PanlongIC Controller Troubleshooting

alexose

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Jul 23, 2018
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Hey everyone,

First off, I wanted to give everyone here a thank you for participating in these forums. It's been such a helpful resource as I tinker on my various contraptions :)

My issue is that I'm midway through swapping a controller on a old/broken ebike I got for cheap. It's a very standard 36V/500W in-hub setup, so I picked up one of these guys: https://www.ebay.com/itm/182583980617

I connected up the the battery, lock/ignition, hall effect, motor, and throttle wires. Plugged in the battery, and: Nada. No movement at all. Just to test, I connected up the self-learning wires and turned the throttle. No movement, no nothin'. No matter what, I can't get the motor to budge. And, I know the motor is good, because it was working somewhat with the last controller.

Figuring I had the throttle hooked up wrong, I tested the voltage across all of the wires that are meant to hook up to the throttle and LED display. Based on my (admittedly limited) knowledge of throttles, I would have expected to find a 4.2v signal, but I didn't-- I could only find a 0.8v signal. The signal is very steady, though, so I don't suspect component failure.

Here's where I'm stuck: I don't know where to go from here. Test more wires? Buy a new controller? If anyone here has experience with troubleshooting controllers, I would love some ideas!
 
0.8v is what you get on a hall based throttle when the throttle is at zero. It'll be around 4v or so when it's at full throttle. If the voltage changes as you turn the throttle, it's probably working fine.

If it doesn't change, it usually means either something is wrong inside the throttle (not likely since it worked before) or something is wired wrong and it's shorting the signal to almost-ground. If you had to experiment with wiring, and the battery voltage to the LEDs ever got hooked to either throttle 5v or throttle signal, then it would have damaged the hall sensor, and that would have to be replaced. (new throttle is easier).

There should be about 5v or so on one of the throttle connector wires, as power to the throttle; if you don't have that and throttle isn't working you'd have to find out why ther'es no power.

The most common reason for no power to throttle (or motor halls) is the "keyswitch" or "ignition" or "lock" wire on the controller not being hooked up to battery positive.
 
The lock wire is connected properly (I triple-checked-- When I disconnect it, the whole controller turns off. Like, 0 volts).

My working theory is that maybe one of the hall wires was mislabeled. The current order of business is to hunt around for that 4.2v signal, I think. Will report back soon with findings.

Another surprising thing is that I'd expect there to be a ~36v signal coming from the 'Instrument Panel' wire. 0.8v there as well.
 
alexose said:
Another surprising thing is that I'd expect there to be a ~36v signal coming from the 'Instrument Panel' wire. 0.8v there as well.
Depends on what that signal is for. If it's for a speedo, it's probably just a repeater of one of the motor hall signals. If it's for a battery voltage meter, then it would have battery voltage on it--but that kind of signal is already covered in the throttle connector via the LED power wire, usually.
 
I went ahead and tested the rest of the wires. Voltages were all over the place, but all below 1.1. No 36v signal to speak of. Flummoxed, I figured I'd open up the case and see if there was something wrong with the board:

IMG_8948.JPG

Now, I'm no expert, but that doesn't seem right :)

Ordering another controller. I'll post back here when I get it hooked up.
 
If you mean the glue, that's normal. Without it, the capacitors would vibrate around and break off of the board or their legs, and stop doing their job.

But if you're not getting battery voltage at any wire in the controller, there's somethign wrong with the power wires leading up to it.

Or somethign wrong with the voltmeter being used to test it, like a low or dead battery (which can cause wierd readigns), or being used on the wrong setting (AC vs DC, etc).


There should be power on at least two wires, the main battery wire (probably taht thickest red one) and the keyswitch/ignition wire (probably that thin one coming off the bottom left area).

Whehter there is battery voltage on any othe rwire depends on how the controller is designed inside, and what wires are soldered where. Some controllers don't have a pad on the board to pass battery voltage thru, and isntead a wire gets spliced into the keyswitch/ignition line to run up to any pwoer meter,
 
Ah, glue. I thought maybe it was a burst capacitor or something.

The voltmeter is working properly.. I'm getting a solid 36v from the battery, and from the end of the cord where the battery reaches the controller. The cord is fine, too-- I measured the resistance and got very low values for both positive and negative.

The strange thing is that when everything is plugged in, and the battery is hooked up, and I've double-checked everything, I'm *still* measuring a very low voltage between the positive and the negative terminals on the controller board. I have no idea how this is happening-- It's almost like the BMS is stepping in and turning everything off.

Given that I was able to use this battery successfully in the past, I have to conclude that it's the controller.
 
alexose said:
Ah, glue. I thought maybe it was a burst capacitor or something.
Those are usually messier; the stuff tends to look like a thin liquid mixed with paper towel fuzz, and sometimes metal foil bits.


The voltmeter is working properly.. I'm getting a solid 36v from the battery, and from the end of the cord where the battery reaches the controller. The cord is fine, too-- I measured the resistance and got very low values for both positive and negative.

The strange thing is that when everything is plugged in, and the battery is hooked up, and I've double-checked everything, I'm *still* measuring a very low voltage between the positive and the negative terminals on the controller board. I have no idea how this is happening-- It's almost like the BMS is stepping in and turning everything off.

Ah--that is a different way of saying it that says a lot: The BMS almost certainly *is* shutting down to protect teh battery from something.

It could be doing it because of overcurrent (a short circuit in the controller, which could be a miswiring like reversed power, or a failed capacitor or FET, etc), or it could be that the battery is actually not fully charged, or badly imbalanced.

It's unlikely in a low-power controller, but the overcurrent / short could even just be that the caps are so large in the controller that they need a precharge resistor at first hookup, so that the battery doesn't have to supply so much current so fast that the BMS shutsdown because of it.


It's more likely to be a controller issue, but the battery can be checked by leaving it on the charger at least overnight, or longer, watching it to see if it turns on and off and on and off, which it typically wlll do as the BMS shuts charge on and off to do balancing. Or you can meausre individual cells to verify they're all the same voltage.
 
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