Yurtdweller
Solar Enthusiast
Diy battery warmer-Seedling Warmer
I'm in East-Central Texas. I recently acquired a pre-built battery pack of 4 LiFePo4 prismatic cells @ 12v, 100ah, with a Daly 100a smart BMS. I had been considering buying a warmer, but we rarely(until this week) see sub-freezing temps where I am. If it does get below freezing, it is usually only at night. My thinking was, if it does get that low, it is not during the charging part of the day, anyway. Oh, was I wrong! So, just one day before the forecast storm, I decided I needed to get a warmer, asap. I have been dealing with a loved one's health emergency, and did not realize just how bad the storm would be until the last minute. So, one day to order and receive? I go to Amazon. This is what I settled on. The BN-Link Heat Mat & Thermostat. It is meant to be put under a tray of seedlings. It is a thin, fairly rigid plastic mat with no obvious ridges from heating elements. Just thin, tough, and flat. I opted for the 10" x 20.75" model, running at 20 watts. It is a two-piece product. The thermostat, with digital readout and temperature probe is one component. It plugs into a wall outlet(inverter). It also has an output outlet on it, with a standard grounded plug outlet. The heat mat simply plugs right into that.
The instructions indicate that the thermostat can handle loads up to 1000 watts.
Digital indicator shows actual probe temperature while operating, as well as indicating whether the unit is currently warming or idle. I have the pad under a piece of inch thick foam, and my pack sits on top of that. I have an insulating blanket over the whole thing. I live in an uninsulated yurt, and temps reached -14°c. The pack never froze up, and I was able to charge at .45C(my system's maximum capacity) in sub-freezing temperatures. I also put my drone batteries under the blanket to preserve them. I have been using this for four days now, with zero issues. I did, of course, fiddle with the temp settings a bit, to maximize power savings while keeping the pack right around 10°c(this is the temp that will restart the bms after a LTD. The thermostat-reported temperatures are right in line with the bms-reported temperatures. The thermostat and the pad come with generous cord length. I am able to keep the readout outside of the thermal blanket to read and adjust it easily. When I do the final assembly, I will tuck everything into my home-made power center, and insulate with foam board. Disclaimer: I am not affiliated with this company and will receive no consideration from them regarding this review. If permitted, and if requested, I will post a link. Btw, price: $32 USD.
I'm in East-Central Texas. I recently acquired a pre-built battery pack of 4 LiFePo4 prismatic cells @ 12v, 100ah, with a Daly 100a smart BMS. I had been considering buying a warmer, but we rarely(until this week) see sub-freezing temps where I am. If it does get below freezing, it is usually only at night. My thinking was, if it does get that low, it is not during the charging part of the day, anyway. Oh, was I wrong! So, just one day before the forecast storm, I decided I needed to get a warmer, asap. I have been dealing with a loved one's health emergency, and did not realize just how bad the storm would be until the last minute. So, one day to order and receive? I go to Amazon. This is what I settled on. The BN-Link Heat Mat & Thermostat. It is meant to be put under a tray of seedlings. It is a thin, fairly rigid plastic mat with no obvious ridges from heating elements. Just thin, tough, and flat. I opted for the 10" x 20.75" model, running at 20 watts. It is a two-piece product. The thermostat, with digital readout and temperature probe is one component. It plugs into a wall outlet(inverter). It also has an output outlet on it, with a standard grounded plug outlet. The heat mat simply plugs right into that.
The instructions indicate that the thermostat can handle loads up to 1000 watts.
Digital indicator shows actual probe temperature while operating, as well as indicating whether the unit is currently warming or idle. I have the pad under a piece of inch thick foam, and my pack sits on top of that. I have an insulating blanket over the whole thing. I live in an uninsulated yurt, and temps reached -14°c. The pack never froze up, and I was able to charge at .45C(my system's maximum capacity) in sub-freezing temperatures. I also put my drone batteries under the blanket to preserve them. I have been using this for four days now, with zero issues. I did, of course, fiddle with the temp settings a bit, to maximize power savings while keeping the pack right around 10°c(this is the temp that will restart the bms after a LTD. The thermostat-reported temperatures are right in line with the bms-reported temperatures. The thermostat and the pad come with generous cord length. I am able to keep the readout outside of the thermal blanket to read and adjust it easily. When I do the final assembly, I will tuck everything into my home-made power center, and insulate with foam board. Disclaimer: I am not affiliated with this company and will receive no consideration from them regarding this review. If permitted, and if requested, I will post a link. Btw, price: $32 USD.
. Worked! 
