BBS02 fried after plugging in C961 display? Need help diagnosing

[hhhapz]

Hey folks, I converted my bike with a mid-drive setup with a 750w 48V BBS02. Initially I ran it without a display, since I wasn't happy with the options available on that listing, and I just rode with a USB<>UART cable and configured it via bdac. Set up PAS, throttle behavior, wheel diameter, etc. Worked fine for a few rides on my first day of getting everything setup. The one thing I should note is that I was using a 52V 15Ah battery, however I never ran into any issues while riding.

I ordered a C961 display off Amazon, unplugged my serial adapter and swapped in the display. I powered it on (held power button ~2s), screen came on but it wouldn't stay on and turned off itself. I immediately smelled burnt plastic (like the "magic smoke of death" smell). I however didn’t see anything visibly fry, and I was in the parking lot, so maybe it wasn’t even my bike (however I am relatively certain, given the timing). Still, I disconnected and reconnected my battery and the battery.

And... now everything’s dead. When I used to plug in the serial cable and switch on the battery, a blue LED on the cable would light up, but now it doesn’t (unless I plug in the USB part into my laptop). Even with the C961 connected, holding the power button does nothing.

I was hoping maybe the smell was unrelated, but seems unlikely now. What are the odds that plugging in the C961 actually fried the controller? That’s my current theory. I'm a bit hesitant to tear into the motor (cranks, pedals, etc.) unless I have to, so trying to figure out next steps. Any other potential causes? I'm incredibly torn after the amount of effort I've spent setting everything up on the bike to get to this point.

Appreciate any help.

 

[amberwolf]

The display / controller connector for the average system contains B+, Ground from controller, keyswitch/Ignition KSI (which is B+ fed back to controller when you turn on the display), and TX/RX between the two.

Not all display/controllers are compatible with each other, and not all of them are wired the same.

If either your controller or your display uses a different wiring from the other, or you have an extension / etc cable between them that does, battery voltage via either B+ or KSI could have been connected to TX or RX and blown up either or both display and controller.

 

[hhhapz]

I see... ouch. How would I verify if the wiring pins likne up or not? I'm relatively certain the controller is gone, given that the usb serial cable is no longer powering on.

How difficult of a replacement job is this?

 

[amberwolf]

The BBSxx wiring / connector diagram is pretty well documented around the internet, including in various places here on ES; an image search for them should find it.

The display...it might depend on which controller/version it's for, or which seller it's from, but taht's a common display so it should also have typical connector diagrams out there.

Most of these are a 5-pin or 6-pin connector, whcih are hard to plug in wrong without noticiing it's offset or rotated because it crushes pins or bends them and feels wrong, but they're still round, so if it's done anyway, it might be possible to line up battery voltage with low voltage pins.

I haven't ever opened one of these up, but there are several BBSxx threads aroudn here discussing and probably showing this, either for upgrading or replacing the controller as a repair, etc.

 

[amberwolf]

BTW, if the display itself doesn't even power on with it's own button, but it did initially, maybe the controller is no longer supplying power to it. YOu can check for battery output at the controller's B+ input and at it's display connector B+ output, to be sure it wasn't the battery itself that popped something.

 

[docw009]

A BBS02B controller is selling for $127CDN on amazon.ca for prime day.

View of the male display connector coming out of the controller for your convenience. Power/ground (52V) across the brown/black. When display turns on, it puts 52V onto the orange pin. This is what the program cable does. It straps the brown and orange pins together.



Might as well see if you still have 52V across the above two power pins. If not, disconnect the battery and do continuity on the plus and negative lines. It's a straight shot from the battery connector to the power/ground on the connector.

You did buy a C961 display with a female connector, intended for the BBS02B. There are displays with male pins that have a different pin order. Sometimes people try to use these with gender swapping adapter cables, and who knows what could happen..

 

[E-HP]

I ordered a C961 display off Amazon, unplugged my serial adapter and swapped in the display. I powered it on (held power button ~2s), screen came on but it wouldn't stay on and turned off itself. I immediately smelled burnt plastic (like the "magic smoke of death" smell). I however didn’t see anything visibly fry, and I was in the parking lot, so maybe it wasn’t even my bike (however I am relatively certain, given the timing). Still, I disconnected and reconnected my battery and the battery.

I could return/exchange it since it’s Amazon, as a first step, before replacing the controller.

 

[hhhapz]

Thanks for all the suggestions everyone. I'll do some troubleshooting