Motor grinding and not spinning

[atipene]

I put my first ebike together last night, but something has gone wrong and the hub motor is making a grinding noise and turning at 1rpm for a 5 secs then stopping.

Before this, everything was going well. I had some gel cell batteries ( 4 x 12v ) that powered everything fine and I was able to test ride the bike around the block.

I recently set up a 12S1P LiPo pack and when I connected it everything worked fine again, but when I went to take the bike for a ride, the hub jerked a couple of times then stopped (no spraks, burning or heat noted anywhere). The wheel is now barely turning and making a grinding noise. If I connect the old gel cell batteries up, I get the same problem.

I am at a loss as I’m very new to these motors and controllers and don’t know where to start diagnosing.

Is it possible that the LiPo pack has shorted a hall connector and should I pull apart the hub to check the hall sensors as well? (I have little idea what this actually means)

Is there a way to diagnose the problem to the hub or controller?

Any help is most appreciated.


- 48v MOSFET controller
- 48v 500W Bafang geared brushless hub motor
- 2 x 6S 8000mAh LiPo in series

 

[shorza]

Sounds like a bad hall/phase combination.

Not all controller phase/hall colours match up with the motor's phase/hall colours.
Check:
http://endless-sphere.com/forums/viewtopic.php?f=16&t=3484
http://endless-sphere.com/forums/viewtopic.php?f=1&t=32455

Also check that all your connections are tight and not loose.

 

[shorza]

Search this thread, you may find someone who has the same controller and motor as you.
http://www.endless-sphere.com/forums/viewtopic.php?f=2&t=6241

 

[atipene]

SOLVED!

Firstly, thank you so much Shorza for your quick and accurate reply. I would have never thought about altering the phase wiring as they were perfectly colour matched. (Obviously I'm new to this).

After going through the wiring option spreadsheet, I ended up with:

Hall Wires
Motor = > Controller
B B
G G
Y Y

Phase wires
Motor = > Controller
B G
G Y
Y B

I've just spent the last 20 minutes buzzing around the public gardens here, and this thing is awesome! I've never ridden a ebike before, but I ride push bikes all the time (the new ebike is bike#9) I'm already thinking about which of my other bikes I can convert.

Hopefully, after some experience with these things I can contribute to this forum as well.

PS: The 6S liPO setup is perfect for a short commute. I'm going to have the batteries and controller in a small 100x100x200 handlebar bag. Total weight is about 2kg. This bike is awesome!... ok, I think I've said that already

 

[shorza]

Love the eGrin.

Glad i could help. Enjoy it.

 

[dogman dan]

I find it very odd that your halls/phases order was right before, and now it's wrong if you didn't unplug it.

Much more likely is that you found an alternate working combo, but your real problem was just a bad connection in a plug. It may come back, or not. If it does, look hard for the pin that's backed out of the plug housing.

 

[shorza]

Very true. I thought it was strange that all the phase combinations had changed, but none of the halls.

 

[iamsofunny]

I had this problem. It makes like a grinding sound with little power available. It feels like the tire rubs against the swingarm. It's a bad connection from battery to controller. I just resoldered and fit the connectors better.

 

[atipene]

Hi, yes your predictions were right. The problem has come back twice since I last posted. For no apparent reason the motors loses power and makes that horrible grinding noise. Each time I have stopped and changed the phase wires around until I find a combination that works and ride off again. The motor always sounds a little different for a bit after I do this, but then it comes right after about 2-3minutes riding. Something strange is happening for sure. I will rewire all connections and see if I can fix the problem, but is it possible that the motor could ‘shift’ out of phase?

 

[atipene]

... even stranger is that I have lost torque and gained top end speed. Is there some explanation to this?

 

[DAND214]

Is the controller a self learn one ? Like BMSBATTERY ones. If so it still sounds like a bad connection. Halls or phase will drive it crazy.

Just a thought.

Check connections, bad crimp with broken wire in it.

dan

 

[atipene]

I really wouldn't know Dan, I will have to do some research.

 

[atipene]

So I found out that you can check the hall sensors by measuring the voltage across them and slowly turning the wheel. They change from 0 to 5V and this apparently means your hall sensors are ok (?). I did this at the motor and back at the controller, and had readings for all three hall sensors. I think I'm right to say that there is nothing wrong with the hall sensors or the connections.

I was trying different phase wire connections again, and was going ok, but then everything stopped working. I am now only getting a small click in the motor when I power on, but nothing else.

Looks like a new motor and controller might be on order unless there is something obvious I am overlooking.

 

[atipene]

SOLVED (Finally), by buying a new controller. I did open the old controller and looked for bad connections and cracked solder, but that's about as good as my electronics diagnosis gets.

The new controller runs without the Hall sensors, and the bike is back in operation. I love this learning curve.

Thanks everyone.

 

[DAND214]

The new controller runs without the Hall sensors, and the bike is back in operation. I love this learning curve.

Is it a sensorless or a sensored and sensorless? If it has a plug for the halls, you might find that it runs better with the halls. Most of the time there is better power and speed with them.

Dan

 

[atipene]

Thanks for the advice Dan,

Yes it is both sensored and sensorless, so I will plug in the Halls when I get the connector plugs. For now it is running so smooth though (even with load changes), I'm just enjoying having it back on the road. The temperature here in Brisbane is getting up to the 30's (deg C) again, and not having to change clothes when I get to work is great!

 

[atipene]

An with the Halls plugged in now... no noticible difference in performace, but may be getting better battery usage.