Speed Sensor Problem

[Fred Blackman]

My '02 PDS Ez-Go will run fine, and occasionally it will sudenly decelerate, as if it was going down hill. Sometimes the motor will even lock up the wheels for a bit. If I stop, wait a bit, it will then go OK. But, it seems to really discharge the batteries fast after doing this, and the guage goes down quite fast. Also, it will not come up to normal speed. Can I disconnect the J5 pin, in the controller, and will this stop the braking action. Thanks

[JohnnieB]

Welcome to BGW.

Without J-5 plugged in, the cart will only creep along.
The motor speed sensor sends 8 pulses per armature revolution to the controller and the controller uses that information for all sorts of things, so it rebels when it doesn't get it.

Controller might be going into Low Voltage, High Current or High Temperature cut-off mode.
Try putting controller in Diagnostic mode and count to beep when the cart misbehaves.
Here is the controller cover label listing the different codes and it tells you how to get into Diagnostic mode at the bottom.

Might be a intermittent connection, wire or switch causing the solenoid to deactivate, which would cause the controller to go into the "Walk-away" safety mode and apply 100% Regen Braking.

Other than going to an aftermarket controller, there is no way that I know of to completely turn off the Regen Braking.

Also, what is the battery voltage?
It the SoC meter you refer to is a bar graph type, don't trust it, use a DVM.

[Fred Blackman]

I have ran diagnostic and get no codes. Also, when the cart goes into its' slow down, the buzzer will go beep, beep for awhile until I stop. After a short stop to hit, it will go OK for a short distance, then slow again. With load meter, I get 6.2 and goes down to 5.8 or so after about 7-10 seconds. All batteries tested about the same + or - a bit.

[JohnnieB]

Originally Posted by Fred Blackman

I have ran diagnostic and get no codes. Also, when the cart goes into its' slow down, the buzzer will go beep, beep for awhile until I stop. After a short stop to hit, it will go OK for a short distance, then slow again. With load meter, I get 6.2 and goes down to 5.8 or so after about 7-10 seconds. All batteries tested about the same + or - a bit.

Those batteries are sick or not charged. 6.2V is about about 70% charged and 5.8V is about 15%.
So they are going from 70% State of Charge down to 15% SoC in 10 seconds. That definitely waves a red flag.

Put the batteries on charge and then, using a DVM, measure the battery and battery pack voltage 12 hours after charger automatically turns off.
The voltage should be in the neighborhood of 6.37V per battery and 38.2V for the pack, or the batteries are no taking a "full" charge.
(Here is a SoC chart that gives SoC % vs voltage. Use the 6V column for individual battery voltage and the 36V column for pack voltage.)

After taking those readings, drive the cart until it misbehaves and measure the pack and individual battery voltages again.

Post both sets of reading here.