diagnostic test result

[joehrs]

99 ezgo txt series 36v


*CONTROLLER OUTPUT Connect (-) probe to M- terminal.*
Connect (+) probe to B+ terminal.*
The reading should indicate approx. 0 volts.
Slowly depress accelerator pedal.*
The reading should show the voltage increasing to battery voltage when fully depressed. If the voltage is at or near battery voltage and the motor is not turning, then the problem lies in either the forward/reverse switch, the wiring, or the motor.
If the voltage increases by a few volts and then stops changing while the pedal is being depressed, remove the orange wire at the "Reverse Micro switch".*
If the voltage is not at or near battery voltage, replace the controller.*
If battery voltage is present, the problem lies in the reverse circuit.*
Re-connect the orange wire.


Cart is running
passed all tests.......but is only getting 35.1v fully depressed
is this considered at or near battery voltage of 38?
Any ideas
thanks

[sportcoupe]

Adjust ITS throttle.

[JohnnieB]

When measuring between the M- and B+ terminals on the controller in a series drive cart, the voltage ought to at or about Zero when the pedal is just pushed far enough for the solenoid to click and then should increase to the Full battery pack voltage (at the time), less about 0.5V for every 100A of current flowing through controller.

If you are monitoring the voltage between M- and B+ while driving the cart, the battery pack voltage may very well have dropped from 38.0V to 35.1V while under load.

If you have two voltmeters connect one between the controllers B- and B+ terminal and the other between M- and B+ terminal. Those two readings should be nearly the same when traveling at max speed with pedal on floor.

If you only have one voltmeter, measure between M- and B+ and then measure between B- and B+ while traveling over same stretch of road.

If the voltage readings aren't almost the same (within 0.5V or so when traveling at max speed on level ground), than the ITS may be out of adjustment or bad. or the controller is sick.

[joehrs]

This was measured while on blocks

[joehrs]

I am trying to figure out why I have really low torque. Wont go up much of an incline.
good batteries,orig 6 g cables stock controller solenoid and fnr switch.

what do you think would be the first thing to fix or upgrade?
Thanks
ps is this stock or correct solenoid? I cant see the amp rating

[JohnnieB]

Looks like a stock 85A solenoid. Needs to be 200A or higher.
The 6Ga cables ought to be replaced with at least 4Ga. (all 13 of them)

What size tires?
What is the battery pack voltage while trying to go uphill?

[joehrs]

Johnnie b,
When sitting still bat pack v is 38.0
when full throttle full speed level ground 35.1
when starting up an incline it drops to 33
is this normal?

[joehrs]

When sitting still bat pack v is 38.0
when full throttle full speed level ground 35.1
when starting up an incline it drops to 33
is this normal?

[yurtle]

Larger tires kill torque, and even with stock tires, a series buggy will slow down going uphill, and the worse the batteries and/or SoC, the slower it will get. Even when my batteries were at the end of their life, I never met a hill I couldn't climb, but it got to the point where I could almost walk faster on steep hills with four riders. Since you have larger tires, the motor will pull more amps, so the voltage drop "may" be normal, depending on weight of passengers, battery SoC, and steepness of hill. May be time for an upgrade.

[JohnnieB]

Originally Posted by joehrs

When sitting still bat pack v is 38.0
when full throttle full speed level ground 35.1
when starting up an incline it drops to 33
is this normal?

It is normal for the pack voltage to drop under load. How far it drops depends on how many amps are being drawn, the SoC (State of Charge) and the battery's storage capacity. (Batteries lose storage capacity with age)

The 22" tires are costing you about 20% of the cart's stock torque, so it is going to draw a lot of amps and will be slow going up hills.

To turn those tall tires, you are going to need at least 4Ga cables, a heavy duty solenoid, a heavy duty F/R switch and a higher ampacity controller. Plus you may need to replace/upgrade the battery pack since it is dropping considerably with just a stock (275A) controller.