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Minus 40F Will my LiFePO4 batteries survive?

Updated: Dec 27, 2022

Minus 40F! Will my LiFePO4 batteries survive?

12-26-22 lks

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.

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