which electronic component is defective?

Left my 72V brushless motor bike sitting for 1.5 years rusting away in the carport. Its been ultra reliable in the time ive used it. Battery full. Greentime controller. When I first tried it it doesnt work of course, rust everywhere. So I checked and redid all the wiring, but forgot my initial phase combination.

Tried all 6 phase combinations. Theres one where it spins backward at a slow speed, and one forward at the right speed. The latter is presumably the right one. The controller has no self learning ability.

However, the motor just squeals when you start applying moderate loads to it (pressing the brake or putting the front wheel to a brick wall). In the good old days it will easily spin the back wheel under its own weight if it cant move forward (im not sitting on the bike of course).

Whats the problem?

Bad hall sensor, or bad controller? I'm using a 72V A123 battery pack and its BMS doesnt look like a cheap one.


thanks to whoever can help.

You still don't have the right combo. You have a false forward setting. Depending on your point of view, there are 9 combinations, or 36 combinations. Happy hunting.

It could easily be a bad hall sensor, or just some crap on the contacts that is preventing you from finding the right combo.

This should help.
http://endless-sphere.com/forums/viewtopic.php?f=2&t=68722&p=1036552&hilit=phase+chart#p1036552

IronMonkey,

Don't listen to them. If you didn't change the hall combo, then of course you have the right phase combination by trying the 6 possible. Motor squealing is not a symptom of incorrect wiring combo.

You didn't mention the motor type. It sounds like it's a geared hubbie and the clutch is slipping. FWIW, putting your front wheel against a wall and turning the throttle is not something you ever want to do.

More info needed.

Tried all 36 combinations, no luck.
Im happy with it in one of the numerous combinations where it goes forward at a slower speed(i suspect this is the controller going on sensorless mode), I dont need it to go at 70km/h anymore.


But...there looks like theres a dead cell in the A123 battery pack, no wonder the BMS was cutting out regularly. What a sad ending to my electric bike hobby. Will try reviving the cell, but otherwise cant spend anymore time on this.

P.S The motor is one of those generic China 48V 1000W brushless non-geared motors. It has served me well running at 72V.