We have a 500w bike that's been running on a KT-17a for quite a while now (2 years). This was done just before they introduced the 9 mosfet version rated at 22 or 25a. Will the 17a handle the abuse a 22a will, heck no! Is it sufficient for a 500w bike that not going to be pushed hard, I think the answer there needs to be answered by the rider.
Hard not to agree with
@harryS here, it's spelled out clearly in the laws of electricity, and it's confirmed by my own experience:
"This formula is true, watts = amps x voltage. You want 750 watts. then the amps and voltage product must equal 750. So 17A means 17 amps, and assume a nominal voltage of 50V, that means a theoretical peak of 850W, In the real world, you might get 700 briefly on a KT 17A system.
I don't remember what this 17a controller peaked at before cutting it back to get PAS 1 power where we wanted/needed it, but I can tell you that the 22a will pull 980 watts pretty easily for short bursts (like crossing a busy road for instance) - and again, that's AFTER being cut back to get PAS 1 power where we want it. YES, both the 17a and the 22a had to be dialed back to get PAS 1 power to the level we wanted (easily done in the display parameters)- assuring good low speed control at speeds well under 10mph.
Just to be absolutely clear, when you start pushing the controller's limits, or those of your motor, it has to be done keeping in mind BOTH are going to heat up quickly if abused/used for more than a few seconds. That said, a 500w motor does get pretty sporty when fed power exceeding it's capacity..... that will put a smile on your face pretty sure!
I think you'll be fine with the 17a keeping that in mind..... -Al
