BBS02 750w no power to motor

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alexpeterflynn   10 µW

10 µW
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Joined: Mar 29 2021 7:47am

BBS02 750w no power to motor

Post by alexpeterflynn » Mar 29 2021 8:03am

Hi, long time reader first time poster - please be gentle!
I built my ebike with the Bafang mid drive BBS02 750W and for the last 400 miles in 4 weeks of owning it has changed my life. I love it.
Today, I went for a ride with a fully charged battery. Less than a mile into it, I get a 30H code. Turned it off and on again. This happened twice as I was riding back. Then, after a stop, zero pedal assist, it seemed to display a high power demand briefly until I put the anchors on. It lasted less than a second. No throttle was used.
Now, I have a display but no power to the motor (30H is no longer showing). Interestingly, the voltage displays 52v or so, but the battery indicator is red and showing discharged (it is fully charged).
Occasionally on the battery itself, the power LEDs remain on and won’t extinguish without a firm tap. I’m not sure if this is related!
Overall I only ride in fair conditions, dry. I don’t cruise on the throttle apart from the odd blip at low settings.
I’ve checked the connections (I had previously used dielectric grease and liquid electrical tape to seal) - it’s all clean, pins and straight and wires aren’t taught or pinched. I’ve disconnected and reconnected it all.
I’m starting to think it’s a controller issue. Is anybody
Able to offer a little advice? I’m starting to feel a bit out of my depth, but happy to learn with some guidance!

AHicks   1 kW

1 kW
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Joined: Jul 24 2018 10:53am

Re: BBS02 750w no power to motor

Post by AHicks » Mar 29 2021 8:13am

It sounds to me like it's time to drag out the voltmeter and do some troubleshooting/poking around with that? It's the only way you are going to be able to CONFIRM voltage at various points.

alexpeterflynn   10 µW

10 µW
Posts: 5
Joined: Mar 29 2021 7:47am

Re: BBS02 750w no power to motor

Post by alexpeterflynn » Mar 29 2021 8:25am

Thanks. I’ve a multimeter! Is there a guide on where best to start poking around?

docw009   100 kW

100 kW
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Joined: Aug 02 2015 7:43am
Location: Chicago area suburbs.

Re: BBS02 750w no power to motor

Post by docw009 » Mar 29 2021 10:05am

You should tell what display you use, as they may have different error codes between models. On mine, error 30 means no controller communications.

The display is like a stand alone computer. It powers up on battery/ground when you turn it on. It then turns on the controller by applying battery power to one lead. Next, it tries to communicate with the controller, putting up an error 30 if the controller does not answer properly. You're not getting any errors after the display powers up. It could be a bad display. Could be faulty controller.

This diagram has been around forever, but I think it's accurate. If you had a little jumper cable that could fit over the pins, you short pins 1 and 2 in the display connector. That replicates what the display does when it powers up the controller. In the case of the BBS controller, if powered up, throttle will work and whatever you set for PAS 1 will run pedal assist. It's one way of testing for controller functionality w/o a display.
FQzHpBv.jpg
FQzHpBv.jpg (145.35 KiB) Viewed 153 times
Here's the discussion where this has been done.
viewtopic.php?f=6&t=60375&start=100#p1026624

Here's a youtube video attesting to it.
https://www.youtube.com/watch?v=nke-KT60Pcg

I've not tried this with my BBS02, as the pins are a pain in the neck to jumper. I have done the similar trick with other controllers for other bikes, where the connector is female, and it's easy to jumper. Just don't jumper the power to ground. That's disaster.

alexpeterflynn   10 µW

10 µW
Posts: 5
Joined: Mar 29 2021 7:47am

Re: BBS02 750w no power to motor

Post by alexpeterflynn » Mar 29 2021 10:16am

Sorry! I forgot to mention it’s a 850C display. As it’s my first bike and also don’t know anybody locally - I don’t have any access to spares to try and problem solve that way (I live near Colchester, Essex, If there’s anybody that way - I can pay in beer). :P

Jalmassi   1 µW

1 µW
Posts: 1
Joined: Mar 31 2021 11:11am

Re: BBS02 750w no power to motor

Post by Jalmassi » Mar 31 2021 11:18am

Hello there, I have a BBS02 with an 850c and seem to have the same problem. Just wondering if you measured the voltage to the Display ? I tried jumping the pins and got no result. I then measured the volatage over the pins and read 8V. Since then I've been trying to find out what this voltage should be without any luck. Would be interesting to hear how many volts you have.
Regards
Fergus

alexpeterflynn   10 µW

10 µW
Posts: 5
Joined: Mar 29 2021 7:47am

Re: BBS02 750w no power to motor

Post by alexpeterflynn » Mar 31 2021 2:38pm

Whilst not helping the issue - the seller has agreed to send me another controller at no charge. I’ve since opened up the motor and disconnected & reconnected the phase wires, the black socket & the white socket as suggested by a few websites (with no joy to the motor working). Depending on time I’ll try and jump / multimeter it. Will feedback any information.

alexpeterflynn   10 µW

10 µW
Posts: 5
Joined: Mar 29 2021 7:47am

Re: BBS02 750w no power to motor

Post by alexpeterflynn » Apr 12 2021 11:05am

As I’m getting a replacement controller - I thought I’d open up the “spent” controller for problem solving and knowledge. I think I’ve bitten off more than I can chew, and whilst remove some of the potting, I’ve either damaged (or it was damaged) a tiny resistor. Pictures available at request (I’m struggling to upload).

SO, before I cause any more damage, if you think you can redeem this BBS02 750 controller - at the cost of postage, I’d be happy to send it to you (or collect, near Colchester, Essex). Just to attempt not to send it to landfill.

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