Power to charge them. Those rechargers are slaved into m1097s (vehicles), generators, and the like. That's a logistical non-starter, even assuming an acceptable consumption rate if you're out for ~24 hr missions, or 24 hrs as a planning factor.

but really quantify the consumption rate, ~10xAAAs burned over 2 hours of consistent use is dead accurate, and thats 1x piece of equip. So rechargeable or not, the in-mission load is the problem