real technical question Non PDS Speed controller

[reb0957]

Here is my dilemna. I have been troubleshooting my 36v TXT for a week or 2. I honestly thought the batteries were bad but never had one that showed up until yesterday. In the meantime, I had ordered a used speed controller. It still isn't in.
Charged the new batteries overnight. Took them out for a spin and was only able to get the battery to 90% but plugged it in anyway. Let them charge fully again and took them out for a spin.

Completely stock cart.
Top Speed 12MPH.
It gets there and holds it well fluctuates an MPH or 2 on the road.

Hills of any kind it absolutely sucks.
small medium large or an anthill it sucks.
The voltage drops to about 33.5 on any size hill.
In following the testing diagram for a NON-PDS speed control. Some kind of way I got to number 34. It is figure 12 sheet 6 of 8. The ohms were actually in the 120ohms not in the 324 to 340 ohms it calls for.
MY question is could this be why I am dying on hills?

[JohnnieB]

Top speed on a 36V TXT series cart is about 13 to 14 MPH, so you are running a bit slow.

The most likely suspects are:
1. Low battery pack voltage.
2. Bad high current cables.
3. Bad high current contacts in F/R switch.
4. Bad throttle.

What make/model batteries?
When new, batteries only have about 75% of there rated storage capacity (AH) until they have been broken in, so you will see more voltage drop under load now than you will after the first dozen or two charge cycles.

A typical 36V 225AH pack drops about 1.0V per 100A of current being drawn from them. At 33.5V, you are dropping about 5V, which equates to 500A of current being drawn, but the max amps a stock controller will pass is about 275A, so the rest of the voltage is being dropped across the high current cables and contacts. (Are any of the cables getting hot?)

If the cart still has the original cables, they need to be replaced. All 13 high current cables should be 4Ga or thicker.

Sounds like you are following the troubleshooting tree in the service manual, or at least a copy of the pages from the service manual.

Lower Ohms than what is specified in Step-34 could be an issue, but the question is: Why/how did you get to Step-34?

What voltages did you get for Step-25 and for Step-26?

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All electric carts slow down on hills and Series drive carts slow more than SepEx drives or AC drives.

Bad batteries, bad high current cables and bad high current contacts in the F/R switch are the usual culprits for excessive slowing, but it could also be excessive mechanical drag from dragging brake shoes or bad bearings in the axles, differential or the motor. And the motor itself could have issues.

[reb0957]

I don't remember how I got there. Every test posted good, even the batteries until Monday morning. So changed them out. The only test that came back bad was that one. I am doing this on a budget. Just trying to keep my 83 year old grandpa playing golf.
I have learned and taken more things apart on this cart than I ever planned on.


Sent from my Nexus 6 using Tapatalk

[JohnnieB]

If you were getting 0.4V to 0.6V on the white wire (Pin-1) with the pedal up and 1.5V to 1.7V with the pedal down, the throttle signal to the controller is okay.

The batteries are new, so if the throttle is good, that leaves the high current cables, connections and contacts.

Clean all the cable connections and then take the cart out for a hard drive up a few hills and feel of the cables. If any are much more than 10°F above the air temperature, they need to be repaired or replaced.