Hi all. I have planned for a trek to Har ki doon, India, from may 9 to may 23 this year. I will be carrying a D3300 with the kit 18-55 mm lens. now I have some questions on the batteries. For the better part of the trip, that is 8 days, there will be no electricity to charge the batteries . i will carry one additional battery. Can you guys give any tips on how to handle batteries in cold? the temperature will be close to 10-15 centigrade in the day and about -5 to 5 in the nights.