Bafang BBS01 - Connector Problem?

[Aushiker]

I am in the process of transferring my Bafang BBS01 motor from one bike to a new one. I have installed the motor and started wiring up it but have struck a problem similar to what teslanv reported in this video ...

I am getting a crackling sound coming from the motor, the battery indicator flashes empty on the display and the display shuts down. The connectors are the same as on the original bike which had been working okay till my last ride when the motor lost power. At the time I put it down to a flat battery as I had forgotten to charge it fully at work but now I am not so sure.

Anyway I have had a play with the multimeter and tested the power cable. With the cable disconnected from the motor I am measuring just over 41v however when I plug the cable into the cable coming from the motor and then push the probes into the back of the connector (Anderson) on the motor side, the voltage reading drops to around 31v. I am pretty sure I am getting a good connection with the multimeter as I can see the metal parts of the connector. I am guessing the voltage should not drop so does this sound like a connection problem?

Thanks
Andrew

 

[Geebee]

With a voltage drop that extreme the only possibilities are connector or the battery pack has a major issue, this assumes you have tried to charge the pack, it should not be showing 41v if flat but it would explain the 31v with a light load.
Can you get onto the battery side connection to measure? it would eliminate the connector.
Or hook the battery upto another load ad see if the voltage drops, something like 3x 12v globes in series?

 

[Aushiker]

Thanks. I measured the voltage at the battery and each connection point (two of them as I had to build a long wire for the recumbent). All good except for the last connection point to the motor cable.

I have had fuse issues and it has been suggested to replace the fuse holder with a better quality one. However when the fuse is not working I get about 1.2 volts reading at the battery output so I am guessing that is not the problem.

Today I will unbundle the connector and take a look. May swap it out for a pair of XT60 connectors as I have some on hand I think.

Andrew

 

[Geebee]

Thanks. I measured the voltage at the battery and each connection point (two of them as I had to build a long wire for the recumbent). All good except for the last connection point to the motor cable.

I have had fuse issues and it has been suggested to replace the fuse holder with a better quality one. However when the fuse is not working I get about 1.2 volts reading at the battery output.

Andrew

If the power measures correct when plugged in before the motor connector and bad after it, it has to be the culprit, assuming I read your reply correctly
Can you use a couple of wires to bypass it, to test everything is working ok?

I extended my connector by soldering to the motor wires so as not to add an extra connector in the power leads.
Connectors, fuses and there holders have been the most unreliable parts of e-bikes I have owned.

 

[Aushiker]

Just pulled off the Anderson housings from the motor side and checked the crimp. Crimp looks okay so with the housings off I simply pushed the contacts into the battery side and bingo proper connection. Not sure what is causing the connectors to not connect properly but.

Andrew

 

[Aushiker]

I extended my connector by soldering to the motor wires so as not to add an extra connector in the power leads.

I need to re-do the wiring for this bike (shorter for starters + want to add in a watts-meter) so I will look at doing what you suggest with the aim of having a single connection point.

Thanks for your help.

Andrew

 

[Geebee]

Glad that your rides up and running, they are an awesome assist unit.