36v series cart wont run.

[firefighter1868]

On thing to add. What should the amperage meter on the charger be reading. Mine is at 20 amps does that sound right. As the batteries charge the amps lower.

[Sir Nuke]

Originally Posted by firefighter1868

On thing to add. What should the amperage meter on the charger be reading. Mine is at 20 amps does that sound right. As the batteries charge the amps lower.

YES....that correct.

[mutant]

ocd is good practice for battery connections...you might have a great deal there!

[firefighter1868]

Thanks I'll give another update when I get out messing with it today. My oldest son try to move it after charging the battery and said it was making a clicking noise coming from under the box. I'll check all the voltage and let you guys know what the "clicking noise" is coming from. If I had to guess it would be the solenoid.

[scottyb]

If the solenoid is clicking then the the problem is in the control or high amperage delivery or motor.
Controller output can be tested with a handheld voltmeter between the B- and M- terminals. Watch the meter as your son slowly depresses the gas and holds it still just after the solenoid clicks. The reading should be the same as the battery pack voltage.
If yes, ask him to press the pedal down and the voltage reading should drop near 0 when the pedal reaches the floor.
If yes, the controller is working and the problem is likely in the cables or F&R.

[firefighter1868]

Well, with the - on M- and the positive on B- , key on and pedal pressed till solenoid come on I'm only reading about .4 volts. I don't see battery pack voltage anywhere. Also if I remember right, I read from B+ to M- should read zero, I'm reading battery voltage. All the test on the throttle sensor and switch came out right.

[JohnnieB]

Those two readings point to the MOSFETs in the controller being shorted, but if that was true the motor should be turning or something should be smoking.

I suspect the reading between M- and B+ is actually 0.4V less than full battery pack voltage and is due to a phantom current path coupled with a high impedance DVM, so let's disregard it for the time being.

Connect the Negative test lead to the controller's B- terminal and measure the voltage at the battery pack's main Positive terminal. Note that voltage.

Now connect the positive test lead to the controller's B+ terminal and you should read about 3V to 5V less the the noted voltage.

Press the pedal until solenoid clicks and the voltage should increase to the noted voltage.

Now turn key on and place F/R selector in F and move the positive test lead to the controller's M- terminal.

When the pedal is pushed just far enough to make solenoid click, you should read the noted voltage.

If not, use the positive test lead to check the voltage on the four studs on the F/R switch.
They should all four have the noted voltage on them.


The attached schematic shows the series current path from the battery pack's main positive terminal to the motor in RED and from the motor to the battery pack's main negative terminal in BLUE.

It is a single series path and if you don't get the noted voltage between B- and M- on the controller when solenoid first clicks, there is an open somewhere in that singles series path.

[firefighter1868]

I'll go check right now. That's exactly what I was thinking. I did notice yesterday that when trying to go in reverse its very hard to shift. May be in that but I've checked the switches with the ohm meter but they where good. But that doesn't mean I'm getting the voltage out when petal is pressed. Ill be right back. I'll note all my readings while I'm out there.

[firefighter1868]

38.73 from b- to +battery post. Now positive lead on b+ and negative lead on b- I'm reading 38.64. I'm not getting pack voltage at B- and M- with key on. I'm gonna go on with the diagram now.

[firefighter1868]

I think I'm on to something here. I'm getting voltage all the way until I get to the F/R switch. Its coming in on A and then leaves on D going to S2. Then it leaves S1 and comes back to B. That's where it stops. I'm not getting anything from B to C. Does this make since?