It's a compromise between what area you have to put them, how fat your wallet was and how quick you wish to accelerate. The max amps the motor requires matched to a C rating of the batteries is the one for battery cycle life. Even though TS and CALB quote 3C discharge capacity don’t confuse that with the 3,000 to 5,000 cycle rating, that's measured at 0.3C. No one has published the numbers for 3C cycle life but don’t expect to see triple figures. If you don't have the area for big capacity but need big amps then you are going to need Headway or A123 cells that are much dearer for equivalent capacity. So, a combination of peak amp draw and capacity will give the ideal pack, area to fit it and $$ to pay for it will start the compromise section.
T1 Terry
T1 Terry