2002 Club car goes slow

darrellinceres

Hi, my name is Darrell and let me thank you in advance for taking the time to give help me on my newly designated job. I'm the head electrician at the plant I work for and one of our managers has decided that since it's an electric golf cart that I've been promoted, or demoted how ever you want to look at it, to golf cart repairman. I have an old EZGO electric flat bed utility cart at my ranch but this is a totally different animal.

It's a 2002 48v club car S/N: AA0238-204298 and it seems like it isn't getting full throttle. When it goes up even the slightest incline you can get out and walk faster then drives. The batteries are new and fully charged and I have 49.9vdc, with the key on, at the controller between B+ and B-. Looking at the schematics I downloaded it looks like the yellow wire coming from the multistep potentiometer is the speed controller reference signal. I unhooked the yellow wire from the controller and when I press the pedal down I get 0-7vdc.

I've gone through the normal troubleshooting steps by checking wire harnesses and connections for cleanliness and found no problems. It’s all looks original and I think that the only thing that has been changed is the batteries. Any troubleshooting advice would be greatly appreciated.

BGW

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rdaystrom

What type of batteries are in the cart? Fully charged it should show about 51 or 52 volts across the battery pack of maybe even higher. Proper water level is super important. Clean battery posts and lugs. ( And I mean clean!) None of this Oh it looks pretty good stuff....take the wires off and show me shiny metal surfaces!!) Clean un-corroded wires of a large gauge . (6 gauge or better) I like bigger wires personally. My Club Car has 2 gauge welding wire with solid copper soldered lugs.
Recheck the water levels. Recharge the battery pack to full charge. Start with super clean connections and good wires. If you have 51 volts or more several hours after charging you can move along to diagnosing the problem from there. Also be sure the cart rolls freely and the brakes are not dragging. Tires inflated properly.
I know that the more experienced golf cart guys here will want to start you off with the above before getting into diagnosing more complicated controller problems. Good luck.

darrellinceres

Thanks for getting back to me so quickly.

The batteries are brand new Trojan T-875s and fluids are good. The cross over cables are new and everything is very clean. yes I see shiny metal. Cables aren't monster cables but they are the same size as the OEM. The batteries my not be totally charge topped off because he drove it here from our plant a block or so away but I know it was on the charger before that. The cart rolls freely, I can push it back and forth and doesn't feel like it's dragging, And the tires are good.

darrellinceres

Okay,
So there is no one technical enough here to help on troubleshooting the throttle / control unit.

Well then maybe someone can point me in the direction of an upgrade motor / controller kit for this cart.

buckmanmike

I am not knowledgable on CC, but I think the throttle input is measured in ohms. At zero throttle should measure 5000 ohms and WOT should be 0 ohms. Also put the charger back on the batteries. It may take up to 12 hours to get a full charge on new batteries. Use the site search engine to find out how to properly break in those new batteries.

darrellinceres

It charges until the charger cycles off and I have left it on the charger for over the weekend. I just had our forklift service man test the batteries and he said they are fine. My manager is a large man so I think the next thing to do is look at a motor / controller upgrade that won't require a bunch of modifications if that's possible.

butterface

It sounds like the only thing wrong with the cart is that is needed to be charged and upgraded.

I would recommend upgrading the controller to a 400 or 500 amp controller, a solenoid to to match the amperage (white rogers 586 style will work with the 400 to 500), and 4 ga cables.

If you go back to recheck the throttle at the controller, you should check the yellow wire from the potentiometer and the purple wire and get 5k ohm at rest and as you press the pedal the ohm will drop to 0. MAKE SURE TO DO THIS WITH THE BATTERIES DISCONNECTED. I don't think that is the problem, but you may want to take another look.

Good luck.

wpns

Is it possible the reverse speed resistor switch is broken?

Does it go the same speed forward and reverse? If so, check the wiring on trhe outermost (rear) microswitch might be helpful. It switches a resistor into the speed control circuit when the cart is in reverse to limit top speed, and if it fails, can limit top speed always.

If I recall correctly, the actual resistor is inside the 3-pin connector, but a bad switch can cause the problem...