I don't think you're going to find many 72v cells, either high or low quality, if any.But yeah what are the highest quality 72v cells I can get my hands on?
Ah (amp hours) refers more to range or stamina. A (amps) is more of a power rating, probably what you are asking about.And what is the smallest performance size that won't be too weak, like 14ah?
V*A=W, so for your example, 5kW motor at 72V requires 69-70 amp battery & controller, but you must derate this because there are losses, and also degradations over time.
Starting to get up into big money territory.