I use the common sense 1500 2s, thunder power 1320 and the Apogee 1300? i think it is and they all fit no problem.
Then for fun I fit a common sense 3s 1600 i think it is in my 18R and then I converted it to a 18B and the battery fits, pushes the body up slightly, but its still protected.
Im running a Quark 33A, C4 9200kv, 3s 1600, street rage tires and about 28g of lead weight in the front to keep it from flipping.
And I must say its a good basher.