60V GNG troubleshoot question

[donny67ss]

Hi guys I finally got my bike back up and running after a bad accident. I had a bad AC joint separation and it took me down for about 9 weeks now, I was hit by a car on my way to work Long story short I have a 60V GNG on an Iron Horse SGS with 18s Lipo. Today I installed some Magura brakes and went out to test them and no more than a few minutes in the motor suddenly stopped. The lipos are on a fresh charge and I started to try and troubleshoot the issue. I already removed most of the hanky connectors (stupid yellow box) and soldiered everything up, so its not a wiring issue. I tested with my multi-meter (wires out the back of the stock GNG controller) I have power to the throttle (3.0v) and have power (2.7v) at the small blue, yellow, red, green, & black wires (sorry I'm not sure what the terms are for the wires ? ). Then I have no power at the larger Blue, Yellow, Green wires (what I think are the phase wires ?). I'm not sure how to properly troubleshoot this any help would be really appreciated. Thank you guys and happy almost 4 of July !!
Donny H
EDIT - I was incorrect about the voltage on the throttle wires red has 5.0V and the green and black have nothing.

 

[Electric Junk]

Hello fellow SGS rider, how did you mount the gng on the 100mm bb?

 

[donny67ss]

I used the stock mount and a rubber mallet My dad always said "get a bigger hammer"

 

[donny67ss]

I took apart the controller and everything looks fine nothing is burnt and the caps look fine. I have 73V into the controller. The small motor wires have power but nothing at the larger blue, yellow, green motor wires. It was running perfect for about a week and a half and then just no power. I'm not sure what my next step should be, or how to test the throttle. Donny H.

 

[Whitehawk]

If you don't have another controller to test the motor, try to test the mosfets of your controller maybe? See with a multimeter if there is a short between the legs 1/2 and 2/3 of each mosfet

 

[Lebowski]

shouldn't the throttle and hall supply voltage be around 5V instead of 3V ?

 

[donny67ss]

Hi Whitehawk thank you for the help! I tested the mosfets and I have 72V at three of them, i'm not sure if this is normal I don't know a whole lot about these controllers. Thank you again for your help. Donny H.

Hi Lebowski That's just what my cheap multi-meter is reading, I'm really not sure what the correct voltage should be at the throttle. I wish I knew how to test the throttle, I feel like a dummy that I cant troubleshoot the issue. Thank you for your help! Donny H

My Fiancee keeps yelling at me saying no more bike parts you dummy, you better fix it or your walking LOL O to be in love Donny H

 

[Whitehawk]

For the mosfets test : don't plug the battery !

My controller stoped working 2 times, I found 2 dead mosfets each time with this method, changed them and my controller work again

 

[donny67ss]

I tested them the correct way Thank you whitehawk. All nine mosfets are good according to the meter.

 

[donny67ss]

Ya Ya Ya!! I got it it was a short in the small wires from the controller to the motor, the Blue and red wires had a small cut in them. (I feel like a big dum dum I should have notice this sooner, live and learn) I cut out the bad wiring then re-soldiered and all is good i'm a happy camper now. Thanks for the help Whitehawk!! I just installed new Magura brakes and a new ISIS crank with a heavy-duty freewheel. Little more cleaning up and i'm ready to ride, which is good since this is my commuter to work everyday