18650 performance in extreme cold?

steve1541

Newly Enlightened
Joined
May 10, 2010
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I know this has been covered, but I have a specific scenario question...

I use a light for night hunting that takes an 18650. We have hunted in temps down to -8 F. It works like this: we get out of the truck, turn on the lights, set up and sit with the lights on for 30-45 minutes. Get back in the truck and go to the next spot. We are getting 1.5 hours per battery right now. Spares will be kept close to the body in an inside pocket.

So, my question is, if we are keeping the spares warm and the one in the light is turned on as soon as we go out in the cold, how much of a performance drop will we see? Does it help if the battery is generating it's own heat before having a chance to get down to outside temperature? I saw a test that froze the batteries and then ran them in inside temps. I can't find anything with warm batteries and taking em out in the cold and using them right away.

I hope my question makes sense...

Steve
 
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