A Desperate Bafang E-bike rider from Germany urgently needs your help!

[stesie1001]

Hello,
I urgently need your help! I'm from Germany, unfortunately there aren't many e-bikes with Bafang motors in Germany! If there are problems with the electronics, like with my e-bike, you won't find a workshop that can help you! I bought a rear wheel with Bafang hub motor, controller, battery, wiring harness and display from Alibaba, all as a complete set! UART protocol! After installing it, I drove happily for 70 km without any problems, until the motor suddenly stopped! An error message came up with overvoltage protection! At the time I was traveling at about 15 mph, without thumb throttle! Because I thought the controller had been damaged, I ordered a new one and installed it! But the same problem! The display starts up normally, but when I then move the thumb throttle or pedals, the error message comes up immediately, overvoltage protection! I bought the Besst Tool from Bafang! Connects to the display, which is also read! If the battery or the controller is then to be read, it says that no connection is possible! I hope you can help me!? Many thanks for your support! Greetings from Germany Stefan
As my English is not the best, I asked Uncle Google for help!

 

[stesie1001]

Definitely in English! My translator changed it, I hadn't noticed!

 

[HumanPerson]

Definitely in English! My translator changed it, I hadn't noticed!

No worries

 

[m@Robertson]

Should I attach that?

No. You've changed the display and still have the error, so we know the error is not in the display.

 

[Annieolnie]

So now you are down to codes 07 and 08. This has never happened to me before but this what Google is saying about it.

 

[Annieolnie]

I guess it is time to test some hall sensors. Have you done that before?

 

[m@Robertson]

I guess it is time to test some hall sensors. Have you done that before?

There are no accessible hall sensor wires on a Bafang motor. They are there and contained within the 9-pin HiGo motor plug. You cannot probe for voltage on a plug like this when its connected, the way you could if the connections were JST. To see the pinout, follow this link:

Connectors - Learn

There are lots and lots of connector types used in the ebike industry, so many that it would be a very tall order to try and list them all. In our business, we focus just on aftermarket conversion kits and have tried to keep the connector styles down to a well chosen minimal set. This page...

ebikes.ca

and scroll down to the HiGo Z910 entry.

This is a rather old discussion of the test procedure for a Bafang motor. Its not a procedure well suited to the noobie.

Testing hall sensors INSIDE hub motor (bafang)

Hey guys, can you please just confirm that I am checking the hall sensors the right way - inside the motor? As you can see from the pictures I cannot tell which colour is which sensors - therefore I have no way of knowing which to replace.. How do I test it inside? I have measured from the...

endless-sphere.com

 

[Annieolnie]

So, what do you think the next step should be?

 

[stesie1001]

Controller, display, cable, and hall sensor have been newly ordered!! Once delivered, we can continue!

 

[HumanPerson]

So, what do you think the next step should be?

My honest opinion would be to get a whole new kit so they can ride, then fix or bin the one
that doesn't work now.
Just my opinion 'cuz if it were me i'd have wanted to ride already LOL

Unless they like to tinker with stuff and have nothing to ride for

 

[Annieolnie]

Controller, display, cable, and hall sensor have been newly ordered!! Once delivered, we can continue!

Did you open up your motor to check your hall sensors?

 

[m@Robertson]

My honest opinion would be to get a whole new kit so they can ride, then fix or bin the one
that doesn't work now.
Just my opinion 'cuz if it were me i'd have wanted to ride already LOL

Unless they like to tinker with stuff and have nothing to ride for

Yeah I agree. We are going back in the direction I originally pointed to: Just replace stuff rather than flail around in the dark. Then diagnose on the bench. But based on what @Annieolnie dug up on the formerly-mystifying error message, the problem could be the motor itself, so this could end up needing a new G020.500, and put the new, hopefully good motor core it into the existing wheel and motor casing.

Ordinarily, you replace the cheapest stuff first and work your way back one item at a time. In this case it may be the most expensive thing (the motor) is what should have been started with. MAYBE. A rare occurrence as Bafang motors tend to be bulletproof.

So, what do you think the next step should be?

See above. I wouldn't be messing around with removing a hall sensor on a PCB and soldering on a new one. If its the motor, I would replace it. Get back on the road, then spend a lazy Saturday with the soldering iron etc. A spare motor can always be a good thing to have if you rely on your bike. I actually bought a spare G020 once when it turned out I had to leave a motor with a wheelbuilder for a few months. That project got finished, and two years later I was able to use the motor on a new bike build, so it didn't go to waste.

 

[stesie1001]

Let's wait until the new parts arrive! Then there won't be much left except the motor! I have an old e-bike here, the Bafang hub motor has done 21,000 km! It was still running, but the bearings were completely worn out! And the new one after 70 km?

 

[Annieolnie]

Well, a new core would be around $ 140.00 U.S. which isn't too bad
for the price of a learning experience. Let us know how it goes.

 

[Annieolnie]

Yeah I agree. We are going back in the direction I originally pointed to: Just replace stuff rather than flail around in the dark. Then diagnose on the bench. But based on what @Annieolnie dug up on the formerly-mystifying error message, the problem could be the motor itself, so this could end up needing a new G020.500, and put the new, hopefully good motor core it into the existing wheel and motor casing.

Ordinarily, you replace the cheapest stuff first and work your way back one item at a time. In this case it may be the most expensive thing (the motor) is what should have been started with. MAYBE. A rare occurrence as Bafang motors tend to be bulletproof.

See above. I wouldn't be messing around with removing a hall sensor on a PCB and soldering on a new one. If its the motor, I would replace it. Get back on the road, then spend a lazy Saturday with the soldering iron etc. A spare motor can always be a good thing to have if you rely on your bike. I actually bought a spare G020 once when it turned out I had to leave a motor with a wheelbuilder for a few months. That project got finished, and two years later I was able to use the motor on a new bike build, so it didn't go to waste.

I think, you are right in that there should be some decent spare parts in all of this, almost enough for a second bike.

 

[jsbraga]

I would go back to square 1 and start over again by being sure everything is properly seated, battery correctly inserted, battery at the correct voltage, and all connections properly secured. We are all guilty of tail chasing and quickly lose sight of where we began. The battery being in compliance, with the voltage being in the correct range is paramount. It’s very possible that the charger has overcharged the battery, which could easily happen. Good skills moving forward.

 

[Annieolnie]

I would go back to square 1 and start over again by being sure everything is properly seated, battery correctly inserted, battery at the correct voltage, and all connections properly secured. We are all guilty of tail chasing and quickly lose sight of where we began. The battery being in compliance, with the voltage being in the correct range is paramount. It’s very possible that the charger has overcharged the battery, which could easily happen. Good skills moving forward.

Have you looked at all the screen shots on page 1 and 2? Battery was at 52.6v. Display showed five codes. Codes were then erased, two codes repeated with that voltage. Perhaps your computer is not loading the pictures.

 

[m@Robertson]

And IIRC he already did the double-checking. Still, its fair to say there is some tail-chasing going on here. Some of that is I think unavoidable given the unique nature of this particular problem. It looks like the problem here is the one thing it almost never is: The Bafang motor itself, and not the ancillary bits that are commonly of iffy quality at best.

If I were starting over again:

1. Test the battery with a voltmeter to confirm the display is telling the truth and it really is 52.6v (or close to it).
2. Has the bike been laid down (crashed on its side) so the motor cable has been damaged? If so, fix the wires. Also check the wires' entry at the point of ingress to the motor to ensure for example the motor was not put in upside down and thus the wires are bent over the opposite side from the hollow axle cutout in the side. They can break if you do that.
3. Looking at the merry go round of errors, they could point to a bad controller or a bad wiring harness feeding crap to the controller. Replace the wiring harness only.
4. Next, since a new lowest-cost item (wiring harness) didn't work, replace the controller.
5. Is there a motor extension cord between motor and controller? Replace it.
6. If still no joy, replace the display with something as cheap as possible to eliminate that element in the chain of data custody.
7. At this point, given the errors, we are left with the motor itself and bypassed the throttle, PAS sensor and brake cutoffs since they don't seem to be involved here.

If it were me at Step 2 I would, as I say above swap out everything but the motor for parts I know inside and out.

I do have extra motors on hand, along with throttles, sensors and controllers. I have a lot of bikes so this isn't as crazy as it sounds, and having a deep bench to pull parts from has paid dividends many times. But... this approach doesn't make a lot of financial sense for the single-bike owner who bought their bike, didn't build it themselves and is only a recreational rider.

NOTE: Item 2 above is new.

 

[jsbraga]

Have you looked at all the screen shots on page 1 and 2? Battery was at 52.6v. Display showed five codes. Codes were then erased, two codes repeated with that voltage. Perhaps your computer is not loading the pictures.

Good skills to ya.