Car chargers. Basically. Don't have enough output for these. No matter what car charger I try for my Iphone 6, it just barely keeps it alive. Unless its powered off, its not charging.
I don't see any difference with these. Even using an inverter would not work, unless you have a 12v car battery and connect the inverter directly too it. Through your lighter outlet in your car won't work.
For the field. Better off buying a good high charge capacity backup battery. I have one thats 2.1 amp output and charges my iphone in a half hour. 50,000mhamp. More then enough to zap one of these in the field. It uses a usb connection, so not sure if it could work.
I don't have time to check, but if a usb charger exists for them this would work.
On a cold day my iphones glued to it so it can't fail.