I didn't really see a good place to pose this question but here. What can be done to keep batteries, I am thinking more li-ion camcorder and digital cameras, charged during cold weather hunting. It seems like I charge my batteries and the cold overnight kills them. I have the same problem with batteries in flashlights and gps. Does this happen with trail cams that are not hooked to an external charging source? Does this sound like a good solution? Extra 12 volt battery hooked into the truck, solenoid so when I am driving it will charge both batteries. Then I can leave the li-ion batteries hooked into a charger connected to extra 12 battery overnight and still start truck to drive to hunting spot in morning since the solenoid will not allow draw from both batteries with truck off. I did buy extra batteries for the Oct. elk hunt. We will be tent camping at 8500 ft elevation where the lows overnight will get down to 20-25 degrees.