Is my controller faulty??
- Thread starter Smart
- Start date
Jeremy Harris
100 MW
Smart said:
This pretty much confirms that the battery has a problem, either with some cells having failed or maybe with the BMS. It may well be possible to fix it though, so there's nothing really to be lost by taking it apart and trying to find the exact cause of the problem. You may not need to get a new battery from the original manufacturer/dealer, as it may be possible to replace the cells with others that will work OK. It all depends on what's inside the blue heatshrink plastic wrapper.
Jeremy Harris
100 MW
That's pretty good news, as it looks as if the cells may well be OK, which means the problem is elsewhere, either with the BMS or perhaps a dodgy connection/switch.
Could you take some more photos of the internals of the battery? There should be a BMS circuit board in there somewhere, probably wired to the row of small connectors to the left centre of the main cell connections.
Could you take some more photos of the internals of the battery? There should be a BMS circuit board in there somewhere, probably wired to the row of small connectors to the left centre of the main cell connections.
dnmun
1 PW
that is way cool efficient use of space. there is a screw in the corner on top that the red battery plus wire come off of?
while that is disconnected from the battery you can check the resistance over to the controller red wire to see if there is a flakey switch or damaged connector but you don't have to take the BMS apart more. it has some white goop on it that sticks the heat sink plate on top to the transistors.
if you can reach the BMS with your voltmeter while the battery is plugged into the frame then you can check the voltages when you spin the wheel. if not you can test the battery by discharging it into a space heater. you can measure the voltages on the pins on the side of the BMS where they plug into the top of that pcb. was that plug tight when you pulled it out?
while that is disconnected from the battery you can check the resistance over to the controller red wire to see if there is a flakey switch or damaged connector but you don't have to take the BMS apart more. it has some white goop on it that sticks the heat sink plate on top to the transistors.
if you can reach the BMS with your voltmeter while the battery is plugged into the frame then you can check the voltages when you spin the wheel. if not you can test the battery by discharging it into a space heater. you can measure the voltages on the pins on the side of the BMS where they plug into the top of that pcb. was that plug tight when you pulled it out?
there is a screw there but the red plus is not coming off of it, unless there is a run on the pcb that I cant see due to the putty like substance they have glooped on it. but as you can see in the image a tiny part of the red plus is exposeddnmun said:
not sure what you mean by this. Do you want me to check the red live on the controller?dnmun said:
The plug was seated tightly and took some effort to get it off.dnmun said:
I've just put the bms back together with the battery, I have not put it back in its housing so I can still check the voltage across the cells using the screw holes
They are still reachable with the bms on top.
They give me a reading of 41.7v all the time.
Now on the other hand the the positive and negative that are coming from the BMS only give a reading of 41.4v when not connected to the controller,
when they are connected to the controller they give an inconsistent reading of around 30v and gradually builds slowly by about 0.1v every few seconds.
Does this mean the BMS is getting confused?
They are still reachable with the bms on top.
They give me a reading of 41.7v all the time.
Now on the other hand the the positive and negative that are coming from the BMS only give a reading of 41.4v when not connected to the controller,
when they are connected to the controller they give an inconsistent reading of around 30v and gradually builds slowly by about 0.1v every few seconds.
Does this mean the BMS is getting confused?
Jeremy Harris
100 MW
Sounds very much as if the BMS is faulty and is partially shutting off. It has an electronic power switch internally that is supposed to turn off the power when either too high a current is drawn or if any cells in the battery pack discharge to too low a level. This should be a hard switch, that turns either on or off, but in your case it seems that the BMS is presenting a high resistance path, hence the varying voltage (which is just the capacitors in the controller charging up slowly).
The hard part is deciding what to do now. The BMS isn't one I recognise (someone else here might, though) and guiding you through diagnosing and repairing the BMS isn't going to be that easy. It might be worth starting a new thread with BMS in the title, together with some photos of it, in the hope that someone else on here recognises the type and either knows how to repair it or where to get a replacement.
The hard part is deciding what to do now. The BMS isn't one I recognise (someone else here might, though) and guiding you through diagnosing and repairing the BMS isn't going to be that easy. It might be worth starting a new thread with BMS in the title, together with some photos of it, in the hope that someone else on here recognises the type and either knows how to repair it or where to get a replacement.
