Faulty DP C18 broke one BBS02B controller and two throttles

[Kanalj]

Had a bit of a tumble with my E-bike and the cable for the DP C18 display was tore and it cut some leads, thought it would be an easy fix; just solder back the leads. Boy was I wrong.

The leads must have shorted against each other and now my BBS02B is completely dead, wont turn on at all.
- I tested another cable harness
- I disassembled the engine and checked the connections

Thing is I tested it with my mates 850C display and it was still dead, so I tested my DP C18 with my mates bike (also BBS02B) and it turned on, but now he's throttle is dead and his speed sensor is completely dead (no light when it passes) (Error: 21H).

So my faulty DP C18 has probably shorted out both our controllers for our BBS02B's, I'm at a loss as what to do.

Only thing I can think of is updating to danielnilsson9 firmware and keep my fingers crossed it solves the problems for us both, just ordered the programming cable.

Anyone have any thoughts?
Probably have to buy 2 new BBS02B kits, feel like an asshole for bricking my mates bike..

 

[leffex]

You need two new controllers only if you are lucky and its no physical eletronic parts broken. Some of those can be changed and it would be advisable to try if you can a little DIY. But for my knowledge the screws may be butter. Use caution and 5-56 as we say to moisten it up.

To go the cheapy route may end up in a more expensive if it fails. There is a risk depending how you decide to go about it.

 

[Kanalj]

You need two new controllers only if you are lucky and its no physical eletronic parts broken. Some of those can be changed and it would be advisable to try if you can a little DIY. But for my knowledge the screws may be butter. Use caution and 5-56 as we say to moisten it up.

To go the cheapy route may end up in a more expensive if it fails. There is a risk depending how you decide to go about it.

Yea I've replaced a faulty controller before so no problems, just hoping it's a software issue and it's fixed with firmware.
I'm kinda new to the DIY scene here, have you heard other cases of shorted cables destroying the controller?

 

[fechter]

Absolutely, a damaged cable can blow the controller. One of the wires going to the display has full pack voltage on it. If this makes contact with any of the other wires, something will blow. You may need two controllers and a new display to fix everything.

 

[leffex]

Yea I've replaced a faulty controller before so no problems, just hoping it's a software issue and it's fixed with firmware.
I'm kinda new to the DIY scene here, have you heard other cases of shorted cables destroying the controller?

There are other motor brands using the same display sometimes and then they throw and error code like 30h or 21.They have one firmware per brand. Say Tongsheng and Bafang and they sharea few displays. I really don't put it to memory but the effect is then from a newly installed setup and not after a hickup like you described.

I think I have read you can start a bafang system connecting the correct wired but I'm not 100% sure and in this case you lose the lottery in this little accident of yours.

When you have nothing to lose you do some tests to get things going and the process towards the goal is in itself a reward also. But painfully costly sometimes. An accident can't always be predicted.

 

[Kanalj]

Ok sounds like I need a new controller for my mate, bought a new motor-kit for myself since that old kit was repaired previously (new hall sensors). Then I can play around with the old broken one, see if I get it up and running and give it to another mate (introducing new ppl to e-bikes is fun

Did not think those tiny cables from the display carried that much voltage though, like 5v max? But I'm no engineer.

I'll try to install danielnilsson9 firmware on the broken one the next weekend, I'll update here and see if I get a connection with the programming cable or if it's all fried. Interesting

Thanks for all the input!

 

[amberwolf]

Did not think those tiny cables from the display carried that much voltage though, like 5v max? But I'm no engineer

FWIW, it's a bad design for them to do what they do, but it is what we're stuck with, as nearly every controller/display setup of every brand, manufacturer, design, etc., uses the same method to switch power on. They did it this way because it's "easy" and cheap.


If it's helpful, there's info out there that shows what is on each pin of the BBSxx display/controller cable (and other connections), though it isn't all quite as straightforward as looking at the pictures--you may have to look up posts discussing the wiring as well, (some of the images in the search are from such pages; but there is a lot of such discussion here on ES if you poke around):

BBS02B display wiring - Google Search

The following doesn't make it clear, but "P" is battery voltage.


This one is slightly more clear by calling it "power", but it still doesn't say it's battery voltage (and doesn't clarify that the Lock wire is *also* battery voltage).


This page discusses some of the issues with wiring things up to the display connector for programming

Bafang Programming Adapter: More Cable Colors

It comes heartbreakingly close

softsolder.com

which includes comments on wire colors and voltages.

 

[Kanalj]

I'm at a loss, this does not make sense.

I just got the new controller mounted and I'm having the same exact issues: the throttle does not work, the speed-sensor does not work.

How? Could the electronics in the physical throttle be fried AND the speed-sensor?
I tried the throttle and sensor from both bikes, same thing.

The engine works, the pedal assist works.

Also: I'm getting a brand new Bafang kit on Monday and I'll test it with a new throttle and sensor, then we'll know for sure. Right now it's still a mystery, I'm leaning towards a curse atm. That or aliens.

Here's a video

https://imgur.com/HRJXHQs

 

[amberwolf]

If battery voltage shorted to 5v, either directly or thru serial-data electronics, it could have damaged or destroyed anything on the 5v line.

You can test the throttle itself with a 5v usb source to see if it provides the correct output range.

Same with speed sensor.

 

[fechter]

Sounds like you've replaced pretty much everything. It's possible there is damage to the 8-pin cable somewhere unless you've replaced that also. Basic inspection is to look carefully at the entire cable jacket for any signs of damage and unplug the ends and look at the connector pins to make sure none are bent/missing.

 

[Kanalj]

If battery voltage shorted to 5v, either directly or thru serial-data electronics, it could have damaged or destroyed anything on the 5v line.

You can test the throttle itself with a 5v usb source to see if it provides the correct output range.

Same with speed sensor.

Yea that seems to be the most logical conclusion and I'd like to test it but I have no clue how to use a multimeter, got one though. I'll try to figure it out, probably I'll test the speed-sensor since it got male connection (way easier than the female throttle), think I got the pins right but I'll do some more googling.

So: connect the USB power supply from + to 5vdc supply (red-wire) on sensor and from power supply - to Ground (black-wire) on sensor. Then multimeter red wire to the white-wire (signal-wire) on sensor and then the yellow from the multimeter goes to... ground on something?

Sounds like you've replaced pretty much everything. It's possible there is damage to the 8-pin cable somewhere unless you've replaced that also. Basic inspection is to look carefully at the entire cable jacket for any signs of damage and unplug the ends and look at the connector pins to make sure none are bent/missing.

I've checked with another cable, wiggled every pin.

 

[Kanalj]

Something like this?
Seems like it kinda works?

https://imgur.com/a/07ZEUmA

Oh yea, it lights up as well (constant light)

 

[fechter]

Sensor seems to be working. I think the controller has a resistor to pull up the output so it would read higher in actual use.

Something seems to be loading down the 5v supply.

 

[Kanalj]

Sensor seems to be working. I think the controller has a resistor to pull up the output so it would read higher in actual use.

Something seems to be loading down the 5v supply.

Has to be something in the engine-part and not the controller then, so the short-circuit blew something in the engine bit as well?

I measured the output from the speed sensor connector and it's 0.1 (seems low)

 

[Kanalj]

Sensor seems to be working. I think the controller has a resistor to pull up the output so it would read higher in actual use.

Something seems to be loading down the 5v supply.

I got the speed sensor to work!
I thought about what you said, something is loading down the 5v supply, and unplugged the throttle and tried it: now the speed sensor lights up when the magnet passes!

Yay!

 

[Kanalj]

Insides of a Bafang throttle, pretty basic. Probably a hall-sensor that's busted right?
Might have a spare one since I changed the ones inside the motor before.
Have a spare Honeywell SS41, anyone with know-how knows if this works?

 

[amberwolf]

SS41s are digital halls, and won't operate as a throttle.

SS49 are more like what you want, with an analog output; there will be a number on the sensor itself.

If you don't use the same sensor model the throttle will operate differently than it did before, maybe not by much, but response to the magnets will change.


Does the throttle output vary normally when used on the USB/5v supply to test it? If so, it's not likely to be causing the problem.

If it's not, then maybe the wiring harness of the new controller has a wire swapped to the throttle connector, shorting out the 5v supply.

 

[docw009]

Amberwolf is right. The 49E (or SS49E) was inside my Wuxing throttle.

 

[fechter]

OK, you're making progress now. I would just get a new throttle.

 

[Kanalj]

OK, you're making progress now. I would just get a new throttle.

Yea I got one ordered now, thanks for all the help!

The gist of this thread:
- Old controller and throttle from the bike I crashed is probably toast, but works fine with a new controller and throttle.
- Friends bike only had a toasted throttle that was giving the 5V-system a hard time, easy fix.

What I've learned:
- Never try to repair a broken bafang-display, buy a new one.
- Make sure the display-cables are not tangled up, so they can move freely when I crash.
- Put some vulcanasing tape around the display cables or harden them in some way.
- Throttles are sensitive things
- Bafang make good engines, but brittle (and stupid) electrical-systems.
- To use a Multimeter!
- You ppl rock!

 

[amberwolf]

Personally I'd add one more to the bullet list:
- Don't crash.




Regarding this point

- Bafang make good engines, but brittle (and stupid) electrical-systems.

that's true of *all* of the systems (that I have seen so far) that use displays, and even the Cycle Analyst, because they all have battery voltage in the same cables as low-voltage signals.

Any system that uses these "x-to-y" main harness cables has the same problem.

Even without the displays, the motor has battery (phase) voltage and low-voltage signals (halls, etc) in the same cable, on all hubmotor systems that are not sensorless, so any motor cable damage can do the same thing a display cable failure can do.


So, if you want to make your system proof against these failures, redesign and rewire all of the bike's cabling to completely separate your battery voltage and low voltage systems. You'd need to start from the inside of each device, at the circuit board, with separate cables that exit from separate ports in the casing, don't run next to each other to their destinations, and enter at separate casing ports on the destination.

It won't fix things like water-intrusion failures that can short things out internally to the devices, but it will prevent the kind of thing that happened here.