Lithium auxiliary battery and cold weather charging

jimbob394

New member
Hey guys,

I have a rather particular question that I'm just trying to feel out as I want to develop a product and possibly bring it to market if it makes sense.

I currently have a lithium auxiliary battery mounted in the bed of my truck (which has a topper on it). I live in Colorado and winter is coming up, so its going to get cold. I'm sure everyone knows that you can't charge lithium batteries when the battery temp is 32 degrees F and below. So since I can't use engine heat to keep the battery warm and a battery doesn't generate much heat by itself to warm itself up from use (even if I have it wrapped in a thermal wrap), I'm looking to develop a thermostatically controlled DC powered battery heater.

So this leads me to my question for everyone:

I'm curious how many people use a lithium battery as their auxiliary/house battery and have it mounted somewhere that isn't temperature controlled and live in a colder climate that can get below 32 degrees F.
Also, if you were in my situation, what would you do to heat your battery up so it can charge in cold weather and maintain near its rated capacity? Or if you have any product recommendations that would work - it has to be DC powered, not AC.

Thanks,

Jimmy
 

john61ct

Adventurer
DC 12V heating pad, truckers market very cheap.

Silicon pads, similar to diesel fuel line and propane tank warmers, can include thermostat. eBay chinese sellers will quote on custom shapes.

Really hydronics would be ideal. . .

Foam slab box for insulation.
 

john61ct

Adventurer
Easiest is ensure portable modules, bring them inside your living space to stay warm.

Note even 20°C means lower charge C-rate required.
 

shade

Well-known member
Easiest is ensure portable modules, bring them inside your living space to stay warm.

Note even 20°C means lower charge C-rate required.
I noticed Victron has a low temp charge cutoff at 41*F. It can be adjusted higher, but no lower.
 

spressomon

Expedition Leader
Battle Born's LFP BMS has a low temp cut-off for charging. For those of us in a milder 4-season climate this would work fine; however if the battery, in your climate, would rarely get above 32F for week or more then that would be a limiting factor for sure.

I am using Victron's low temp sensor with their solar charge controller to stop the current from PV to the LFP in our little trailer when its in storage...
 

shade

Well-known member
Here's a thread on it.


For batteries in a vehicle it would be nice to have more than 1 (top of the battery) place to pick up the temp and an insulated box will require cooling in the summer.
I'm thinking that an insulated box could be more of a cover, like setting a box over the battery. In the summer, just remove the cover/box, and don't worry about cooling it.
 

hour

Observer
I'm thinking that an insulated box could be more of a cover, like setting a box over the battery. In the summer, just remove the cover/box, and don't worry about cooling it.

That's my plan, and why I didn't attach anything to the lid of my ammo can build. Just going to remove that in the warmer months.
 

67cj5

Man On a Mission
Why not fit a peltier cooler to it or fit it in to a pelltier cooler because some of them are reversible where they can be made to heat food up to 65*c so there is no reason why it can't be used to keep a battery warm instead of food and some of then have adjustable Cold and Hot temperature controls. Like the waeco Dometic models along with some of the cheaper made in china models.
 
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Alloy

Well-known member

It sounds like some sort of heating panel is internal that uses the charging source to keep the internals at a tempt that can keep the battery operating in cold climates.

Xantrex has a heated battery as well.

The Relion heater is 10 amps for a 100Ah battery.

It would be nice if they provided the Ah needed to keep the battery above 30F at a specific temp, say 0F... but maybe they don't want to do that. Guess one could stick it in a freezer and give it a go.
 

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