BATTERY HEATING?

[Pete-y2k]

What's cold weather battery heating all about? I was under the impression that recharging and storage within certain temps was the only concern. Does motive use fall within a temperature constraint? When riding at 45°f, should my battery be kept at a higher temperature?

 

[indianajo]

Cold temperatures increase the resistance of a LIIon cell. Thus the range and max amp draw are decreased. I found 45 dg F about doubled my battery draw. A 24 mile round trip took about 60% of a 17 AH battery.
In my garage, I have a back heating pad that I wrap over the battery on cold winter nights and run on low. LiIon doesn't have the absolute protection against freezing that lead-acid batteries do.

 

[harryS]

It seems counterproductive to me to use the battery to heat itself on a cold day. We're losing enough power anyway because of the temperature.

Yesterday at 48F, I burned 3AH to cover 12 miles. Normally use 2AH. If I had been using a 100W heater, that would have been 100 watts-hour in an hour, which would have been another 2AH.

The chemistry will self heat the battery a bit while riding. I hear many cold weather riders put an insulator around their batteries so any heat self generated doesn't leave.

 

[AHicks]

I've noticed a loss on my last couple of rides as well, both done in the 40's.

Brrrrr! Time to migrate south for the winter...

 

[Dave711]

Cold temperatures increase the resistance of a LIIon cell. Thus the range and max amp draw are decreased. I found 45 dg F about doubled my battery draw. A 24 mile round trip took about 60% of a 17 AH battery.
In my garage, I have a back heating pad that I wrap over the battery on cold winter nights and run on low. LiIon doesn't have the absolute protection against freezing that lead-acid batteries do.

Interesting! Good info to know. Way back when (ok, in the 1950s), my father used to take the battery out of his car on very cold days and put it on one of the heating vents in the house overnight so that it would start his car in the morning. I guess this works as well for LI ion cells.