I bought a 36v 500w kit on Ebay and I think my controller went bad. I am having a hard time finding another controller. So I have two questions:

Where can I find a 36v 500w controller and are they universal? I knwo the voltage is not so I can't use a 48v controller but if I find a 36v 500w controller, will the plugs be the same and will it work the same?

hi you can use any controller from ebay etc for your motor 36v 48v if you got battery of same volts. all connections are usually the same but if it does not work correctly first time then turning around the hall and phase wires will get it working. phase wires are the three thick wires blue yellow and green. hall wires ere the five wires in the smaller plug. red black blue green and yellow. connecting to your motor as is may not work right away but some wire rearranging will get it going. their are 36 combinations i think. ask if you need more help cheers.

That is great information. Thanks for responding. Now, can anyone recommend a supplier of the 36v 500w controller for a brushless motor hub. I am not too happy with the ebay seller that sold me the kit. I have sent several emails and have not had any response so I am on my own now.

You can check the for sale area at endless sphere.

https://endless-sphere.com/forums/viewforum.php?f=31

hi if you cant get any response from ebay seller i would send him an email stating that under the consumer act the item is not fit for purpose and that if he does not get in touch you will do a charge back on him and get all your money back that should make him twinge a little. any brushless controller that is 36v will work if you do buy go for more watts and get a bit more pull from your bike say 36v 750 or 800 watt . ecrazyman on ebay is trustable.

See, this answer is wrong -- voltage is not the only thing to keep in mind. Amperage is important as well, but more fundamentally I'm thinking of sensored vs. sensorless.

There's two classes of brushless motors -- sensored and sensorless. You've just described a sensored setup.

The three wires are for the motor itself, and the five wires are for the sensors. If your motor has three wires, it's sensorless, if it has eight (three fat, five thinner), it's sensored.

Brushless ESCs (electronic speed controllers) come in two main flavors -- sensored and sensorless. Again, they either have three fat wires coming out (sensorless), or three fat wires + five thinner wires (sensored).

Modern stuff is generally (but not always) sensorless, as it has several advantages -- fewer wires, the timing of the motor is controlled by the ESC itself rather than having to adjust the sensors in the motor, the motor can be reversed by swapping any two wires (it really is that easy), etc.

The only advantage that sensored has is that the ESCs required less "smarts", but considering how much you can cram into a $1 chip, that really doesn't matter any more.

One more thing to mention -- a sensorless ESC can be used with a sensored motor. Just don't hook up the five sensor wires, only hook up the three motor wires. There's no downside to this setup besides some extra wires you might want to cut off or push out of the way. The opposite does not work, however -- sensored ESCs require sensored motors.

This is all really good information and very much appreciated.

So if I understand what everyone is saying here is what I have and what I can do:

1. I have a sensored motor hub because I have three larger wires and also the five smaller wires.

2. I can use a sensorless controller with my sensored motor? Doesn't the hub need the controller to send the signals to adjust the sensors? I don't quite understand this one.

3. I should get a controller that is 36v but is higher in wattage such as a 36v, 800w controller. What will getting a controller with more wattage get me, more speed or just more reliability?

It is all starting to make sense to me now and I can't tell you how much I appreciate this information.

Yes.
Yes, you can use a sensorless controller. The ESC can detect the orientation of the motor by looking at the voltages going back and forth on the three wires and doesn't need the five wires.
A larger capacity ESC will not get you more speed -- but it will get you more wiggle room before something goes wrong and causes the ESC to shut off or burn up if you try to overload it.

The sensors tell the controller how fast the motors turning so it can commutate correctly (adjust the electrical signals to the motor for speed). Some like the higher voltage controller so you can add batteries / voltage to get for speed.