On 05/17/2018 06:29 AM, wrote:
I want to concur with Dan.
I fly out of Minden and we cruise between 15,000 and 17,999. It is COLD at that altitude.
My lead batteries would lose voltage as the temp dropped. After three hours at altitude they were lucky to put out 11 volts. Of course, when the batteries warmed up alter landing they had full voltage.
The LiFePO4 batteries do not seem to affected by cold soak. They work the whole flight at full voltage.


Hmm. Flying (legally) up to 18K at other locations, I've never seen
SLA's drop voltage and then recover when they warmed up. With an
adequate battery, they don't drop below 12 even when transmitting on the
radio.

LiFePO4 batteries aren't exactly immune from the cold, both the Antares
and the Perlan 2 gliders have battery heaters that are used to preheat
on the ground, and then again in the air as needed. Using battery power
to heat in the air is better than just letting them get cold. If
;you've got enough extra capacity to get through long flights, that's
great, but so do I with SLA's.