BBSHD turns off and won't turn back on

Dynz

Member
Region
United Kingdom
I plan to investigate this afternoon when I'm free, but wanted to state my findings here as some of you will definitely have a few ideas on what could be wrong.

So, yesterday I went on an amazing ride for a few hours exploring the rural area outside the town I'm in. About 10 mins before I decided to head back home (luckily I had just made it UP a huge hill) the display and motor just shut down instantly. There were no alerts, voltage/battery seemed to be fine.
I pedalled back home and plugged in the battery immediately and went to check the remaining voltage. It was 49 something volts. Thinking the new display I just got a week prior might misread the voltage, I left it on charge surprised to see It was fully charged to 54.4V just a few hours later. I unplugged the charger and managed to turn the display on again which was a relief. I went into the settings on the display and the battery was still correctly set to 48V. But then when I gave the throttle just a tiny bit of juice it shut down instantly, and it won't come back on. The indicator on the battery itself works and indicates it's fully charged.

My riding style yesterday was very little throttle if any, and I did do a ton of pedalling on highest PAS setting (I'm using the 3 modes).

This afternoon I plan to check on the SW102, as I hope the new 500C I got is what's faulty. I should probably mention that I only got about 3 rides on the new display. If switching displays doesn't work I might check the programming settings on my PC.

Would love if any of you savvy lot on here could help me out with this. Cheers!
 

Gionnirocket

Well-Known Member
Region
USA
City
Y. O.
Your plan seems good.
Swap out the display and double check all connections, even the battery into the mount.
 

Dynz

Member
Region
United Kingdom
Ok so switched the displays out, but still nothing. I then connected the wiring harness to my PC. It looked like the unit was recognised as it showed up under Devices so I had some hope. But it even showed when turning the battery off with the cable connected so nope. It wouldn't connect.
IMG_20210606_163150.jpg

IMG_20210606_163721.jpg

The other thing I could think of is a while ago I shortened the cables between the unit and the battery mount. It was giving me some issues at first but after I properly heat shrink wrapped the connections - no problems after that. Maybe I should consider soldering?
I did have to go over a bit of wet mud after my last ride but that was well before it actually shut down.
This is pissing me off lol.
 

Gionnirocket

Well-Known Member
Region
USA
City
Y. O.
Have you tested to see if V is leaving the battery and making it to the controller?
Your going to need to open up a splice or the controller.... Or you can puncture the wires with a neddle.
I've never had a good quality butt splice go bad and though soldering large wires is doable, it does require a lot of heat to get a nice low resistance connection. Crimping is much more efficient.

Edit:... The device showing up on the pc is the USB/Serial cable... Not the controller
 

Dynz

Member
Region
United Kingdom
Any
Have you tested to see if V is leaving the battery and making it to the controller?
Your going to need to open up a splice or the controller.... Or you can puncture the wires with a neddle.
I knew not attaching them properly was gonna bite me in the ass. I had basically just intertwined the cables then shrunk some heatwrap over them, and put some tape over both cable connections. It seemed sturdy enough but I guess probably nothing a ton of vibration couldn't loosen.
As for a voltage meter, any specs I should look out for when buying one? I'll get a crimper and stuff as well.

Edit:... The device showing up on the pc is the USB/Serial cable... Not the controller
Yeah that's what I realised after turning battery off.
 

Gionnirocket

Well-Known Member
Region
USA
City
Y. O.
Any

I knew not attaching them properly was gonna bite me in the ass. I had basically just intertwined the cables then shrunk some heatwrap over them, and put some tape over both cable connections. It seemed sturdy enough but I guess probably nothing a ton of vibration couldn't loosen.
As for a voltage meter, any specs I should look out for when buying one? I'll get a crimper and stuff as well.


Yeah that's what I realised after turning battery off.
Buy the best one you can afford. Here Fluke is a good tool.
That said, I have an $8 from Aliexpress that has been working just fine 🤣
Most all do the same basic things.

Example: https://www.harborfreight.com/30-pa..._SKJdUU-b_BFkbKYUWK4Axsjy3DDx1u0aApV6EALw_wcB

Best style of basic crimper:
 

Dynz

Member
Region
United Kingdom
I had basically just intertwined the cables then shrunk some heatwrap over them, and put some tape over both cable connections. It seemed sturdy enough but I guess probably nothing a ton of vibration couldn't loosen.
I'm actually lying, just remembered I did actually use some butt connectors but the middle connection bit of them was a bit too thin so I'd kinda forced both ends in there and used pliers to squeeze the lot together.
I've ordered a multi meter and will have to wait until it gets here. The uncertainty is killing me 😭, I hope nothing's too fucked, the weather over here is finally behaving.
 

PedalUma

Well-Known Member
Region
USA
@Dynz,
Can you post photos? Are there any wires routed between the frame and the motor? The mention of water could be a significant clue here. I wire from inside the motor housing directly to inside the battery connector. Soldered and sealed at both ends. Here is a 1983 Specialized built that way.
 

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Gionnirocket

Well-Known Member
Region
USA
City
Y. O.
I'm actually lying, just remembered I did actually use some butt connectors but the middle connection bit of them was a bit too thin so I'd kinda forced both ends in there and used pliers to squeeze the lot together.
I've ordered a multi meter and will have to wait until it gets here. The uncertainty is killing me 😭, I hope nothing's too fucked, the weather over here is finally behaving.
If the butt crimp was poorly done and not sealed well, and then you got moisture in there... A high current draw like a long hill could have caused it to fail...
But then again, maybe you cooked the controller 🔥😈🔥muahahaha...
If you plan on redoing the connections, no harm in opening them up now to see what they look like.
As @PedalUma suggests... Maybe some pics
 

Gionnirocket

Well-Known Member
Region
USA
City
Y. O.
Was a warm day actually. Please don't say that :eek:
I'll upload some pics soon.
Just messin'
And don't worry... it's usually the easiest and most obvious.
As far as the pics, You gotta do something.... I mean I gave up on the wheelie video. If not the wiring at least some of the local ladies 🙃
 

Dynz

Member
Region
United Kingdom
Ok so here's some pics after having removed the battery and cable sleeve. As you can see both connections are quite tight and not exposed at all, heat wrap + self-amalgamizing tape + electrical tape over it and a little zip tie to keep them in place. Over that i had the cabe sleeve. It was just a tiny bit of mud i went over as well (bike's pretty clean as you can see).
One thing I did forget about is the two redundant cables i had zip tied to the frame under the battery (light connector and capped connection for brake sensor i presume). Perhaps that is where the issue is.
I'm still awaiting my voltage meter so it's all hypotheses for now.
IMG_20210607_191930.jpg

IMG_20210607_192011.jpg
 

Gionnirocket

Well-Known Member
Region
USA
City
Y. O.
Don't think it the capped off cables as the timing of a short there and your sequence of what happened would be pretty unlikely. If they are dry as well then you should be good. I assume you mean Shift Sensor as one of the cables you have capped? Not break.
Another thing to try is unplugging the break cables as they are not necessary for operation and do stop the motor.
I think you'll probably need to wait for the multimeter
 

Gionnirocket

Well-Known Member
Region
USA
City
Y. O.
I don't actually use the Bafang brakes, never hooked them up.
Well all_righty then.

I assume that the XT60 and the battery discharge port/mounting bracket connector look nice and shiny at the connection points?
 

m@Robertson

Well-Known Member
Region
USA
Looks like the culprit is the wiring job, but some observations on your settings screen:

Low battery protection looks REALLY low. 0% on a 48v battery is 39.0v (3.0v per cell). You want your protection set up to be about ... 40v? Leave yourself some wiggle room. I realize the BMS should save it, but its better to have the controller do the shutoff at a slightly higher voltage level and then the BMS is a second layer fail-safe backup. Plus if the controller shuts the bike down vs. the BMS, you can bring the bike back to life after your voltage sag comes back. Maybe try and keep riding a bit longer on light PAS. A BMS shutoff is adios until you can plug into a charger.

17" wheels? Your pics show what looks to be at least a 26" bike. the setting is not critical to anything just an observation.

Current limit of 18a is quite conservative on a motor (BBSHD) that is typically good for 30a, with 25a being the typical lowball value. So long as that is deliberate no problem.
 

Gionnirocket

Well-Known Member
Region
USA
City
Y. O.
Looks like the culprit is the wiring job, but some observations on your settings screen:

Low battery protection looks REALLY low. 0% on a 48v battery is 39.0v (3.0v per cell). You want your protection set up to be about ... 40v? Leave yourself some wiggle room. I realize the BMS should save it, but its better to have the controller do the shutoff at a slightly higher voltage level and then the BMS is a second layer fail-safe backup. Plus if the controller shuts the bike down vs. the BMS, you can bring the bike back to life after your voltage sag comes back. Maybe try and keep riding a bit longer on light PAS. A BMS shutoff is adios until you can plug into a charger.

17" wheels? Your pics show what looks to be at least a 26" bike. the setting is not critical to anything just an observation.

Current limit of 18a is quite conservative on a motor (BBSHD) that is typically good for 30a, with 25a being the typical lowball value. So long as that is deliberate no problem.
I think that is the default page that loads with the program as I don't see a file name