Reptile Heating Pad To Keep LFP Batteries Warm?

[Solarcabin Channel]

There has been a few discussions on self heating LFP or using external heaters and it occurred to me I used to have an iguana and used a small pad heater in the tank that actually got very warm and used low watts.

So I looked for them on Amazon and they have lots of models big and small and some with a thermostat and only 6-8 watts.

I am thinking one of those with a thermostat would keep an LFP warm enough to charge in an insulated box.

My batts are inside the cabin but if anyone tries one let us know if it works!

Reptile tank heating pads

Amazon.com : 12 volt reptile tank heater

 

[gotbeans]

Yea I use a 20 watt one and it has no problem heating it up in pretty much any temperature at 4inch of rockwool insulation.
I now have 8 inches of it and it's set to 75-80F now (pushing it even hotter, used to be at 50F) also have no issues..
so I assume 6-8 watts wouldn't really have any issues either, but might just be on non stop where-as mine turns off

The R value of the insulation should be around 24 (at 8 inches)

My batteries are also not "inside" (where they are is not heated, other than the battery and the heating pad).
It has gotten down to 28 degrees ambient around the batteries, they were set to 50F and they were at 50F no issues, the heater turned off and then temp dropped and it turned back on.
It is going to be 23 degrees tomorrow I have it set to 75-80 degrees so it turns on at 75 degrees and turns off at 80. I'll see what it does

My heater is something like this. I've had it probably 10+ years.. It's 12x24 inches so basically 2 of these.

https://www.amazon.com/MQ-Terrarium-Thermometer-Adjustment-Seedling/dp/B07XDHNNYS/

 

[gotbeans]

Well I decided to throw insulation around my single isolated battery for better single unit testing and only have that hooked up
It didn't get as cold as it claimed, maybe tonight it will.. it seems they claim 20 degrees but it always only gets to 28-30 degrees and when they claim 33 degrees it gets to <26 degrees lol
I'll continue to test but I think the conclusion is it works very well and you don't even need anything special for your box.. I'd use concrete board + rock wool / mineral wool just so it can't catch fire though

As you can see there are plenty of gaps and cracks in the insulation. It is 1 lifepower4 battery at 48 volts
~60 watt being drawn (including the inverter itself) because my lights are like 2-4 watts
an additional 20 watts when the heater is turned on which it isn't a lot of the time
Last night it was on/off and it got to 30 degrees in here and kept it 72 - 75.7 and kept kicking off since it was plenty warm.
It's 38F right now in here and the battery box is 78 degrees, the cells might be warmer since my temp probe is outside of the box (it's on the top.. and heat rises, so they might be colder too but I assume it dissipates in every direction idk)

anyway I think it's easy to conclude a 20 watt lizard heater with only 4 inches of insulation can heat batteries in 30 degree weather with flying colors being able to keep it ~75 degrees.
You can probably go down to the teens like this, and more insulation into the negatives. Especially if you have no air gaps in the box you make