cycle analyst troubleshooting - 12v output and pedal assist

[mcheck]

So I had a shop install a cycle analyst, Infineon controller, and cycle analyst on my bike after the original controller died (another long story which resulted in the shop also installing some torque arms). The bike is a custom setup with a 48V LI battery and 8FUN motor, and otherwise what appear to be generic parts.

When they gave it to me, all was working (although the pedal assist was lurching since it wasn't dialed in quite right), and then after one or two rides both the pedal assist and the cycle luminator both stopped working. Thankfully the twist throttle still works (and the auto cruise function is great).

To start simple, I decided to troubleshoot the cycle luminator first. The cycle luminator is hooked up to what appears to be the power output of the cycle analyst. The odd thing is that when I'm riding down bumpy hills, the light flickers on every once in a while. I followed the wiring harness back to the cycle analyst, and found that it wasn't generating any voltage from the power output. I opened up the cycle analyst and traced the wires back to where they hook up to the board, and there is no voltage even right where the wires attach to the board:

Any thoughts/tips on how to troubleshoot? Is this a fault with the cycle analyst, did I accidentally turn off the mainboard, or is it possible something somewhere along the line is shorting?

 

[amberwolf]

If the CA is working, then the input to it (VBAT) is working. AFAIK the lumenator output on the CA is from VBAT, so if there is no voltage on the output connector, there is a problem somewhere inside the CA's PCB.

Try measuring at the VBAT input on the CA itself, and compare that to the lumenator output, including measuring continuity on both ground and power with power disconnected from the CA.


If the pedal assist is using the THUN sensor, then that is also powered via the CA, but from low voltage, and the problem then is likely to be at the point where the THUN's power is derived from VBAT, I'd guess.

If PA is not using the THUN, then it depends on the kind of sensor and where it's power comes from as to where it might be.


I suppose it is also possible that there is a short in the wiring somewhere between the PA sensor and the lumenator's power, and that's causing both problems, but I'd guess that's unlikely if the CA is sitll working--I'd expect the CA to be damaged by any short like that.

 

[mcheck]

Good advice. I did the measurements and came up with some interesting results:

Vin is 54V (seems normal for a fully charged 48v battery)

The voltage for the luminator output behaves very oddly. If I disconnect all wires (unplug the harness) I get 0V. If I plug the luminator in, I get 30V.

Then I tested continuity between Vin (battery) and Vout (luminator) at the circuit board, as well as the respective grounds. The High voltage connections have no resistance as expected. The Grounds have infinite resistance.

I guess the problem is that the Voutput ground is ... ungrounded?

Is the fix here as simple as connecting the grounds together? Is the problem a bad PCB? I should be able to warranty the cycle analyst (It is < 2 months old) if needed.

Thanks!
-Martin