Help needed checking drive wheel

KERABO

1 mW
Joined
May 30, 2022
Messages
14
Hello
I am new to the group and quiet new to EBikes but have a little electrical knowledge from motor vehicle.

I purchased an Ebike cheap as a non runner. It’s wires to the drive we’re caught in the chain and even with them repaired it’s dead.

The charger charges the 36v battery to 42 volts and the charger terminals are live.
The output terminals at the bottom is dead on the Neg but live on the Pos
Following the wires they go to what I know know is the BMS. If I bridge them across I have power at the base terminal.

I am not sure what to do next. Tempted to join the terminals with a strong fuse ?

I read that they can be reset by removing the connectors but this don’t seem to have made any difference.

I hope you can see my pictures and the heavy black wires.

Thanks Ken
 

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With munched motor wires, it's likely the controller was destroyed (blown FETs, etc) from shorted phase/etc wires. This may then have caused the BMS to shutdown to prevent pack failure from overload due to internal short at the controller.


If the BMS is shutdown even when disconnected from the rest of the bike, including from the controller (that is probably inside the battery case), it's possible the FETs were actually damaged by the short.

If the controller is still connnected to the BMS/battery, you need to disconnect it to troubleshoot the battery and BMS.

First, check the cell voltages at the connector where all the wires go to the BMS. If all of them are about the same voltage, within 0.1v of each other, and all above 4v, when it's charged and not connected to anything, then the cells aren't the reason for the BMS to shut off.

If there's any cell that's low enough or high enough it could cuase the BMS to stay shut off.

If the FETs are blown, they often fail shorted, so it would be stuck on, and you'd see full voltage on the output--if they're blown open, there's often chunks of plastic missing, or obvious cracks and burn marks on the black plastic casings. I dont' see that, so they're probably ok (can't see all of them though).

Similarly, the large mustard-colored flat square is a protection, and could also fail open--but it would also likely fail catastrophically and obviously, so it's probably ok.

If the BMS just shutdown and the FETs are ok, then resetting the BMS may fix it. The pics of the BMS board dont' show enough of the board under the balancing board to see if it has a set of pads that can be shorted to reset it (some do, some don't). It might be visible/accessible from the back, or maybe only under the balancing board (which would be PITA to unsolder and remove, especially since you'd have to be very careful not to short any of the B(number) pins, since those go directly to each cell group and have battery voltages on them).

If there are no reset pads on the BMS, then you may be able to reset it by shorting momentarily from the actual battery negative wire (the fat black wire to the cells from the BMS B- terminal), to the P- / C- terminal on the BMS. (which is also what you would short across to bypass a dead BMS)

If it won't reset, and the cells are ok, you can replace the BMS; they're cheap enough these days, but you may not find one exactly like that one.



The controller for the motor (likely also inside the battery casing) probably has to be replaced from the motor short; you can test it's FETs at least without powering it up using the procedures at Learn - Troubleshooting section for controller testing at http://ebikes.ca .
 
Thank you for that detailed reply. I only just noticed it.

Would I be correct in that everything inside of the battery box is only to control the battery?

I fed 36v to the terminals where the battery connects and it all lights up. When I press go the wheel just gives a quick kick and then a warning showing an engine like on a car is on the display.

Thanks Ken
 
KERABO said:
Would I be correct in that everything inside of the battery box is only to control the battery?
Depends. There's a lot of bottle batteries that have the controller in it too. If there are only two wires going from battery to motor, then controller is inside the motor. If there are two wires that go from battery to some other box, then several wires to the motor, that box is the controller. If there are several wires going directly from battery to motor, then controller is one of the boards or devices inside the battery (the one the several wires come from).


I fed 36v to the terminals where the battery connects and it all lights up. When I press go the wheel just gives a quick kick and then a warning showing an engine like on a car is on the display.
That probably indicates that, as expected from a wire munching, the controller has been damaged (probably shorted FETs). The halls in the motor may also be damaged, if any of their wires got shorted to any of the motor phase wires (which carry much higher voltages than the halls are made to handle). There are testing procedures at http://ebikes.ca in the Learn - Troubleshooting section to see if either of these is the case.

It could just mean that there's still a connection problem, either something not connected that needs to be between motor and controller, or something that is connected incorrectly.
 
Yes the battery has 5 contacts but only 2 are live. The base it sits on seems to have the controller inside.
It’s a little deep for me to take in but I am learning.
Thanks Again
 
KERABO said:
The output terminals at the bottom is dead on the Neg but live on the Pos

What do you mean by dead on the Neg? Between what two points?

KERABO said:
I fed 36v to the terminals where the battery connects and it all lights up.

What did you use as your 36V source, assuming you mean you applied it to the controller battery inputs?
 
Because of the faults in the BMS the Neg main feed to the contacts at the bottom of the battery pack has no feed.
If I join the two thick black wires in the BMS it then feeds as it should but this must be bypassing the BMS
Thanks Ken
 
KERABO said:
Because of the faults in the BMS the Neg main feed to the contacts at the bottom of the battery pack has no feed.
If I join the two thick black wires in the BMS it then feeds as it should but this must be bypassing the BMS
Thanks Ken

Got it. So when bypassing the bms, providing 42V, the bike shows some signs of life, including a brief motor movement but doesn't spin. It's a good sign that the motor at least responded, and that the pack can be fully charged.

You could perform some tests without opening the motor to check the condition of the hall sensors (fried?) and phase wires (shorted?). If the motor checks out, then you're looking at repairing or replacing the controller, and replacing the bms.

If it were me, in sequence, I'd test the motor first. If halls are bad, I'd try to replace them. if the phases are shorted, i probably would give up. if the motor is good, i'd replace the controller (not worth the time or effort to diagnose or repair), bypass the bms, an get the bike running. if successful, then i'd replace the bms.
 
You have been very helpful

I will slowly work my way through it.

Thanks again Ken
 
Hello again

Could you please guide me a little more.

Just to test I have fitted 3 x 12v 10Ah batteries making 36v connected.

Again it just kicks the rear wheel and then stops but I notice code 07E and a motor flashing.

This resets every time I power off.

I looked this code up and it seems to suggest connection between controller and motor. As the wires had been damaged and a poor repair I cut out and rejoined with solder each wire and am now certain this is good.

I would be happy to buy a controller but the bike hardly worth buying a new wheel and motor.

I have a good multimeter but the wires and connectors are so small it would be difficult to test.

I see you can buy a test rig in eBay quiet cheap?

Any ideas please

Thanks Ken
 
Can someone tell me how I can test my 250w rear wheel please.

I have a quality test meter but the terminal plugs are very compact.

Do I have to dismantle to test the Hall Sensors?

Thanks
 
what's the problem with it ?.. running rough .. locked up... weird sounds... not powering up...
 
Thanks for the reply.
I bought the bike Greenedge CS2 cheap as the wires from the controller to the wheel had been in the chain. Repaired the wires but all the wheel does is sort of kick each time I power on and press go. Then error code 07E shows.
I bought a controller as not that expensive but it’s still the same but error code 01 from memory.

Someone said it’s most likely the Hall Sensors.

Saying that if my ECU needs setting to the bike I can’t get info on how to access the settings.

Thanks Ken
 
KERABO said:
Someone said it’s most likely the Hall Sensors.

Saying that if my ECU needs setting to the bike I can’t get info on how to access the settings.

Thanks Ken

If you want to help people to help you, keep all the info in one thread so it's easier for people to get the context, or at least link to your other thread so people can see what steps you've already taken to diagnose your issue, which has evolved as you've provided more clues.
https://endless-sphere.com/forums/viewtopic.php?f=49&t=116351
 
Sorry

I am struggling to find my way round the forum.

Unable to locate my last mails .

I have now learnt how to get a warning I have new mail,.

Ken
 
KERABO said:
Sorry

I am struggling to find my way round the forum.

Unable to locate my last mails .

I have now learnt how to get a warning I have new mail,.

Ken
It's not always intuitive, but if you click on your name in the upper right, below the search bar, it will allow you to see your profile. In that page, you can click on "Search user's posts" and that will show you every post you've ever made on the forum.
 
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