LifePO4 120v battery heater mats - work well!

[Jazzmonger]

These seem to work really well:

https://www.amazon.com/dp/B08TM6SSP7?psc=1&ref=ppx_yo2ov_dt_b_product_details

they almost cover the entire bottom of each rack mount battery. I got them and set up an automation in Home Assistant on 12/22 to keep them between 50-60F. This is timely bc it's frigging cold here. 9F last night. Im glad I checked the batt temps a week ago and got the heaters. Before that I had a small room heater (1200 watts) doing the job. Now Its 184w total consumption for 4 of those heaters which Im fine with! Small price to pay to save the most expensive part of our setups.





The smart plugs I use that gives all that energy data are amazing and come preflashed with ESPHome for Home Assistant.
$11 each and 10A capacity:

https://www.amazon.com/gp/product/B09JQ8MMNH/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

 

[EastTexCowboy]

Nice! Do you have the batteries in a rack? If so, how did you get these on without taking the batteries out or damaging the pads. It doesn't usually get that cold here but tonight is going to be an exception with 12 degrees and at least 48 hours below freezing. I have mine in the garage and am running a 1300W heater so it's toasty in there, but this sounds like a much better option.

 

[Jazzmonger]

One answer.... carefully! Yes, all 4 are in a rack. I used the flat end of 3 pry bars. I got one wedged in the back, then a second one in the front, then the third one in the back. Then I slipped the pad right in. Then carefully removed the wedges. You could probably use just one and some wood blocking.
For the bottom, I just peeled the self adhesive and pressed it on.