8fun BBS02 not switching on

[jonnybump]

Hi all
I purchased a BBS02 750w motor last year and have covered around 1000 miles on it so far. Last week I was performing routine maintenance in the bike during my lunch break, and when I finished work I went to get my bike and noticed that even though the display was working, I was getting error 30 problems. I proceeded to ride the bike unpowered when all of a sudden it kicked back into life albeit with no speedo reading. I had a few error 21s on the ride home but power was fine.

I went to leave to work this Monday and there was no life in the system at all. Even the display won't switch on. I checked the battery fuse and sure enough it had blown. Tried a new fuse, pressed the power button on the battery and it blew the fuse instantly.

Unplugged the motor and controller and put new fuse in the battery and switched it on, and the battery doesn't blow the fuse, but as soon as the controller and motor are connected, it blows the (30a) fuse.

I've stripped the kit from the bike so I can use it normally for the time being.

Anyone know what could be the problem? I have a multimeter if anyone can guide me at all.

Many thanks
Jon

 

[trex]

Error 30 usually shows up if you have a damaged cable between the controller and the LCD. That could be caused by humidity shorting the signal wires.

 

[Deleted member 4366]

There's been a quite a few reports of blown MOSFETS in the controller. It seems that they're not up to the job, especially if you use the maximum power. If blown, the controller will see the same fault as a short or damage in the motor wire, so your error code is consistent with that. You have to dismantle the motor to test it. You can buy a replacement controller from various sources. I don't know if anybody does an upgraded one yet.

 

[jonnybump]

Thanks for that. So if I remove the controller from the motor, remove the potting compound and check for continuity between the mosfets, it should tell me if that's what's at fault?

In the event 8fun aren't willing to supply a replacement controller do you know who can supply them as I've done a quick search and come up with only international sellers.

Thanks
Jon

 

[Deleted member 4366]

You don't need to unpot anything yet. You can get a good idea about whether the FETs are blown by measuring the resistance between each phase wire and each battery wire so that you get six results.

 

[jonnybump]

Okay my results are:

Battery Negative -
Green - 3.5kOhm
Yellow -
Infinite
Blue - Infinite

Battery Positive -
Green - 2.5kOhm
Yellow - Infinite
Blue - Infinite

Does this point then to a controller/mosfets issue?

Thanks for your help so far
Jon

 

[Deleted member 4366]

Yes, assuming that you measured correctly. All the ones I measured on other controllers were in the range 7k to 14k, but to each battery wire, the three results should be the same, so something is definitely wrong.

 

[Deleted member 4366]

https://bmsbattery.com/ebike-kit/687-inner-controller-for-bbs01-02-central-motor-ebike-kit.html

http://em3ev.com/store/index.php?route=product/product&path=46&product_id=188

 

[jonnybump]

https://bmsbattery.com/ebike-kit/687-inner-controller-for-bbs01-02-central-motor-ebike-kit.html

http://em3ev.com/store/index.php?route=product/product&path=46&product_id=188

Seems that's only for 36v500w and mines a 48v750w. Really struggling to find someone that can supply these replacement controllers in the UK

 

[Deleted member 4366]

This one is definitely the 48v 750w one:

http://em3ev.com/store/index.php?route=product/product&path=46&product_id=188

I very much doubt that you'll find one in the UK.

 

[Kinninvie]

If you have a 6 fet controller contact the supplier and they may send you an upgraded (9 fet) replacement foc.
Even if you have had it quite a while there is no harm in trying.