A while ago I posted about my DIY Lithium Battery Heating system. So far, with temperatures at night reaching into the 20s (F), it has been working great. The batteries in the trailer have BMS with Bluetooth and it records the batteries average internal temperature. Staying around 40 degrees day and night. I wanted to know how often during the night the heating pad turned on. I installed a small LED on the outside of the trailer that illuminates when the heater is on. My "RING" camera security system records through the day and night and I can go back and review the video with a time stamp. I can see the light turning on and off. Last night it got down to 20F. The battery heater turned on for 7 minutes every hour +/-.....200ah batteries this morning are at 93%.....I'm very pleased with this performance...
http://rvbprecision.com/rv-projects/lithium-battery-heating-project.html
RoyB
Dartmouth, MA
2021 RAM 2500 4X4 6.4L
2011 Forest River Grey Wolf Cherokee 19RR
520 w solar-200ah Renogy Li-Epever MPPT