Need a new controller
- Thread starter grumpyG
- Start date
The LED 880 control panel works independently from the controller, so if it doesn't switch on, it's not normally a controller problem.
There are normally 5 wires to it:
Red and black are branches off the main battery wires that provide power for it.
Blue is a switched wire. When the panel is switched on, it connects red to blue so that the blue has battery voltage that goes back to the controller to power it.
The other two wires carry data Tx and Rx.
If the panel doesn't switch on, it's not getting voltage from the battery. If it flashes on, then goes off immediately, there's a short somewhere.
The battery wires go direct to the motor, but are blocked by the mosfets, which are under the control of the controller. If a mosfet blows, it can be a dead short, so the battery switches of any time it's connected.
First, you need to find out why the panel is getting no voltage? Did you measure the battery voltage coming into the controller before and after connection?
There are normally 5 wires to it:
Red and black are branches off the main battery wires that provide power for it.
Blue is a switched wire. When the panel is switched on, it connects red to blue so that the blue has battery voltage that goes back to the controller to power it.
The other two wires carry data Tx and Rx.
If the panel doesn't switch on, it's not getting voltage from the battery. If it flashes on, then goes off immediately, there's a short somewhere.
The battery wires go direct to the motor, but are blocked by the mosfets, which are under the control of the controller. If a mosfet blows, it can be a dead short, so the battery switches of any time it's connected.
First, you need to find out why the panel is getting no voltage? Did you measure the battery voltage coming into the controller before and after connection?
11.7 V is not the actual battery voltage. Your BMS has switched off for whatever reason. What you're measuring is just some charge bleeding through the MOSFETs. Is that measurement when connected to the controller? If it is, there's possibly a short in the controller. You have to disconnect the battery and measure again.
No straight from the battery terminals when not connected.
Thanks for this! I'm a bike mechanic with just a bit of electrical knowledge...
The only way to find out what's wrong with the battery is to open it up and meassure the cell voltages. If it's old, it probably needs replacing.
There will be a multi-pin connector on the BMS PCB that has all the cell voltage wires. You can measure the cell voltages there rather than strip everything down. You might have to peel off a bit of covering to get to the BMS. You put one probe on the ground where the cell-pack wire or strip attaches to the BMS, then test each pin. The voltage goes up cumulatively. Show photos if you can.
Great thanks. I did a video to show them but it wrong format for here. Going across the white connector in the photo I get about 3.4v per output (total about 36v) if I measure from charge port negative but it's all much lower from main battery negative ... If it was a simple thing I'd suggest an earthing issue but I dunno?
The charge indicator LEDs show the real state of the battery by the look of it and the charger 'says' it's charged. Feel like there may be a dry joint or a disconnect somewhere. What do you suggest?
T
hanks again
A component on the BMS board has failed , one is best to save messing about by replacing the BMS board. I have had similar with my diy bottle battery using crappy DALY BMS , two went wrong within six months.
The fault likely lies with one of those legged mosfets.
One could try re-wetting the main solder joints under the silicone to the BMS but unlikely to be the issue.
The fault likely lies with one of those legged mosfets.
One could try re-wetting the main solder joints under the silicone to the BMS but unlikely to be the issue.
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Ok...
4.1
8.2
12.3
16.5
20.6
24.7
28.8
32.9
37
41.1
Meter from B- to +ve battery output = 41.1v
Meter from battery o/p -ve to battery o/p = 12.2v
Sorry read that and last sentence is wrong - battery o/p -ve to battery o/p +be. You noticed my typo I'm sure but just to be clear...
Nothing wrong with the cell-pack then. So far so good.
Replacing the BMS is quite a big job, so I'd want to test a couple of things first.
Looking at the white multi-pin connector in your photo, starting from the left, the wires are red white and blue. Come forward from the blue wire and you'll see a little black resistor marked 102 sitting diagonally instead of in its correct position. See if you can tease it back into place with a soldering iron and some flux. The flux will help a lot. Then see if it comes to life.
Can you tell me where those 6 red wires on the left connector go? They're unusual, and not on a normal BMS.
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Hi. Sorry it's been so long. Been at work for a few days. I last used my soldering iron at work (repairing crap wiring on a Halfords E bike) and now can't find the thing. I bought a new one yesterday... And YES! I saw the twisted resistor and turned it as best I could and added some fluxed solder. Now charge level lights don't work and still have only 12v at the o/p. Suspect I've butchered the tiny resistor.
Shame I can't just connect the two grounds together to get the 41v at the o/p.....
Think it's time to give up and fit a new BMS? I can't find the same one online of course and I'm guessing the white connector and it's orientation isn't the same on all of them?
I'm tempted to buy a new battery and carrier from Yose Power - it'll be about £200 though and I'd enjoy the challenge of fitting a new BMS...
Thanks again!
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