K2, I have a 750w BBS02 and it seems to mate perfectly with Luna Cycle's 52V, 10 ah battery. It has ten (0-9) levels of assist and a throttle which over rides the PAS. The controller was set to 22 amps maximum, so by one level of calculation, it inputs about 1000 watts (22 X 52). It seems perfect for my use, but if you're considering the bigger system read what Karl has to say about it on electricfatbike.com.