BAFANG BBSO2 MOTOR PROBLEM

[brianw]

I have just sold my e-mountain bike with Bafang BBSO2 500w motor.
I had three years trouble free riding on and off road, gentle riding using only low to medium power levels ie max power 5 of 9.
Unfortunately the new owner had a problem after his first ride home of only 5 miles. Before this ride, on testing the bike, he was riding a reasonably steep hill, several times to demonstrate the high power levels the motor can produce. I suspect he was using high to max power on his way home also. The battery meter was showing only one bar on arrival home. He replaced the batteries but although the monitor lit up momentarily there was no power. On fitting recharged different batteries the same thing happened.
I am trying to help sort out the problem.
I have an identical bike and motor with which I have swaped monitors and wiring harnesses with his.
My monitor works on his bike but no power to PAS or throttle
His monitor does not light up or power up my bike

I'd be interested to know other riders experience or experts views on what has blown?
Thanks for taking the time to read my ramblings.

 

[Woosh]

His monitor does not light up or power up my bike

the LCD contains the switch to turn the controller on.
That seems to say that his LCD has gone.

My monitor works on his bike but no power to PAS or throttle

try using your bus cable with your LCD, leave brake levers and throttle out, then use the walk mode to test the controller and motor.

 

[Deleted member 4366]

If his LCD doesn't work on your bike, but does switch on, the CPU in it is most likely fried. If your working LCD doesn't give power to his bike, then his controller is most likely fried, but the problem could also be that the motor's hall sensors are fried, which has caused the consequential damage. You'll have to test them before thinking about a new controller.

So, take off the controller and test the hall sensors first, then try a new controller and LCD.

To test the hall sensors, you have to disassemble the motor so that you can turn the shaft. I used a spare 5S balance lead, which has the same connector as the halls. I use a pack of three AA cells to power the halls while testing.

That sort of damage can also come from tying the LCD harness too tight with cable-ties. If the battery wire touches one of the data or 5v wires, just about everything can get wiped out.

Another problem you can get is water in the controller compartment, which can have all sorts of consequences. If you've recently used it in the wet, that would be my first bet.

 

[brianw]

If his LCD doesn't work on your bike, but does switch on, the CPU in it is most likely fried. If your working LCD doesn't give power to his bike, then his controller is most likely fried, but the problem could also be that the motor's hall sensors are fried, which has caused the consequential damage. You'll have to test them before thinking about a new controller.

So, take off the controller and test the hall sensors first, then try a new controller and LCD.

To test the hall sensors, you have to disassemble the motor so that you can turn the shaft. I used a spare 5S balance lead, which has the same connector as the halls. I use a pack of three AA cells to power the halls while testing.

That sort of damage can also come from tying the LCD harness too tight with cable-ties. If the battery wire touches one of the data or 5v wires, just about everything can get wiped out.

Another problem you can get is water in the controller compartment, which can have all sorts of consequences. If you've recently used it in the wet, that would be my first bet.

Thanks Woosh and d8veh for quick response
I need to get my terminology to match yours.
LCD is the display screen and on/off switch on the bars
Bus cable is the main multipin connector from the motor to the LCD

OK His LCD doesnt work at all My LCD lights up on His but no power
My bus cable does not work on His

Where is controller situated? If in motor housing, can it be accessed with motor on bike?
The bike has not been out in wet conditions and it's hard to imagine a tight cable has occurred between test ride and His home ride

Has this problem occurred by high power level and low cadence or is it something that just happens?
Thanks again

 

[wheeliepete]

With all the switching around of batteries, has he connected one of them the wrong way round? Did all the batteries have the same connectors and of the correct voltage? If he arrived home under power it seems very strange that the system has died with the bike stationary. The controller can be damaged under full power and low cadence, but this normally happens when you are riding and does not damage the LCD.

 

[Woosh]

Has this problem occurred by high power level and low cadence or is it something that just happens?

quite possibly. People who don't have experience of CD bikes don't realise how much heat is generated inside the motor if they don't keep their cadence up. There ought to be a label on the handlebars reminding riders 'be nice to your motor, keep your cadence above 60 rpm'.
The controller is inside the motor.
I would recommend you rule out easy to rectify faults like throttle and brake sensors. Connect only the main cable to the LCD and long press the - button for 2-3 seconds. If the motor does not start, your controller is gone. These controllers are very difficult to repair, I don't even try, just send them back to Bafang factory.
Hall sensors are unlikely to go, I have not replaced even one on all the BBSes that we sold over the years.

 

[brianw]

With all the switching around of batteries, has he connected one of them the wrong way round? Did all the batteries have the same connectors and of the correct voltage? If he arrived home under power it seems very strange that the system has died with the bike stationary. The controller can be damaged under full power and low cadence, but this normally happens when you are riding and does not damage the LCD.

Thanks Wheelie
The problem is that I am talking to the father, it's his son who rode home on the bike, neither have any experience of ebikes. I'll ask him tonight if the bike had power when he got home.
The battery connectors are Anderson so unless he connected red to black that should'nt have happened. He did say on connecting the recharged batteries, after the first failed attempt that the LCD flashed up what he described as 'dots all over the screen for a second and then nothing'
I.m going to try Woosh's suggestion of hooking up my bus connection
Let you know what goes

 

[wheeliepete]

'dots all over the screen for a second and then nothing'

Hmm, that don't sound good When you say batteries, are they lipos?

 

[brianw]

the LCD contains the switch to turn the controller on.
That seems to say that his LCD has gone.


try using your bus cable with your LCD, leave brake levers and throttle out, then use the walk mode to test the controller and motor.

Thanks again for your help
Just tried the walk test no joy, so the controller is fried, as d8veh would say.
Can I get the controller out with the motor on the bike?
Does a blown controller mean the LCD is also gone , as it does not work on my mike?

 

[brianw]

Hmm, that don't sound good When you say batteries, are they lipos?

Yes 5cell 5Ah and work well on my bike

 

[Woosh]

Can I get the controller out with the motor on the bike?

not easy.
It's quicker to get the motor off the bike first, you can leave the chainring where it is.

 

[brianw]

With all the switching around of batteries, has he connected one of them the wrong way round? Did all the batteries have the same connectors and of the correct voltage? If he arrived home under power it seems very strange that the system has died with the bike stationary. The controller can be damaged under full power and low cadence, but this normally happens when you are riding and does not damage the LCD.

Hello again Wheelie
Just got the full tale of the fatal bike ride. When the son ,Adam got home he said'the bike was going great but he had to pedal a lot harder at the end'
Ie, little or no power but the LCD was working as normal showing one bar out of five.
An unknown state of charge battery was then connected and nothing worked.
Two sets of batteries were connected and motor power up on throttle.
(one 'battery' as I have used it is two 5Ah lipos in series, this second set is two more in parallel)
For some reason he resorted to the one battery again and this time he got the LCD screen' filled with small squares', then all went off
From your previous post it confirms that the breakdown did not happen on the ride, but this version confuses me even more
Any ideas?
PS have you seen Woosh's post and my reply?

 

[wheeliepete]

Ok, so pedaling harder all sounds good, just the voltage dropping off and less power. I'm not clear on the battery bit. I am going to assume that you only gave him one battery pack which consisted of 10x3.7v lipos=37v. The other battery was his? made up of ?. What voltage? Dosn't sound like they made any attempt to measure the voltage of the combined batteries before connecting them to the controller or how they were connected together, so who knows what happened. Yes, saw the posts. all you can say for certain is it's broke!!

 

[wheeliepete]

As far as removing the controller goes it can be done with drive on the bike. Pop the chain wheel off, 5 allen bolts, remove the 3 allen bolts on the ali casing(controller). It makes the job easier if you also take off the plastic secondary drive cover(3 allen bolts) Pull the controller away from the motor gently. 3 large wires to disconnect, then 2 small connectors that are usually siliconed in place, so carefully cut away the silicon before trying to remove them.

 

[brianw]

Ok, so pedaling harder all sounds good, just the voltage dropping off and less power. I'm not clear on the battery bit. I am going to assume that you only gave him one battery pack which consisted of 10x3.7v lipos=37v. The other battery was his? made up of ?. What voltage? Dosn't sound like they made any attempt to measure the voltage of the combined batteries before connecting them to the controller or how they were connected together, so who knows what happened. Yes, saw the posts. all you can say for certain is it's broke!!

No I gave him three sets of 2 times 5 cell Lipo's, to be honest, the sale happened so quickly, he was mad keen to get on the bike, I am not sure what charge the batteries had.
His experience of bike electrics is very limited.
Thanks for your later post, that's my job for tomarrow
Cheers

 

[Deleted member 4366]

Sure as anything, he connected those batteries incorrectly somehow. Only he knows what he did.

Were your Anderson connectors completely fail-safe?

Was it possible to get series and parallel harnesses mixed up?

 

[brianw]

Sure as anything, he connected those batteries incorrectly somehow. Only he knows what he did.

Were your Anderson connectors completely fail-safe?

Was it possible to get series and parallel harnesses mixed up?

Yes it is possible to mix them up but he would still have had to connect a red to black. would that have left signs of a fryup?

 

[Nealh]

Probably a few causes likely that he has fried the controller, a combo of low cadence or too high a gear. Also being in the wrong pas level up hill may not help as well as this will also labour the drive unit.

Multiple lipo's connected wrongly up in series will cause over volting and blow the in main rush capacitor, the controller would have a distinctive gunpowder/sulphur type smell when removed.

 

[brianw]

not easy.
It's quicker to get the motor off the bike first, you can leave the chainring where it is.

not easy.
It's quicker to get the motor off the bike first, you can leave the chainring where it is.

Ready to start removing controller but I'm confused,no surprises there.
Is the controller on the '8FUN' side or the chain wheel side?
Wheeliepete is telling me to take the chain wheel off first

 

[Deleted member 4366]

If he connected series instead of parallel or if he connected with reverse polarity, the capacitor on the controller would blow - normally with a bit of a bang and some horrible smoke, so it's pretty obvious at the time. You should be able to see that when you take the controller off. The components are potted in silicon, but I think you'll still see and smell evidence of it.

Controller is the pod behind the chainwheel that's held on with three screws.