel may be handy then too - quick to clean off when needed.

I added a raspberry pi running victron code - if you have internet handy you can have it upload stats to their free portal and add alarm alerts. My camper is a good half hour away from me down a mountain when I'm storing, so I'm finding it extremely nice to be able to monitor things. (I have a an LTE access point in my rig)

 

[clarkpeacock]

I am not 100% sure what this is? I think its a dc to dc charge controller. My main problem with these systems is they charge the LifePo4 to 100% then move on to the battery. It can be several months between trips I take and my understanding is that LifePo4 does not like to store at 100% which is why I have a kill switch on it. Other than that it looks cool and that company seems to have some other interesting products so thank you for the information as its still an avenue I could travel.

Kind of a dc-dc charger, but it only starts trickle charging the engine battery when the leisure batteries exceed 13.6v and stops again when they drop to 12.5v, so does actually make them work a bit. I have one on my camper van that works really well, but all AGMs, so not sure how it would work with LifePo4