Cart Still Running Hot, Still need help, please

[Sergio]

I don't know how an Open differential can work differently on a Golf Cart, perhaps there was some misunderstanding with the source that told You to only make 1 revolution of a single wheel .

Counting the teeth could be tricky depending on the differential, the 3 piece Graziano 1:12.315 ratio has a double reduction, so it would not be just Ring Gear/Pinion Gear calculation.

[mrgolf]

why not just remove the speed sensor put a mark on the end of the motor shaft and roll cart while counting how many times the motor turns to one turn of the wheels on the ground. might be a little hard but it can be done.

[greg-g]

You can use a volt meter on ? I think 1,2 or 3 the green and black wire and measure the speed sensor pulses + 5 and - 5

[MyCousinVinnie]

I don't think a series motor has a speed sensor. At least I'm not aware of one on mine.

[mrgolf]

Originally Posted by MyCousinVinnie

I don't think a series motor has a speed sensor. At least I'm not aware of one on mine.

My bad, I should have read more. if you can get to the motor shaft to mark it, you can still check it that way.

I have lay down under vehicles and had people push them many a time to check the gear ratio. Sometimes you have to slide a little at a time to keep up with it.

[scooterman]

Have you tried swapping out with another controller?

I thought it is a clear easy way to figure the gear ratio but it seems there are a lot of different opinions on how to calculate it. I thought stock was 10:1 on these carts?

[MyCousinVinnie]

Ask what should be a simple question and get a very confusing answer. Here is what I have determined so far about gear ratio: If you ask 10 people, you will get at least two and maybe three different answers as to how to do it.

If you ask someone how to get the gear ratio for a car/truck with an open differential, they will tell you - absolutely you must turn the tire twice. I've asked more than one auto mechanic the same question and they say the same thing.

That's all I can tell you. I have a call in to Club Car now to see if they can find someone who knows.

[MyCousinVinnie]

Here is a follow up post so that folks can know what is going on in case I might be able to help someone else one day:

I spent a good deal of time working on the cart today. Here is what I found out:

(1) It has about 12 1/4 to 1 gear ratio. The owner's manual says stock is 12.28 to 1, so that would be about right.

(2) On a cart with an open differential (which is a stock cart), you MUST do one of the following: (a) rotate one wheel with the other held in place or on the floor, but rotate it TWICE, or (b) put both wheels on the ground and roll them ONCE while inching along the ground to count the number of shaft revolutions.

How do I know this? I did it myself, with some help, obviously. If you rotate the wheel once with one side jacked up and the other on the ground, or you hold the opposite wheel and just rotate once, you WILL NOT get the correct gear ratio. You will get about half the correct gear ratio. I confirmed this by rolling both wheels on the ground and watching the shaft with a tape on it to confirm number of revolutions.

(3) Counting the teeth on the gears will get you nowhere. A golf cart is not like a car. A golf cart has a large gear, an intermediate gear and a pinion gear and then another pinion looking gear. You can count the teeth on any combination of these and divide by what looks like a pinion gear, and not get anything that will divide into each other to make 12.28. I tried this myself. I counted teeth and wrote the numbers down till I was sick of multiplication and division.

(4) My cart still flies like the wind. iPhone app has it going 25-26 mph. This is with the controller turned down to about 450-500 amps and the acceleration turned all the way down.

(5) Highest temp reading I could get after 15 minutes of driving was 120 degrees Fahrenheit. That was with an temp gun from AutoZone.

So, we are going to put the thing back together, and I am going to run the cart and keep the heat gun handy. I'm also going to shop for some smaller tires - go down to 20 or maybe even 18.

According to the speed calculator on this website, and assuming my iPhone app speed is correct, I am turning out about 4500 RPMs on the motor. I am going to check with PlumQuick to see if that is too high or not.

At this point, no one has any ideas why this golf cart runs this fast when everyone says it should not. Some folks would be thankful, I guess. I don't want it to run this fast. I'd rather have torque and a cool motor, but 120 degrees isn't bad. Let's just hope it stays that way.

Will update in case anyone is interested or in case someone runs into a similar problem months or even years from now.

[Sergio]

I am glad You came to the right conclusion about how to measure the ratio

I hope 120F is not what You have been calling hot.

Those motors have a class H temperature rating, which is 180C or 356F.

You have a long way to go before it gets hot.

Enjoy the ride.

[MyCousinVinnie]

No, that is not what I've been calling hot. Hot was 200 or more degrees F, which is what I've been by PQ begins to degrade the motor.

Thanks for your help.