I am currently using an eleaf 100W mod and have a couple other mods. I want to know what the best 18650 batteries is. Right now I have a pair of Samsung 25r that have been using on my eleaf. I have this crappy Ultrafire, which I was sold with a smowell 50 watt that i have given up on. In any case. I am just curious what battery would be best for longevity. Any suggestions would be greatly appreciated.