self-heating batteries

Has anyone had experience with DJI's self-heating batteries? Usually I stick several disposable heat packs into the neoprene battery sack I wear around my waist beneath my winter parka. It works OK but is a little cumbersome. So if you've had experience with self-heating batteries from DJI...

Has anyone had experience with DJI's self-heating batteries? Usually I stick several disposable heat packs into the neoprene battery sack I wear around my wait beneath my parka. It works OK but is a little cumbersome. So if you've had experience with self-heating batteries from DJI, please...