Im new here [TANKS]

[Teresa Fortman <bratboys1-at-juno.com>]

Hi,my name is Nick
I live in Tacoma WA
Im 14 Years old and got the inspiration to build an rc tank from you guys
im working on a near 1/6 scale king tiger and im just starting to build
the track system. Im using 2 12v semi truck heater/Ac motors direct drive
to about a 3'' drive wheels.The tracks are i guess what you guys call
tyng track system but instead of treadmill belt im using old semi truck
seat belts(my parents get these old or broken semi truck parts from
work)id like to know what battery lasts the longest in terms of running
time,time before it goes bad, and charge speedyness
and what it is and where to get it 

thanks