Reliance RS50 21700 5000mAh 70A Tabless Battery

These are the best high current batteries I have tried. They handle a load and last much longer than the top name brand. As far as the life span, that's something only time can determine.

Fully charged a battery one day. Let it sit out of the charger, the next day it was at 90% when I put it in my mod. Still get a full days use from one battery. No complaints.

Tons of power without the sag, also great in colder climate