i have a mag mod i just got and it came with 2 ultrafire 3.0 CR2s but those batteries really dont last a super long time, tho once i get the second set it will be pretty easy, nonetheless i was wondering what battery to use for "normal" voltage as in the same volts a regular 510 battery puts out which i assume is 3.7v. also a link would be great (to deal extreme) and how long it would last roughly