Will a bad resistor make my cart quit?

[imarealgolfr]

http://www.buggiesgonewild.com/image...attach/jpg.gif
OK here is a picture of my controller

[cgtech]

Sorry, but why do you have huge cables installed on that puny stock controller? Its not gonna make that thing any better. Sorry this post is not so helpful, but i think you might be building in the wrong direction (a bomb shelter around a doghouse).

[imarealgolfr]

Sorry cgtech, I didn't know I shouldn't have upgraded my cabled before I upgraded my controller. But all that behind us, I don't think that is not why it isn't running, since it was running fine

[JohnnieB]

Originally Posted by imarealgolfr

1. Ok I can't seem to get a pic of my controller to upload, but it only has three terminals. M- on the right,B- to the left and B+ to the left of that.

2. My black test probe on m- and red one on b+ I got nothing.

3. With black probe on m- and red probe on b- it reads -27.2 (which is what I get on the controller side of the solenoid) and when I press on the pedal it goes up to -38 volts. Now when I switch them to red on m- and black on b- it reads positive volts. I'm confused

1. Got it. We're on same page about which terminal is which.

2. Should be Zero volts when the solenoid clicks and should climb to 38V (or whatever the pack voltage is at the time) when the pedal is pushed to floor.

Not climbing up from 0V could be due to an open anywhere in the high current circuit as well as a bad controller or throttle.

3. B- is the most negative point, so if the negative test lead (Black) is connected to it, the voltage on the meter will be positive. If the Red lead is on it, the voltage will negative. In either case the is the difference in the electrical potential between the two terminals, so the polarity sign on the voltmeter readout is incidental.

The voltage before the solenoid clicks is also incidental. After the solenoid clicks, you should get pack voltage (38V?) between B- and M-. Then when pedal is pushed to the floor, it should decrease to zero.

If it doesn't, either the controller is bad, or the throttle signal to the controller is bad.

[imarealgolfr]

Every thing else checked out good (as far as the other tests). So I'm thinking a bad controller. Is that what you are thinking JohnnieB?

[JohnnieB]

Originally Posted by imarealgolfr

Every thing else checked out good (as far as the other tests). So I'm thinking a bad controller. Is that what you are thinking JohnnieB?

Either a bad controller or a bad throttle signal.

Check the throttle input to the controller.
Voltage on Pin-1 (white wire) should be 0.4V to 0.6V when pedal is pushed just far enough for solenoid to click and should be 1.5V to 1.7V with pedal pushed all the way to the floor.

If you get those voltages, the throttle is good and the controller is bad.

[imarealgolfr]

I believe that's what I got the other night,I'm pretty sure i eliminated the throttle,but I will check again this evening. Sounds like I'll be getting a hold of Scotty

[imarealgolfr]

OK JohnnieB
This is what I got checking this evening
White wire
solenoid clicks I get 0.5 volts
slowly depressing the pedal it moves up to 1.7 volts
Throttle is good?
Red wire to controller=pack voltage ?
Black wire to controller 14.3 volts ?


Then I did a little more probing
- lead on - on battery to b+ terminal= pack voltage ?

Battery side of solenoid= pack voltage
Now on the controller side it is 27.5 and the trouble shooting sheet says it should be within 3 volts of pack voltage, which now is 37.9. I am wondering why that is so much different. And that is what b- and m- starts out at and goes up to pack voltage when the pedal is pressed, and it is spose to be going the other way that is why I am confused.

Any how,thank you JohnnieB for helping me figure this out,it is GREAATLY appreciated. I am a carpenter, so I know just enough about electricity to get me in trouble

[JohnnieB]

Throttle signal is good.
Red wire voltage is good. (This is what tells the controller to turn on)
Black wire is good (This is the voltage source for the throttle signal)

B- on battery pack to B+ terminal on controller is good.

The 3V drop mentioned in the troubleshooting tree is very approximate and assumes the controller is good. There is a 250Ω resistor connected between the solenoid's two large terminals to keep the filter capacitors inside the controller charged so the solenoid contact don't arc as much when they close. The current flow needed to keep the capacitors charge typically drops about 3V across that resistor, the the voltage on the controller side terminal typically reads about 3V less than battery side terminal. If the controller's innards are drawing more current than normal, the voltage drop will be greater.

The voltage between M- and B- will be pack voltage less the voltage drop across the resistor before the solenoid contacts close and then jump to full pack voltage when the contacts close and before the throttle signal tells the controller to pass amps to the motor. Once the throttle signal starts telling the controller top pas amps to the motor and the controller does what it is being told to do, the voltage between M- and B- will decrease as the throttle signal increases until the controller is passing all available amps to the motor and at that point the voltage drop between M- and B- will be zero or very close to it.

Since the controller isn't doing what it is being told to do by the throttle signal, the voltage jumps to full pack voltage when the solenoid's contacts close and stays at that voltage no matter what the throttle signal is telling it to do.