Bafang CST 500W Really Really Hot

Motor: 36V 500W Bafang cst
Battery: 26Ah
Controller: http://www.aliexpress.com/item/36V-48V-500W-12mosfets-electric-scooter-motor-controller/1351616109.html

I did 3 km uphill to 8% and 3 times I had to stop because the engine was really hot.
Then I went in the street to see if the air will cooled the motor, and at 30 km / h, using the accelerator, after 15 km the motor was hot again.
I connected the switch 3 speed, but the motor always give 100% at the beginning and decrease only the speed.
What makes the motor so hot? Is it right that the motor is so hot?
It may be that the halls are wrong?
Thanks
Mark

Its possible you have a false positive on the halls. the way to tell is by measuring the unloaded speed of the wheel when running in the air. It should be about 1/4 faster than the bike's top speed while riding on flat ground, and only draw around 1-2 amps. If it sucks down 10+ amps, and/or tries to spin at >45mph, then it's probably a false positive on the hall combo

You have asking for help for the last 10 posts, but never really given much in the way of clear info.

Is this a hub install or a mid drive?
Is your pedal system a single speed.
Is it a 24V or 36V battery?
where do you live?
Is the motor too hot to leave your hand on?
Why did you ride up the same hill 3 times in a row?

he didn't climb the same hill 3 times, he had to stop three times during one climb.

A 30amp controller is probably too much current for this motor? I'd be very judicious with the throttle on long hills, and gear down and slow down,

I have a Bafang CST with 30 amp controller. It will never get hot at 30km/h I would say that you have a false positive on your hall/phase sequence.

Thank you guys!

@motomech

I'm an ebike enthusiastic, and I want to provide all the info that
people need to help me, but I'm not an expert so sometimes I forget to
give all the derails. Don't be mad at me!

I answer to your questions:

Is this a hub install or a mid drive?
-hub install

Is your pedal system a single speed.
-pedal system (PAS has a problem: is not smooth maybe for the wrong phase/halls)

Is it a 24V or 36V battery?
-36V battery

where do you live?
-Italy

Is the motor too hot to leave your hand on?
Absolutely yes, is to hot!

Why did you ride up the same hill 3 times in a row?
-One time for 3 km pedal assisted.


How can I find the false positive (the best way)? I need a watt-meter or amperemeter?


Thanks.
Mark

I'm not mad at you, but you should fill out your profile. That way, we would understand that there is a little language problem and take that into account.
I am not familiar with the "false positive" problem, but here is how to test the Halls;

If your multimeter had good thin tips, you should be able to slide them into the back-end of the plug while it is all assembled. Set your multimeter so it's set to measure voltage, somewhere in the 5 volt range. Stick the red one alongside the red wire, and the black one alongside the black wire. You should measure 5 volts. If not, there is something wrong. After that, stick the red probe into the green wire, black to black, and turn the wheel very slowly. About every inch or so of wheel movement the voltage should toggle between 5v and 0v. If it doesn't toggle, there is something wrong. Then put the red to blue, black to black, and move the wheel slowly to see if it toggles. Repeat for yellow.

You should always have a constant 5v coming from the controller on the red wire. You should have the Green, Yellow, and Blue wires alternate between 5v and 0v. Always sink the black probe to black when testing the halls. Keep an watch for a reversed polarity reading (-5V for example).

Does the controller get hot as well?

Thank you motomech. I appreciate your advices. Tomorrow I'll think I have the time to test wires.
I'll let you know.

You shouldn't need to test the halls. You just need to find the correct sequence. You have thee hall signal wires: blue yellow and green, plus three three thicker phase wires with the same colours. That makes 36 combinations. Do not use more than a little bit of throttle until they're correct. After each trial, write down the combination and the result, otherwise you might have to do the test again. This chart might help you do it more quickly:

http://www.lsdzs.net/Technical_detail/newsId=33.html

If your motor runs at all, then you don't need to test the halls. They are working. They must work for the motor to run.

"False Positive" is when you find a hall and phase combination that appears to work, but is actually incorrect. the timing is off and the motor will draw far too many amps, getting very hot in normal operation. The two easiest to see symptoms are Getting hot in normal operation, and excessive speed when the motor is held off the ground and run at full speed.
This may or may not be your problem, but you have one of the two symptoms confirmed, the heat. You need to check the wheel's speed to be sure.

Its easily solved by finding the right hall and phase combination, treating this combination as if it hadn't worked.

I constantly run a Bafang CST uphill, at 48V 20A in hot weather it happens to become lukewarm, that's it. I'm in Italy too, so overheating based upon country can be safely excluded!

Definitely a phase/hall combination issue. Actually I did have to swap them, but I have a Lyen controller, your is most probably different. Check the no-load amps, you must see less than 2A worst case. You my find on ES a vey detailed guide on the sequence to check the various hall/phase combinations.

Good luck!