The inadvisability of charging LiFePO4 batteries below 32F/0C (akabelow freezing)

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

Just to clarify. I'm NOT planning to use the West Mountain Radio Epic PWRgate to charge batteries for a glider.

(I'm looking into using the Epic for a 'house battery' in a camper van.)

I have two 12v 9AH Stark LiFePo batteries. On their website it gives –20°C to 60°C (–4°F to 140°F) as operating limits and a charge temperature range of 0°C to 45°C (32°F to 113°F).

The capacity graphs for 25, 0, -20, -40 C ( https://starkpower.com/product/12-volt-9ah-battery ) tab at the bottom shows they're good batteries down to 0 C, but perhaps a poor choice for the real cold.

This explains the voltage drop in the Lake Placid wave... I will have to put a voltmeter readout in for the next camp. I remove the batteries for charging.

On Sunday, March 18, 2018 at 1:23:04 PM UTC-4, Dan Daly wrote:

The capacity graphs for 25, 0, -20, -40 C ( https://starkpower.com/product/12-volt-9ah-battery ) tab at the bottom shows they're good batteries down to 0 C, but perhaps a poor choice for the real cold.

They don't specify the discharge rate, and it's probably much higher than typical glider use. I've taken LFP batteries to 31,000', they worked fine.

Evan Ludeman / T8

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

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?

My A123 LiFePO4 battery charging document says that operating range is -50C
to +60C. Nowhere does it say that you cannot or should not charge below
0C.

Jim

I contacted Bienno for their Lithium Iron Phosphate (LiFePO4) Battery Model BLF-1209WS and they said the following;

The operating temperature is from -20 deg C to 60 deg C (14 deg F to 140 F). Then charge between 0 deg C to 40 deg C (32 F to 104 F)

On Monday, March 19, 2018 at 1:20:31 PM UTC-4, OHM Ω http://aviation.derosaweb.net wrote:
I contacted Bienno for their Lithium Iron Phosphate (LiFePO4) Battery Model BLF-1209WS and they said the following;

The operating temperature is from -20 deg C to 60 deg C (14 deg F to 140 F). Then charge between 0 deg C to 40 deg C (32 F to 104 F)

I left a message for Stark, and will forward the response here.

On Monday, March 19, 2018 at 1:37:16 PM UTC-4, Dan Daly wrote:
On Monday, March 19, 2018 at 1:20:31 PM UTC-4, OHM Ω http://aviation.derosaweb.net wrote:
I contacted Bienno for their Lithium Iron Phosphate (LiFePO4) Battery Model BLF-1209WS and they said the following;

The operating temperature is from -20 deg C to 60 deg C (14 deg F to 140 F). Then charge between 0 deg C to 40 deg C (32 F to 104 F)

I left a message for Stark, and will forward the response here.

"Hi Dan,

Both of the charts on the 12V9Ah battery page are based on 1C discharge rates.

With regards to charging below 0C, because the 12V9Ah battery is fairly small, it is always best to charge when it is above 0C. If you have been using the battery and it is just below 0C, your battery will still be above freezing internally and you will be able to charge with you 4A charger without damaging your battery.

Thank you,
StarkPower Customer Care"