800w hub w/ 350W controller

[imginit]

I burned out my Q100CST 36V 328rpm motors on steep hills (201rpm top speed is too slow).

Hoping the Q128CST 328rpm 36V has more heatsink ability to handle the low RPM. What will happen when I use it with the existing controller? I cannot change the controller bc of space constraints. I believe the controller is rated for 15A max. What will happen when I set it up? Will it just limit current to 15A, giving ~540W?

S06S/CON63 36V controller: https://bmsbattery.com/home/1006-s06s-250watts-torque-simulation-sine-wave-controller.html

Q128: https://bmsbattery.com/motor/768-18602-q128c-135mm-500w-rear-driving-ebike-hub-motor-ebike-kit.html#/214-rpm-328/497-voltage-36v

Q100 https://bmsbattery.com/motor/651-16347-q100c-cst-36v350w-32-hole-rear-driving-hub-motor-ebike-kit.html#/214-rpm-328

 

[SlowCo]

Should work fine but you'll leave a lot of performance on the table.
Maybe overvolt the motor with a 48V/52V battery and controller later?

This 6FET 20A controller is the same size and can handle a 48V battery:
https://bmsbattery.com/home/1133-18...e-controller-36v.html#/319-display-no_display

 

[motomech]

I burned out my Q100CST 36V 328rpm motors on steep hills (201rpm top speed is too slow).

Hoping the Q128CST 328rpm 36V has more heatsink ability to handle the low RPM. What will happen when I use it with the existing controller? I cannot change the controller bc of space constraints. I believe the controller is rated for 15A max. What will happen when I set it up? Will it just limit current to 15A, giving ~540W?

S06S/CON63 36V controller: https://bmsbattery.com/home/1006-s06s-250watts-torque-simulation-sine-wave-controller.html

Q128: https://bmsbattery.com/motor/768-18602-q128c-135mm-500w-rear-driving-ebike-hub-motor-ebike-kit.html#/214-rpm-328/497-voltage-36v

Q100 https://bmsbattery.com/motor/651-16347-q100c-cst-36v350w-32-hole-rear-driving-hub-motor-ebike-kit.html#/214-rpm-328

Q100 "328" motors, especially the CST only work in wheels 20 inches and smaller. They are geared so high they can never get up into the proper RPM range. As you found out, "lugging" the motor at a speed 1/2 or less than the top speed kills them.
Using the Q128 328 will be a little better, but if you use that puny 15 A controller, you will likely have the same problem. That's be you actually want more Amps (Watts) when climbing a hill to keep your speed up. Electrical motors are not like gas motors, it's not a case of; "Well, if I use less throttle there will be less heat and....." You want to hit the bottom of the hill as fast as possible to keep the momentum up and if you find the bike slowing to less than half the top speed, it's time to jump off and push.
What you really want to use is a mid-speed (260) motor and use the Voltage to get you to the speed you want. There are not many choices for a mid-speed w/ the Q100 and that and other reasons I use a larger Bafang these days. I think a mid-speed is available w/ the Q128. That ancient controller from BMS Battery is junk. If you don't have any space for anything larger, get an Infineon from Grin or Lynn. It will cost more and you won't have the features of a new Chinese sine-wave, but you can get the 20 to 25 Amps that you need in a controller the size of a pack of cigs.

 

[motomech]

I've made at least 1000 posts about mini-motors , the q100's, how to use them, speed ranges and controllers over the years. But since nobody is interested in small hub motors anymore, it's not worth me going into detail here.
But you can search my posts using those search-words above.

 

[E-HP]

I burned out my Q100CST 36V 328rpm motors on steep hills (201rpm top speed is too slow).

Hoping the Q128CST 328rpm 36V has more heatsink ability to handle the low RPM. What will happen when I use it with the existing controller? I cannot change the controller bc of space constraints. I believe the controller is rated for 15A max. What will happen when I set it up? Will it just limit current to 15A, giving ~540W?

S06S/CON63 36V controller: https://bmsbattery.com/home/1006-s06s-250watts-torque-simulation-sine-wave-controller.html

Q128: https://bmsbattery.com/motor/768-18602-q128c-135mm-500w-rear-driving-ebike-hub-motor-ebike-kit.html#/214-rpm-328/497-voltage-36v

Q100 https://bmsbattery.com/motor/651-16347-q100c-cst-36v350w-32-hole-rear-driving-hub-motor-ebike-kit.html#/214-rpm-328

Are you pedaling?

Basically the bigger motor buys you more time before meltdown. The smaller motor was the weakest link for what you were making the bike do. But additional time may shift the problem, making the controller the weakest link, so that gets fried before the motor. Pedaling harder also buys more time, and might be the best solution.

 

[Sandguppy]

But since nobody is interested in small hub motors anymore.

I've learned a lot from your posts, thanks.

Picked up a bafang fm-g320250r for a mid mount sand bike. I'll be starting a build thread soon.

 

[Chalo]

I burned out my Q100CST 36V 328rpm motors on steep hills (201rpm top speed is too slow).

You might feel like it's too slow, but your motor is telling you it doesn't have the power to go as fast as you want, so it stalls in a low efficiency range and overheats. If you are only going to use a 350W controller, use the low RPM motor. If you want to go faster, use a higher power motor and controller.