Lithium battery and cold weather experience

WayneW

I just wanted to share my recent experience with a lithium battery in cold weather.  We have a 100 aH AmpereTime (now LiTime) LiFePO4 battery mounted in the front box of our 320 Boondock.  It does not have cold temp cutoff and it's not self-heating.  It's inside an insulated box that I built.  I have a Victron BatterySense that is networked with the Victron mppt solar controller and it set to disable charging when the temp is below 1deg C.

We were recently camping at about 7000 ft.  Temps at night were in the low 30s but one night it dropped to 20 deg F.  I checked the BatterySense and the lowest the battery temperature ever got was 3 deg C.  The combination of the heat generated within the battery, along with the insulated box, must have kept the temp that high. 

I was initially a bit concerned about the issue of charging below freezing, but this recent experience makes me much more comfortable.  I don't see us camping too much when nighttime temps are lower than 20 deg F, and even if we do, the battery appears to be staying warm.  I'm comfortable with our choice of a lower cost battery without the cold temp charging cutoff or the self-heating feature.  Everyone will make their own choice, but I just wanted to share my experience.

Grumpy_G

While the battery doesn't have low temperature charging protection the Victron MPPT charge controller provides the function in your configuration. Basically the same thing just implemented differently. One caveat is that it doesn't protect the battery when the trailer is connected to shore power or the tow vehicle. 

SLJ

My batteries have low temp cut off but I also installed a Victron Smart Battery Sense ($39) that tells my Victron Smart Charger and my Victron solar controller to stop charging if the battery compartment drops below freezing. Probably never need it but it's a backup. If I'm on shore power I shut the batteries off anyway.

Hammick

Anybody camping in cold weather with the battery outside might want to add one of these to their backup supplies.  They also sell them with a digital thermostat.  I have a large one under a 48v 280ah pack at our offgrid place.  I use the largest aluminum baking sheet you can buy on top of the pad then the batteries go on the baking sheet.  That distributes the heat.  The battery box is insulated with 4" foam and in the summer, early fall and late spring I remove the 4" lid.  The seed heating pad rarely needs to run as we leave our inverter hot to run the fridge, cameras, internet, routers, etc. (discharge and charging heats the batteries enough)  I set the pad to 50 degrees.  Very cheap insurance to protect expensive batteries.  Place is at 5,200' in Montana and the garage is insulated but I have seen it drop to mid-twenties in the garage on a few occasions during prolonged sub 0 degree weather.

If I was the OP I would get this one without the thermostat and just plug it in when the temps are expected to plummet.  I wouldn't worry about needing an aluminum plate.  If the pad is smaller than the batteries you could just use aluminum foil or HVAC duct plates.

https://www.amazon.com/VIVOSUN-Waterproof-Seedling-Hydroponic-Standard/dp/B00P7U259C/ref=sr_1_1_sspa?crid=39F7IC8EYX4Q8&keywords=seed+heater&qid=1708281468&sprefix=seed+heater%2Caps%2C142&sr=8-1-spons&sp_csd=d2lkZ2V0TmFtZT1zcF9hdGY&psc=1