Insulating LiFePo batteries?

[dbsoundman]

I had a thought the other day… why not put some foam board around the sides and over the top of my two Lithium batteries? I have “poor man’s” heated batteries using some tank heater pads underneath the batteries. They seem to keep them warm enough but I wondered if I could reduce the duty cycle of the mats if I insulated the batteries.

My concerns are whether the insulation would represent a fire risk or if it would be problematic in hot weather. I would think it might keep the batteries cooler but I’m no expert.

 

[Albatross]

Use something like Rockwool instead of pink foam board and all the fire risk goes away.

 

[dbsoundman]

I have white foam board but same issue I guess. I should research the flammability of these things.

 

[Albatross]

well, foam board is generally fire-resistant, but it will actually burn, and usually release some rather toxic chemicals.

Rockwool, in contrast, doesn't burn, and is usually extremely chemically stable.

 

[nikitis]

Don't Lithium Ion Batteries work better under cold conditions? Not extreme cold but cooler conditions. At least with cell phone Lipo batteries that's the case. I've had my phone in desert heat before and battery drained so fast (And No, It wasn't additional or hidden applications draining the battery, I'm a tech guy and monitor that crap very well in fact), and I can cool my phone by putting it to an AC vent and the drain will slow to near stop.

I've also had longer battery life in cold temperatures in Idaho. Obviously if it gets too cold it has diminishing returns but until you hit that point cold is better for LiPo batteries. Heat also negatively affects LiPo batts and drains them faster when in use in heat.

That's been my technical experience anyway with that type of battery.

 

[Albatross]

Don't Lithium Ion Batteries work better under cold conditions? Not extreme cold but cooler conditions. At least with cell phone Lipo batteries that's the case. I've had my phone in desert heat before and battery drained so fast (And No, It wasn't additional or hidden applications draining the battery, I'm a tech guy and monitor that crap very well in fact), and I can cool my phone by putting it to an AC vent and the drain will slow to near stop.

I've also had longer battery life in cold temperatures in Idaho. Obviously if it gets too cold it has diminishing returns but until you hit that point cold is better for LiPo batteries. Heat also negatively affects LiPo batts and drains them faster when in use in heat.

That's been my technical experience anyway with that type of battery.

That's correct, but you also have to think about the difference between keeping massive batteries on a metal tray inside a metal box on the outside of a larger structure compared to keep a cell phone in a pocket next to a warm body. Generally keeping them above freezing to about 60 is where you'll see the best results, and then once you start to get above 72-75 is where you'll start to see some diminished capacity in performance. And that will really get noticeable once you hit over 80 and 90 degrees.

 

[Stinky-ClassB]

This touches on a question I've been scratching me poor scalp over. I want to leave my batteries in a cabin in the Bruce Peninsula. There's nothing to keep them warm and I expect the ambient to go far below freezing. There are some sla batteries there now that the previous owner left for me. They're connected to a few solar panels and encased in white foam insulation. In any case I can make out what good the insulation is doing unless the batteries are generating some heat themselves.

 

[nikitis]

Some heat will be generated if being trickle charged during that time, otherwise they shouldn't generate really any heat if not connected to anything.

I imagine the lifepo batteries as long as it's not cold enough that they don't crystalize internally should be fine.

The electrolytic lithium freezing point is -76 F. I don't think it's going to get that cold for you in storage.

 

[Albatross]

Even insulated batteries will drop to ambient on a long-enough timeline.

If you're going to store some batteries there and you worry about them freezing, then I'd probably try to figure out a way to keep them above freezing, even if it means trying some kind of a heater or something with the thermostat set to 40°-50°.

 

[Diverdude0075]

My lithium ion batteries have a built in safety that won't allow them to charge below a certain temp to protect them. I think insulating them is a great idea. I plan to fit my under the bed so they are protected from the cold.