Bafang BBS 02 750w strange problem - No Power?

[RoyL]

Went to switch on the bike after a month or so stored in the shed, held the usual button in but nothing on the display. Then checked the 17.5 ah battery - no led lights! Thought it was maybe the battery, took it off checked again it lit up 3 bars out of four and read out 53.3 V.
But when i put it back on the bike it appeared dead again, no led lights nothing.

Im assuming the battery is ok and there`s some sort of short in the cables or motor? Anyone any suggestions ??

 

[Gionnirocket]

Check all your connections for oxidation, arching or any other signs of fouling. They all should be shiny copper color. If not too damaged you can try cleaning with some Isopropyl Alcohol or Contact Cleaner

 

[tomjasz]

Check brake cutout connections. And test their function. A job for continuity tester on your multimeter.
some versions of firmware prevented startup if speed sensor circuit has failed.

OK, rereading, the battery case led lights up when off the base but not when on the base. Sorry I’m confused… It doesn’t make sense…

took it off checked again it lit up 3 bars out of four and read out 53.3 V.
But when i put it back on the bike it appeared dead again, no led lights nothing.

What style case? Pictures of the base connectors and underside battery connectors?

 

[RoyL]

the battery case led lights up when off the base but not when on the base. Sorry I’m confused… It doesn’t make sense…

What style case? Pictures of the base connectors and underside battery connectors?

Shark type Case with standard two pin connector.
When i attach the battery to the bike everything seems `dead`, the `fuel guage leds` dont work..... off the bike the battery appears normal, leds work and reading 53v.
So theres an issue elsewhere, loom or motor .... i`m still think `short` that closes the battery down??

 

[AHicks]

Shark type Case with standard two pin connector.
When i attach the battery to the bike everything seems `dead`, the `fuel guage leds` dont work..... off the bike the battery appears normal, leds work and reading 53v.
So theres an issue elsewhere, loom or motor .... i`m still think `short` that closes the battery down??

I think you have something going on with the battery. The LED's shouldn't care if the battery is on or off the bike. If there was something on the bike side pulling that hard on the battery (hard enough to kill the LED's) you'd see smoke.....

Have you tried charging?

 

[tomjasz]

Shark type Case

Notorious for having bad connectors. Are they clean and showing no corrosion? @AHicks suspicions are worthy of investigation. BUT bad connections can do weird things. If they are blades that fit into slots check the slots and pinch them together so they hold the blades tighter.
How old is the BBSHD? Build date?

 

[tomjasz]

`m still think `short` that closes the battery down??

That would be in the BMS. Who built the battery?

 

[RoyL]

Will check in the morning, have another BBS HD bike with 13Ah battery so i can swap things over and test.... appreciate the suggestions so far

 

[rich c]

I always suggest everyone buys a multimeter to check actual voltage. If the battery measures well, then you start testing the wiring harness. It's an essential tool if you want to troubleshoot and repair DIY.

 

[RoyL]

Took the battery off and fitted it to my other BBSHD bike, it`s perfect, all ok there, battery ruled out.
So it looks like an investigation into the loom or motor? The bike has sat in the shed for a couple of months with temps down to -7C then mild/damp weather, maybe shorting out something? As said above one for the multimeter probably
The Motor is around 6 years old, little mileage tho`

 

[Bobber]

I have the Whale Shark battery. FWIW the indicators do light up when the battery is installed on the bike.
I had a similar "dead" problem. I had expertly installed the wires so that the one going to the display was pinched by the motor as it ran under the bottom bracket. I expertly re-installed it and all was groovy again. Didn't have to do any wire repair either.
Also, did you bring your bike inside? It could have condensation in there.

 

[tomjasz]

My BBSHD builds all sat through Minnesota winters in an un heated garage. For several years. As have my BBS01 builds since 2014. In 7 years of thousands of support emails and calls I saw no…

condensation in there.

The controllers are pretty well protected being potted.

I have seen damaged wiring from being pinched or cinched down to tight by zip ties.
Being 6 years old the firmware may be shutting the motor down with an engaged brake sensor. One of my earliest BBS02 builds had my head spinning for an hour before I realized it wasn’t running due to a brake cutout. Have you tested and confirmed their function?

 

[harryS]

You need a meter to check the voltage. BBS02 and BBSHD are the same, and they use male pins at the display connector, which is a pain.
.
In my experience, if a display doesn't light up, it's not getting battery power. If the power is there, then I would bet it's the three button switch.

.

 

[RoyL]

We seem to have lift-off! Took the bike inside and prised apart all those multi-pin connectors on the loom, refitted and all back working as it should.
Not being able to pin it down to one particular thing however is worrying... maybe the freeze/thaw/damp had got into the loom - don`t know, will keep an eye on it.

Appreciate all the tips.

By the way anything i could spray the loom with, sealer or the like to keep dampness out?

 

[tomjasz]

By the way anything i could spray the loom with, sealer or the like to keep dampness out?

Boeshield or ACF50 both are used on avionics MilSpec and general aviation

 

[harryS]

Maybe some frost under the center button. Probably a membrane switch, maybe a metallized rubber contact on top of bare copper on a circuit board,

 

[Gionnirocket]

I'd say gremlins... but probably a fouled connection and cycling it apart and together again was enough remove some contaminate to regain continuity. Once you have one, they typically return with more and more frequency... but that's not an absolute.
When you have it in a warm place to work I'd inspect and clean as necessary. Then protect it as @tomjasz says on the mating rubber parts of the connectors.