Charging issue

[jimg]

I tried that exact search before posting. Most of the hits are the car itself or a parts diagram.

What I want to know is what does the grey wire do to control the charge? Specific voltages.

[Sergio]

How much voltage You are going to measure on the Gray wire will depend on the Impedance of your meter, do You know what that is?

The OBC floats the gray wire in a high impedance state.

When you plug the charger DC socket to the cart, current flows from the positive pin through the charger relay coil and into the Gray wire.

The OBC "senses" the pack voltage through the relay coil but due to its high impedance not enough current flows for the relay to activate.

After few seconds an internal FET in the OBC completes the Gray connection to negative and the charger relay activates.

If You have a cheap meter with an input impedance of around 6kΩ, the OBC may sense it as the relay coil (which is around 3kΩ) and complete the connection to negative and You will get pack voltage.

If You have a fluke or other high impedance meter, You will read around 42v depending on the exact impedance of the meter causing a voltage drop.

The red wire across the relay coil has a diode that needs to be in the proper orientation.

You did not mention what charger you have, this is the diagram for a PowerDrive 2:

[Fairtax4me]

All normal voltages.
The black and grey go to the OBC in the cart (On-Board charge Computer). The OBC keeps a reference on the black and grey wires as a sense voltage to know when the charger is plugged in.
After detecting the charge is plugged in the OBC closes the grey wire connection to pack negative which activates the relay in the charger. Charger turns on. This detection is the 2-10 second delay.

The OBC may need to be reset. If it has commanded the charger on at some point but the charger did not turn on because it did not have AC power, or there was a connection problem between the OBC and charger, the OBC can go into a sleep ode or disable mode. You can try driving the cart a few feet. Pressing the throttle with Key On sends voltage to the OBC to tell it to Wake up.
The OBC can disable the cart through the charger interlock, so if the cart is disabled, disconnect the pack negative cable for 10-15 minutes to reset the OBC and it should then wake up on re-connection of the pack, and should then allow the charger to turn on.

[R&TBabich]

Originally Posted by Fairtax4me

.... The black and grey go to the OBC in the cart. The OBC keeps a reference on the black and grey wires as a sense voltage to know when the charger is plugged in.
After detecting the charger is plugged in the OBC closes the grey wire connection to pack negative which activates the relay in the charger. ....

Say the OBC has been completely removed and a smart charger (Modz Max) is connected to the stock plug-in port.
Can the gray wire be used to trigger a NC relay to break the White/Lt Blue to disable the controller?
Or is there another way?

[jimg]

I'm using a 10Mohm meter.

That's the correct schematic - thank you.

Any explanation of why my black connector lead is so far from 0v?

I'll try resetting the OBC later today when I've dealt with the honeydos.

[jimg]

My cart moves okay, but I did the OBC reset just in case I misunderstood. No change - grey wire not closing to ground...I guess I have to clean out enough space in the garage to get the cart to where I can work on it...

No one has an OBC schematic, by any chance?

[jimg]

So I opened the inline fuse and grounded the charger plug pin, and the charger fired right up. At least I know that's not the issue, and can put that back together. Now to figure out how to fix the OBC or if I'm lucky, the wiring...

[Fairtax4me]

Originally Posted by jimg

I'm using a 10Mohm meter.

That's the correct schematic - thank you.

Any explanation of why my black connector lead is so far from 0v?

I'll try resetting the OBC later today when I've dealt with the honeydos.

If resetting the OBC does not get it to work then the OBC has failed and needs to be replaced or removed.

The black lead goes to the OBC and goes through the SCR circuits in the OBC to control charge amperage output. The FETs used in the SCR have a high resistance when the OBC is off, so you will not read true pack voltage using the black wire.
Schematics are not readily available for the OBC. It’s a sealed unit so the internals are not accessible for repairs. Really if it fails the best option is to remove it and buy a smart charger.

[Fairtax4me]

Originally Posted by R&TBabich

Say the OBC has been completely removed and a smart charger (Modz Max) is connected to the stock plug-in port.
Can the gray wire be used to trigger a NC relay to break the White/Lt Blue to disable the controller?
Or is there another way?

With a Modz Max Charger no. As far as I know the Modz max does not have a third wire hookup to use as an interlock control. This one would need a relay activated by the main charge leads.

The Lester Summit II can use the grey wire for interlock control.

[jimg]

Can someone educate me on replacing the OBC with a "smart charger". Brands, features, swapout, etc? I haven't given up on bad wiring, but haven't had time to look yet.