04 Club Car DS won't go over 8-10mph

[KmanAuto]

Picked up a 04 Club Car DS, has the Curtis controller. Purchased Non-Running, and the thin green wire from near the controller to the ignition switch was burned up. Never found the reason why. Replaced that wire, cleaned ALL connections and terminals. Cart turns on and drives Great! Other than it is slow.

Batteries are good, 1 year old, and do not drop too much under load. They were taken out of a Neighborhood Electric Car that was getting a lithium upgrade.
Now for comparison, my other cart, a 91 Club Car with resister speed control has absolutely no problems hitting 20 mph on 36v setup, this 04 DS is 48v setup

Another thing to note, all batteries are low resistance (I tested). I used thermal camera to check all the connections and wires, and nothing heats up more than a few degrees above ambient. Wires between batteries are 4gauge, and the long runners to the controller and motor are the original 6 gauge.
I used my clamp on amp meter, and at full max accel going Up Hill (for additional load), my maximum draw was about 50 amps, which would give my max output 2400 watts. definately not hitting the 10,000 maximum.

At this point, not sure where else to look. I'm thinking possibly some of the Mosfets in the controller might have fried, if the previous owner tried doing something stupid like towing something large or running it with a heavy load too long. Terminals were very corroded and dirty when I got it, so that might not have helped either.

While testing, with the seat off, I manually lifted the reverse limiter switch, and that did in fact cut power by about 50%-ish (Keeping it technical!).

Any suggestions would be appreciated!
-KmanAuto

[NoleFan4Ever]

Is this a regen cart? (Sepex with Run/Tow switch and Fwd/Rev Rocker switch)

[KmanAuto]

Originally Posted by NoleFan4Ever

Is this a regen cart? (Sepex with Run/Tow switch and Fwd/Rev Rocker switch)

It has 3 micro-switches on the Fwd/Rev rocker. One I know is for reverse speed limit, which even while going forward if I manually lift that switch speed is cut in half. I see no switches for run/tow.

[kokkos88]

might be the speed sensor... I think you can check it by pushing the cart manually, while in «run» and in «forward». the reverse buzzer should buzz if the speed sensor works.

[Sergio]

No speed sensors or Regen brake on a Series cart.

Have you checked You are getting a full signal from the throttle?

I think your cart has the pedal group that wears out and prevents full throttle, here are a few ideas if that is the case:

Zip Tie Fix:

http://www.buggiesgonewild.com/elect...tml#post258017

Fuel Hose Fix:

http://www.buggiesgonewild.com/elect...ml#post1261051

If that is not the case measure the voltage on Controller terminal #3 (throttle wire still connected) from pedal up to pedal down.

[KmanAuto]

Originally Posted by Sergio

No speed sensors or Regen brake on a Series cart.

Have you checked You are getting a full signal from the throttle?

I think your cart has the pedal group that wears out and prevents full throttle, here are a few ideas if that is the case:


If that is not the case measure the voltage on Controller terminal #3 (throttle wire still connected) from pedal up to pedal down.

Don't know, that looks pretty difficult! Will give it a try tonight when I get home. Thanks!
What voltage should I be expecting on Terminal #3?

[Sergio]

The typical voltage range on Club Cars is less than 0.35v when the Solenoid clicks to above 4.65v with pedal all the way down.

[KmanAuto]

Looks like hose trick might have worked, sorta.

Went to put a zip tie on it, as shown in the link. noticed the back of pedal nub was bare metal, but the same nub on front of pedal had a cut off hose section over it. couldn’t fit a zip tie on the back as things were too tight. removed the hose off the nub on front, then had enough play to reinstall it on the back. since it’s pouring crazy right now, couldn’t take it for a ride, however i did block the wheels, held the brake and checked amperage again. this time i was able to hit a brief second of 100 amps and sustained for a few seconds of 90 amps. i didn’t want to overheat or burn anything up so didn’t keep on it. so it seems to have worked.

For terminal3, both my craftsman and hazard fraud multimeters concurred to about .50v when contactor engages, and topped out at 4.5 that i could tell. will take a ride tomorrow. have a bunch of capacitors in order so i can build a custom charger, once that’s done just time to drive!

Thanks everyone for the help, will update again after i go for a drive.

[KmanAuto]

Update:

While it seems amperage is up, top speed is still hovering around 10 mph, and for a 48v cart, acceleration is very sluggish. I have in hand a replacement used controller. Cart was sold to me being reported that the controller was fried, and since ebay has a ebay 10% bucks day, i snatched up a controller right away. Popped that one in just now. blocked the wheels and held the brake and full throttle is still yielding around 95 amps, which would be around 4500 watts. still only half of the expected 10kW output. so, trying to see where i should go from here. I measured the voltage drop today while driving, and at full throttle and 95 amps, i’m only getting a 2volt drop, which on fully charged battery is quite good. Seemed my voltage was fairly close to your expected for terminal 3. Does this thing have a speed sensor governing top speed? i can’t find anything pertaining to that in any manuals i’ve dug ip.

[Sergio]

The throttle signal has to be above 4.65v for 100% throttle.

Once you get the pedal to full travel if the speed is still not faster, then You need to look for a bad cable or connection.

You can start by measuring the voltage between Controller B+ and M- to see if it gets the same voltage you measured on the batteries while under load.

If that voltage matches, then measure at the Motor A1 and S1 to see if there is a voltage drop on the cables and/or FNR switch.