Using a 750 Watt brushless controller with a 500 Watt brushless motor should not present any major problems. If the motor is used hard it may run a little hotter than it would with a 500 Watt controller, but as long as the motor does not run too hot then it will be fine. If it does start to run too hot then simply lower the amount of throttle that you give it when going uphill.
I tried to get a local e-bike store to repair my assembly. Both only repair their own ebikes and only under warranty. So I installed an Amazon 36V 500W 26 inch rear wheel kit instead ($260), where connectors fit. For existing battery and brakes, I used my soldering iron plus isolation tape instead of official connectors. My updated ebike works better than it did under its previous ebike kit. It still doesn't have an on/off switch. Increasing its top motor speed from 15 to 23 miles/hour is not legal. But I hope the police remains quite as long as I bring my driver license plus remain within 5 miles/hour within the 20 miles/hour Utah ebike speed limit.
Reinhard Dunkel, Ph.D.
I try to install the 36V 750W ElectricScooterParts.com controller (Order# 80888). Its Wiring Directions state the Thin Purple cable sets Power On/Off. My Chinese upgrade kit worked for 4 years until its controller broke. My Power cable has the same plug and connects fine, but it does not have a Power On/Off cable connected. Does that mean its power remains on? (The Chinese upgrade kit did not come with a switch, so I deattach its power cable to switch it off.)
My ebike has two brakes. I used its connected black and connected red cables to switch off its motor when using a brake with the old controller. Do I connect them now to "Brake (low)" or "Brake (high)"? What does low and high mean for the wiring directions anyhow?
My throttle has a thick black cable with a white connector at the end with blue, white, and red cables plus two black connectors one with yellow and brown and the other with violett cable. I never got its green (full), yellow (half), red (empty) LED to come on or its red button motor on/off switch to work. There are two white three cable connectors. Is the black, green, red cable one for the throttle? (Or the blue, black, orange one?) Too bad both cable and connector have male plugs, so I need to switch one to the female plug of the old controller...
How could I use the "Three Speed" Wiring Direction? Can it increase/decrease the ebike motor speed with it? Do you sell a switch which I could attach to the handle-bar? Do you also sell the white tree cable connector which I need for the throttle control?
The Chinese ebike kit never specified name or specification if its motor. It is large in the back wheel center of the ebike and it is likely 500W. Do I need to be afraid that tthe 750W controller burns the motor after a while?