Thread: The inadvisability of charging LiFePO4 batteries below 32F/0C (akabelow freezing)
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Old March 18th 18, 11:55 PM posted to rec.aviation.soaring
jfitch
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Default The inadvisability of charging LiFePO4 batteries below 32F/0C(aka below freezing)
On Sunday, March 18, 2018 at 2:12:31 PM UTC-7, Dan Marotta wrote:
My batteries had built-in battery management systems (BMS) which monitor
charge level, temperature (I think), and cell balance. Maybe that was
the difference.Â* BTW, this is the battery I used:
http://www.tenergy.com/31383. I bought the specified charger at the same
time and, during the first year, I would check regularly by touching
both the battery and the charger and never felt a noticeable temperature
rise.Â* The battery was also a drop-in replacement for the standard AGM
batteries used commonly in gliders.Â* It was considerably lighter.

On 3/18/2018 11:02 AM, son_of_flubber wrote:
On Sunday, March 18, 2018 at 11:29:30 AM UTC-4, Dan Marotta wrote:
I used LiFePO4 and charged them over the winter months in NM (lots of zub-freezing nights) using the chargers supplied with the batteries without any problems.
Thanks for reporting your first hand experience. Maybe your charger has a temperature sensor that stops charging below 32F.

I first came across the warning in the user manual for a combination
battery_charger+battery_isolator (www.westmountainradio.com 'Epic PWRgate') This device is programmable for LiFePO4 or AGM. The device uses a temperature probe to adjust charge rate. The device does not work with other Lithium based battery chemistry.

"West Mountain Radio Operating Manual Page 10
Optional Temperature Probe
The temperature probe provides valuable data for the Epic for charging.. If the temperature of the battery is too high or low on a LiFePO4 battery, the Epic will cease charging the battery. For Lead-Acid batteries, the Epic will adjust the charge voltage dependent on the battery temperature.. This allows for the most optimum battery charging.
If a probe is not used, be sure to never charge a LiFePO4 below freezing temperatures for safety reasons.
http://www.westmountainradio.com/pdf...ate-manual.pdf

--
Dan, 5J

I've seen a lot of information on the web about plating of the anode in LiPo batteries, but none on LiFePo4 which use a different alloy on the anode. On the other hand, every LiFePo4 battery I have has a charge spec of 0 deg C. Does anyone have a link to an authoritative source on this?