On Tuesday, March 20, 2018 at 9:51:23 PM UTC-7, 2G wrote:
On Sunday, March 18, 2018 at 8:29:30 AM UTC-7, Dan Marotta wrote:
Well, what immediately comes to mind is the confusion between LiFePO4 and Lithium Ion. Those are different chemistries. 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. After a year of removing the batteries and taking them home to charge, I had the confidence to leave them installed in the glider, in the hangar, with the chargers connected and plugged in. Again, no problems with LiFePO4. YMMV.

Dan

On Sunday, March 18, 2018 at 8:38:12 AM UTC-6, son_of_flubber wrote:
When researching a step up to LiFePO4, I stumbled across this tidbit at http://batteryuniversity.com/learn/a...w_temperatures

"Many battery users are unaware that consumer-grade lithium-ion batteries cannot be charged below 0°C (32°F). Although the pack appears to be charging normally, plating of metallic lithium can occur on the anode during a sub-freezing charge. This is permanent and cannot be removed with cycling. Batteries with lithium plating are more vulnerable to failure if exposed to vibration or other stressful conditions. Advanced chargers (Cadex) prevent charging Li-ion below freezing."

Advancements are being made to charge Li-ion below freezing temperatures. Charging is indeed possible with most lithium-ion cells but only at very low currents. According to research papers, the allowable charge rate at –30°C (–22°F) is 0.02C. At this low current, the charge time would stretch to over 50 hours, a time that is deemed impractical. There are, however, specialty Li-ions that can charge down to –10°C (14°F) at a reduced rate."

The also applies to lithium battery in your phone/computer. If you should happen to leave it in a cold place, you might want to warm it up before charging.

There's no confusion between LiFePO4 and Lithium Ion because LiFePO4 IS a Lithium Ion battery. Lithium Ion is a generic term that includes all lithium chemistries.
http://batteryuniversity.com/learn/a...of_lithium_ion

There should not be, but unfortunately there is confusion, because of the loose use of the terminology. If it has lithium in it, it is a Lithium Ion battery, but beyond that there are big differences in chemistry and mechanical construction. The concern about sub zero charging has to do with plating on the anode, however each of these different battery chemistries use a different anode material. One might assume that with different anode material they would be more, or less, susceptible to the plating problem. I cannot find any scholarly paper that discusses LiFePo4 in particular, with respect to charging temps.