[RE-wrenches] LFP Battery Box Heating

[Luke Christy]

Hi Amanda,

Lots of good ideas from the list. 

I have  successfully employed an LFP strategy that used seedling mat heaters and electronic temperature controllers. I found that 60-80W of heating with a temp controller would easily keep most smallish battery banks above 50º in unheated battery areas here in Colorado- and it gets cold here too. Like others, I was worried about the reliability of inexpensive heater mats purchased on Amazon, so I started using wifi temperature controllers that could connect to a customer wifi network and push temperature data and alerts to my phone. With many heated lithium systems in the field for years now, I have yet to have a heating system failure, and I’m surprised at how little energy it seems to take to keep batteries at a safe temperature over the winter. 
There are viable site-engineered options for the situation you describe.

Having said all that, I have stopped building battery heater systems due to the appearance on the market of many LFP batteries with pre-engineered cell heating systems. If you have the option to purchase batteries with integral heaters, I’d recommend that as a first choice. 


Luke Christy
Renewable energy consultant

NABCEP Certified PV Installation Professional™: 

Solar Gain Services, LLC
PO Box 531
Monte Vista, CO 81144
719.588.3044
sgsrenewables at gmail.com

> On Nov 25, 2025, at 12:58 PM, Amanda Potter via RE-wrenches <re-wrenches at lists.re-wrenches.org> wrote:
> 
> Hello all,
> I’ve been reading past posts regarding Battery Box Heating & am trying to find a simple way to heat an OSB insulated box for various LFP type batteries.
> 
> One Battery Company’s tech support said he uses (at his own home) a 110vac incandescent bulb plugged in to a thermostat (inexpensive) that lets him heat between 32 & 50 degrees F.
> 
> I had somebody suggest the same thing with some Christmas lights.
> The box & inverter & C.C. are in an un- heated garage on the Canadian border of NY. ( It can, & does get pretty cold up here.)
> 
> Any suggestions?
> 
> It’s Off-Grid & the owners want their Starlink & Security Cameras to be on year round.
> 
> Thanks ahead of time!
> And, Happy Turkey Day!
> 
> Amanda Potter
> Energy Storage Systems
> NABCEP PVIP 
> Adirondack Battery & Solar, LLC
> (315) 212-2114
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