I want to take my M2Z out with me when duck hunting. Issue is temps outside a at freezing and duck hunting by default is around water (ie wet) I have a waterproof case for the drone but keeping the batteries in a pocket is really not a great option. I was thinking about getting a waterproof bag and putting the batteries in it with some air activated hand warmers (Hot Hands). the warmers get warm but not hot just didn't know if external heat like that was a good idea.. Thoughts??