2016 ezgo txt controller output only half of battery pack

[justinsane]

2016 ezgo txt lifted. Battery pack holds at least 48.9 at all times. Solenoid positive terminal reads 48.9.
Solenoid other posts reads 48.3, I have read that anything between .03-3 difference is good, but have also read that the reading should have at least a difference of 3 volts. Dont know which one is right. Solenoid clicks and cart does roll in the stuck safety limp mode.

Checked controller output at the M terminal and B+ (possibly minus-checked the right one but did it last night and 5 year old fried my brain today). Reading without pedal push was 0.0, however pedal push maxed out at only 23.8 and read it should get all the way up to battery pack voltage.

B+ to B- was correct voltage.

Could it be the solenoid and resistor because the voltage is so close, is it the controller, or could it possibly be the speed sensor not allowing full throttle. Motor does spin when checking controller output.

Thank you in advance for any help, and hopefully my "rookie" self described this fault clearly enough.

Controller is a curtis 1206hb.

[JohnnieB]

Originally Posted by justinsane

2016 ezgo txt lifted.
1. Battery pack holds at least 48.9 at all times. Solenoid positive terminal reads 48.9.

2. Solenoid other posts reads 48.3, I have read that anything between .03-3 difference is good, but have also read that the reading should have at least a difference of 3 volts. Dont know which one is right.

3. Solenoid clicks and cart does roll in the stuck safety limp mode.

4. Checked controller output at the M terminal and B+ (possibly minus-checked the right one but did it last night and 5 year old fried my brain today). Reading without pedal push was 0.0, however pedal push maxed out at only 23.8 and read it should get all the way up to battery pack voltage. B+ to B- was correct voltage.

5. Could it be the solenoid and resistor because the voltage is so close, is it the controller, or could it possibly be the speed sensor not allowing full throttle. Motor does spin when checking controller output.

Thank you in advance for any help, and hopefully my "rookie" self described this fault clearly enough.

Controller is a curtis 1206hb.

1. A fully charged 48V battery pack ought to read at least 50.93V about 12 hours after charge shuts off. At 48.9V, your batteries are less than 60% charged. (See attached SoC chart - 100% SoC for other brand batteries may be higher)

2. A difference of 0.6V is probably okay. What you are seeing is the voltage drop across the pre-charge resistor which is determined by the amp flow through it, which in turn is primarily determined by the bleeder network on the filter capacitors inside the controller.

3. In the walkaway safety mode, the beeper beeps, the solenoid closes and regen braking is applied.

4. & 5. At 100% throttle, the voltage between M- and B+ should be the same as the battery pack voltage (at the time - pack voltage decreases as amps are drawn), but motor is RPM limited by the controller, so the voltage between M- and B+ will less than pack voltage after RPM limit is reached.

If you are checking this voltage with wheels of ground, the RPM limit will very likely be hit before the meter reading settles. You need two DVMs to accurately check this reading. One between the controller's B- and B+ terminals and another between the controller's M- and B+ terminals. Then check the voltages while climbing a hill steep enough to keep cart from reaching max speed for the performance mode the controller is programmed for.

You can also check the throttle input voltage to the controller. B- to Pin-2 (Black wire to ITS) should be from 0.7V to 1.3V when pedal is pushed just far enough to make solenoid click and from 2.2V to 3.2V with pedal on floor.

Also attached is a service manual for a TXT-48.

[justinsane]

I have no beep for reverse but didnt have a beep for it even when cart ran correctly.

I was told to push the cart to see if it beeps or if regen brake kicks in but nothing, was told that it should be speed control sensor then. It was kind of redneck engineering/testing so I dont know how much I believe this.

I checked voltage again using a spin wheel cause unfortunately there are really no hills in sw florida. Voltage between m and b- started at 0 again but only peaked at 23.3volts.

After recharging batteries, and letting sit for 12 hours they read 50.9volts now. I think earlier stated voltage was due to all the testing from all the forums I read. Thank you for the attachment, I will search through that tonight.