Keeping Batteries Warm for a Few Days

[New Visions Aerial]

Hello,
I'm going on a road trip and would like to take the Mavic. I plan on sleeping in my car and am expecting temperatures to be anywhere from 20F to 50F. I suppose I could put them in my pocket while I sleep, however, that doesn't sound all that comfortable. How would I keep the batteries warm for a few days?
Thanks

 

[ATLDroner]

If you are sleeping in a sleeping bag, you can put them in the bottom near your feet while you sleep. This is how i dry my clothes out when I go backpacking.

Alternatively, wrapping them in a down jacket or blanket will do a good job in insulating them from the temp.

 

[OzoneVibe]

It's less essential to keep them warm ALL the time than it is to have them at a good temperature before flying.

In the car, with the heater on, they should be warm enough within an hour, and even less if placed next to a heater vent.
Otherwise, once you're awake, in a warm pocket should also see them warm enough within an hour or so.

The other thought I'd had, but never tried, is a small one of those electric picnic food cooler/warmer boxes. Most seem to be too hot to leave them in there all the time (if switched on) but would probably warm them well/safely if left in one for a sensible amount of time?

 

[New Visions Aerial]

It's less essential to keep them warm ALL the time than it is to have them at a good temperature before flying.

In the car, with the heater on, they should be warm enough within an hour, and even less if placed next to a heater vent.
Otherwise, once you're awake, in a warm pocket should also see them warm enough within an hour or so.

The other thought I'd had, but never tried, is a small one of those electric picnic food cooler/warmer boxes. Most seem to be too hot to leave them in there all the time (if switched on) but would probably warm them well/safely if left in one for a sensible amount of time?

I had a similar thought for a small cooler. Just put some hand warmers in with the batteries and zip it up.