I am new to the hobby and have a Losi Mini LST-2 which came with a 7.2V 1100 mAh battery. I was just trying to figure out what kind of upgraded battery i could use. If i am assuming correctly any 7.2v battery that will physically fit will work but i am not sure. Also what kind of Lipo battery could i get. Any info or even good battery recommendations for me would be appreciated.

Frank

mah rating is basically a capacity rating. Larger mah numbers are like a larger gas tank. Any 7.2 volt battery that you can fit should work. You may even be able to go higher than 7.2v but you'll have to check to see if your esc / motors can handle it.

Far as lipo concerned - same deal - any 2S (7.4v nominal) that will fit. Lipos are usually described with w x l x h measurement. You should know what size you have currently (can measure it) look for something very close to same size physically. Lipos come in various mah capacities and as capacity increase so does physical size.

It will be pretty obvious what your lipo possibilities are once you know the dimensions of the space available for the batt. Go with the highest capacity you can fit in it. The other concern is a low voltage cutoff for a lipo if the esc doesn't have one already. An lvc protests the lipo from being overdischarged and possibly damaged or ruined.