Updated: Dec 27, 2022
Minus 40F! Will my LiFePO4 batteries survive?
The recent super cold wave that crossed the USA worried several of our customers that own LiFePO4 batteries. One of our customers in Wyoming reported -40F!
There are three temperatures that we consider when utilizing LiFePO4 batteries:
1) 32F. LiFePO4 batteries don’t like to charge below 32F. Actually, most batteries have a BMS (Battery-Management-System) that prevents them from charging below 32F. The number varies from 25-32F, so we just use 32F as a generic temperature.
2) -4F. LiFePO4 batteries will give you most of their charge down to -4F, making them a great cold weather battery. Their BMS will shut them off at -5F.
3) -10F. Many LiFePO4 batteries will begin to degrade below -10F. So keeping them above -10F (even better, above 0F) is a good thing.
We have a 70W 12V heater lithium battery heater that works very well to keep a battery warm. In an insulated battery box, such as an Igloo cooler, our heater will give a 40F temperature rise with only 16AH per day out of a 12V battery. If we use our custom industrial thermostat, the heater will keep the batteries between 35-45F so that they can continue to be charged.
We have tested our battery heater by placing the battery in an Igloo cooler and putting the whole thing in a deep freeze. With our custom industrial thermostat, the battery stays between 35-45F while using 16AH per day.
At Leisure Solar, we design, build and test many custom energy products for RVs, cabins, back-up power and portable power. Contact us if we can design and build something for you.