Doubt about Solar Panels and the Lithium Battery

[Sid]

Hi,

We just bought our first Montana. 2022 Montana HC 335BH.

It came with a solar panel and a lithium battery. We had other trailers in the past, but never with this setup. The Solar controller is a Victron MPPT 75 / 15.

While keeping at the storage, should I turn the battery Off ? I m leaving On during the summer because the panels keeping the battery charged.

And, as I live in Colorado, should I remove this lithium battery from the trailer during the winter?

Thanks for your support.

Sid
2022 Montana HC 335BH
2017 F-350 Lariat

[artfuldodger]

Yes I would leave the trailer without power in storage and definitely take the lithium batt home to heat. Lithium doesn,t do well in sub freezing temps and should never be charged below 32°.

[artfuldodger]

I forgot to wish you a warm welcome to the forum and congratulations on your new Monty! Check out YouTube to learn how to maintain lithium batts as they are more finicky than lead acid or AGMs.

[Sid]

Originally Posted by artfuldodger

I forgot to wish you a warm welcome to the forum and congratulations on your new Monty! Check out YouTube to learn how to maintain lithium batts as they are more finicky than lead acid or AGMs.

Thanks. Everything is new for me here. Lots of valuable information!

[scottz]

I also live in Colorado. In the winter, I keep my trailer plugged in (inside, but unheated storage) but I switch off the battery disconnect (my install) so the batteries are not charging all winter. I do not remove them. No issues yet after two winters with lithium batteries. I just have to remember to turn the switch back on before trying to move the slides or jacks; the converter does not have the juice to do it.

[Sid]

Originally Posted by scottz

I also live in Colorado. In the winter, I keep my trailer plugged in (inside, but unheated storage) but I switch off the battery disconnect (my install) so the batteries are not charging all winter. I do not remove them. No issues yet after two winters with lithium batteries. I just have to remember to turn the switch back on before trying to move the slides or jacks; the converter does not have the juice to do it.

Thanks Scott.

I have to leave my trailer outside. My concern is if I switch off the battery, and the solar panels keep charging it, the battery could be dead soon by overcharging as it will not have a minimum source to discharged it (like the smoke detectors...).

[Daryles]

Originally Posted by Sid

Thanks Scott.

I have to leave my trailer outside. My concern is if I switch off the battery, and the solar panels keep charging it, the battery could be dead soon by overcharging as it will not have a minimum source to discharged it (like the smoke detectors...).

Your MPPT controls the charging of the battery from the solar panels.
No worries about over charging as long as the MPPT is setup correctly.
HOWEVER...
Lithium batteries do not like to be charged in FREEZEING temperatures..

Here is a very good article about it

How to find happiness with lithium batteries
https://www.solacity.com/how-to-keep...tteries-happy/

If you do any boondocking at all I would add more batteries, panels and upgrade the MPPT to a 100/50 or better depending on how many panels you add.

[rames14]

We also live in Colorado. I left my batteries in and connected. Hit -12 over the winter without issue. I have it plugged into my 50 amp, but 15 amp will be fine. Lithium batteries aren’t damaged by the cold, they just don’t charge below freezing. If they’re Battleborn’s, they should have internal heaters.

[Sid]

Originally Posted by Daryles

Your MPPT controls the charging of the battery from the solar panels.
No worries about over charging as long as the MPPT is setup correctly.
HOWEVER...
Lithium batteries do not like to be charged in FREEZEING temperatures..

Here is a very good article about it

How to find happiness with lithium batteries
https://www.solacity.com/how-to-keep...tteries-happy/

If you do any boondocking at all I would add more batteries, panels and upgrade the MPPT to a 100/50 or better depending on how many panels you add.

Thanks for your valuable information. I am more confident now about the solar panels and lithium batteries.

[PNW Fireguy]

Ok just a short add:
1. All drop in LiFePO4 batteries sold in the US have a BMS. The BMS will not allow over charging by design.
2. Check your specific battery specs but many LiFePO4 drop ins allow discharging well below freezing.
3. When temps are mentioned for charging or discharging we are talking about the physical cells within the battery case not ambient temps.
4. Again check your specific battery specs but just about every BMS on the market (minus gen1 Chins) has low temp cutout functionality.

[artfuldodger]

There are others that do not have low temp functionality on the low price end such as Amperetime. I bought them and learned this after installation. Luckily my Solar Controller monitors batt temp and shuts down charging at 32°.The point is OP, is that lithium batts require more thought than lead acid or AGM.

[Sid]

Thanks again for the info.

[Garymyro]

I Live in Alberta where the temps get to -30 and sometimes colder in the winter. I have 2 lithium batteries in my 2020, 3120 Montana with solar and I leave them on with the main power to the trailer off. They survived 2 winters just fine. I do not take them out and have 2 fully charged batteries in spring when I go out.

[Foldbak]

Welcome to the MOC Sid

[artfuldodger]

Garymyro, not to hijack the post but perhaps your battery brand has included a BMS with cold temp monitoring and shut down. Without that feature all the experts say do not charge below freezing. Most lithiums do have that.