96 EZGO top speed down 2-3 mph

[not-so-ezgo]

I am not an expert, but I will likely be soon.

I have been trying to diagnose a speed problem with my 96 Medalist. This is a 36v series cart. I installed all new batteries(mine were weak). Voltage on the pack is good now.

Top speed with this motor was 13-14 mph before having problems last fall. I will list the parts replaced and when issues happened.

Cart got slow (10 mph) and started dragging a wheel and grinding. I replaced axle/hub bearings. After reassembly top speed was 8.

I assumed brakes were dragging etc. Wheels would turn freely though..

Then a local "cart place" told me the motor was finally bad. So I bought a used motor that was good(per same guy)

Installed motor and was back to 9-10 mph. In my research I found the replacement motor to be a slower series motor than I had, so I assumed this was the case. Out of frustration I actually installed the original amd fleet speed motor and had about the same speed still.

Now to current condition - New batteries, Original motor, top speed 11.34 mph gps speed. 1 person zero grade.

Is there anything left for me to test (without taking to a shop) to know what is causing the slow down? I enjoy working on things, but due to cash flow I am not wanting to throw the amount of money at this I usually do to replace parts until it all works.

I know there is something on the pedal that controls voltage, and the FR switch that could cause this. I am sure I am missing something easy here, because these don't seem that hard.

Obviously I am wrong. lol

[JohnnieB]

What is the battery pack voltage 12 hours after charger shuts off?
A fully charged 36V battery pack should be 38.2V for Trojan brand batteries and clones, higher for some other brands.

The batteries ought to be charged after each use. Don't let them sit overnight in a partially discharged state.

Measure the voltage between the M- and B+ terminals on the controller. It should go up to 38.2V (or whatever the battery pack voltage is at the time) when pedal is pushed to the floor. If it doesn't, you may have a throttle problem, or excessive resistance in the high current cables, connections or contacts.

Attached is a schematic with high current circuit highlighted.

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I have to leave for a doctor appointment in a few minutes, but other can help with the information I asked for is provided.

I'll be back.

[not-so-ezgo]

I answered in Red Below for ease of reading. (I hope)

Originally Posted by JohnnieB

What is the battery pack voltage 12 hours after charger shuts off?
A fully charged 36V battery pack should be 38.2V for Trojan brand batteries and clones, higher for some other brands.I was at 38.31 volts

The batteries ought to be charged after each use. Don't let them sit overnight in a partially discharged state. I always charge when not driving. Charger shuts off when all set. Also charge every 2-3 weeks just in case when sitting.

Measure the voltage between the M- and B+ terminals on the controller. It should go up to 38.2V (or whatever the battery pack voltage is at the time) when pedal is pushed to the floor. If it doesn't, you may have a throttle problem, or excessive resistance in the high current cables, connections or contacts.I Will check this.
If I disconnect 1 lead from motor will that allow me to do this without driving?

Attached is a schematic with high current circuit highlighted.

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I have to leave for a doctor appointment in a few minutes, but other can help with the information I asked for is provided.

I'll be back.

[Sideways]

"If I disconnect 1 lead from motor will that allow me to do this without driving?"

I believe this should be done with the rear wheels off the ground on jack stands and only hold the pedal to the floor long enough to get a reading.

[JohnnieB]

Leave the motor and everything else connected.

You might find something with the tires off the ground, but it will be more revealing if the system was placed under the same load it was when the cart goes slower than it ought to.

Battery pack voltage and charging protocol okay.

Sorry, I had to ask, but it there is a lot of misunderstandings in those areas.