Help! Replacing a Bafang controller with different connectors

[Shaathy]

Hi - I’m really hoping someone more tech savvy will be able to help me. I bought a Buzzbike H700 from Wiggle a year or so ago. It has been great but unfortunately now has stopped working and is giving me an error message which is listed as “overcurrent to the controller”. Having done some research, I am pretty sure I need to replace the controller, which would be easy enough except that I have searched Ebay/Amazon/Alibaba and cannot find a controller with the same connectors.
I’ve tried contacting Wiggle, Bafang and three or four different ebike repair shops - no help forthcoming (no reply from Wiggle and Bafang, none of the e-bike shops cater for this bike).
Here’s my question: if I purchase a controller that has all the right specs but different connectors just for the PAS and display, is there a way to jimmy it together e.g. with some kind of generic connectors? Does anyone have any experience if doing anything like this? I would be incredibly grateful for any helpful advice.

BTW, I am aware this is the issue with buying a cheap ebike rather than a quality brand, but unfortunately budget didn’t stretch to something made in Europe.

 

[thelarkbox]

Try this chap https://www.pedelecs.co.uk/forum/threads/10-off-new-uk-diy-e-bike-parts-kits-website.48584/#post-742160 for bafang connectors and perhaps a controller ?? At least no translation difficulties in email/phone exchanges..

Ive only browsed the site, seems to be charging reasonable prices and honest about in-stock thats is numerous items tagged out of stock - which is understandable for a start up..

 

[thelarkbox]

Btw whats wrong with the controller?? it may be worth leaning on the collective wisdom in here to confirm whats what before spending??

 

[Nealh]

Over current will mean controller mosfet failure .

Those connectors are Higo's which Bafang use all the time , Higo are a Belgian company.

Is the battery a generic two wire one or does it have comm's ?

If generic tbh it would be an ideal situation to change the speed control bafang set up to nice KT current control set up. If one has the std hub motor 9 pin motor connector then buy a nice KT controller kit for about £80 - £100 form topbikekit.com.

 

[saneagle]

Hi - I’m really hoping someone more tech savvy will be able to help me. I bought a Buzzbike H700 from Wiggle a year or so ago. It has been great but unfortunately now has stopped working and is giving me an error message which is listed as “overcurrent to the controller”. Having done some research, I am pretty sure I need to replace the controller, which would be easy enough except that I have searched Ebay/Amazon/Alibaba and cannot find a controller with the same connectors.
I’ve tried contacting Wiggle, Bafang and three or four different ebike repair shops - no help forthcoming (no reply from Wiggle and Bafang, none of the e-bike shops cater for this bike).
Here’s my question: if I purchase a controller that has all the right specs but different connectors just for the PAS and display, is there a way to jimmy it together e.g. with some kind of generic connectors? Does anyone have any experience if doing anything like this? I would be incredibly grateful for any helpful advice.

BTW, I am aware this is the issue with buying a cheap ebike rather than a quality brand, but unfortunately budget didn’t stretch to something made in Europe.

You shouldn't buy or change anything until you've tested what's wrong, otherwise you just waste your money.

Here's how to test an ebike:
1. Measure the voltage at controller's battery connector. Obviously should be battery voltage. 36v - 42v for a 36v battery would be an acceptable range, but if you've fully charged the battery and it's less than 41v, it needs some sorting.
2. Measure the voltage on the 5v rail. You can measure that between any ground (black) and any of the reds going to throttle, PAS or motor halls. It should be around 5v.
3. Check throttle signal wire voltage on it's connector while connected. it's the wire that's not red or black on the throttle connector. Should give about 1v to 4v when you twist the throttle. If there's more than one wire, your meter will find it. It's the one that's between 1v and 4v, assuming that it works.
4. Check that the pedal assist sensor is pulsing. Measure the PAS signal wire while turning the pedals slowly. Should pulse 5v on and off every time a magnet passes the sensor. The signal wire is the one that's not red or black.
5. Check the motor hall signal wires (blue green and yellow) on the motor connector at the controller. They should each pulse with 5v going on and off as you rotate the wheel BACKWARDS.
6. Mosfet test. Disconnect the motor cable and battery from the controller. Measure the resistance (200k scale) between the red battery connection and each of the three phase wire connections, then repeat with the black battery wire. Each set of 3 readings should be the same as each other and in the range 7K -24K. Though can be higher as long as they're all the same. Due to the capacitor across the battery wire, you can get a constantantly changing measurement while it charges. In that case, try swapping your probes round. Even though can be a moving result, the only important thing is that all three move in a similar way.

To test whether it's working, you should disconnect everything that's not needed, like Pedal sensor, lights and brakes. Listen for a tick or click from the motor when you operate the throttle, which indicates incorrect timing of the power pulses caused by incorrect connection sequence or faulty connection in the motor cable.

If your bike passes all those tests, it should work, so then you can look at any settings or other logical causes, like stuck brake switches, PAS installed backwards.

 

[Raboa]

If you mean the bullet connectors from the controller, this is an old post discussing this. You can get plastic boxes which has gel inside that the connectors fit into

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