Alltrax 48500 not powering unless hooked to computer

Jdonley

1999 EZGO TXT Series (Fleet) – Upgraded to 48v, Alltrax 48500 controller, 400amp heavy duty solenoid, Reversing contactor and 2 ga cable set, AMD Beast 11.8HP motor.

My first time posting here and first golf cart I’ve ever owned. Originally it was a 36v system. The cart suddenly stopped one day while driving. I decided to perform the previously mentioned upgrades and convert to a 48v system. After performing the upgrades, there were some quirky things, but thanks to BGW post I was able to figure out the microswitch in the foot box had broken. Also, the throttle plunger was set almost ½” off where the collar was seated well behind the microswitch and clearly pressing the pedal broke the activation lever on the microswitch. I adjusted the plunger to factory specs, 17/64ths space at rest to ITS sensor, I believe. The microswitch appears to be disengaged at rest and activate upon entering the ITS confirmed with continuity on the digital meter. Because of what I’m writing about below, I also replaced the ITS sensor.
The issue I am having (I think) is powering up the Alltrax controller. If I plug the controller into my laptop, the cart functions perfectly. Forward and reverse and reversing contactor as well as the solenoid engaging. The cart will drive forward and reverse with no issues and I can switch directions and in and out of neutral without any issues and the cart continues to power up the LED on the controller. However, once the controller is unplugged from the USB, it doesn’t work except on rare occasion I can see the controller power up and then as soon as I switch direction or turn off the key, it will not work again.
My pack voltage is 50.8. the B+ to B- measurement is 48.8 volts at the controller. The pack negative to first large solenoid post is 50.8v. IF the solenoid clicks, the second big post on the solenoid is 50.8v (with resistor removed). It measures 2 volts less when the 470 ohm resistor is installed between the big post. The solenoid when wired from the KSI (J1) negative of the controller won’t allow the solenoid to close (activate) when in normal operation mode. If I run a separate wire from B- to the small negative post on the solenoid, the solenoid will open and close in neutral corresponding to pressing and releasing the foot pedal. If I put the rocker switch in F or R, the solenoid will activate with pressing on the pedal, but when I let off the pedal, the voltage on the second big solenoid post remains equal to the first post (when the resistor is removed), indicating it doesn’t open until I put the cart in neutral Then the solenoid will open. (Perhaps this is normal operation, but it is different than how it works in neutral).
I checked the throttle voltage following the trouble shooting from Carts Unlimited. When B- is measured against the small white wire (J4) it should read 8-10v. Mine reads 4.55v after the microswitch is activated regardless of how much the pedal is depressed. When measuring between J4 and J5 white and black wires, the voltage should be 10-12v and mine reads 2.7v. I’m not sure this means a lot since the reading is from the controller and this is when I can’t get the controller to power up. In order to get these readings I had to run the wire from B- to the small post on the solenoid. Other wise the solenoid wouldn’t work.
My wife jokes and says just drive around with it hooked up to the computer. But the connection to the controller and computer is not easily established. I turn on the key, plug in the cable and open the program. But it seems I have to wait a while for it to connect. Any insight on where I should try to focus on fixing this issue? Thanks in advance.

BGW

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WalterM6

I'd start by looking at the Controller setting in the Alltrax Toolkit. Open up the Controller Setting tab. There will be the three setting at the top of the page. The first will be called KSI. Set it to 24v. The next will be the Min Voltage set to 40V. Next set the Max voltage to 60V. Check these and let us know.

meyre1

If your cart had the d style charge port that has been changed you need to connect the red and white wire that comes out off the wiring harness to power.

JohnnieB

Do you have a SR48500 controller or a SMP48500 controller?

In either case, the trick is to get the controller to power up without the laptop connected. The SR and SMP controllers power up when the KSI voltage exceed the KSI voltage setting set by the KSI voltage slider. The default value is typically 24V, but check to be sure it hasn't been increased to too high of a value.

Then measure the KSI voltage applied to controller when the pedal is pushed. If it is less than battery pack voltage, trace the wiring back to the voltage source.

Also, can you hear the main solenoid click when the cart is misbehaving?

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FWIW: 40V might be a little high for the under-volt setting. 1.5VPC (Volts per Cell) is the absolute minimum, which is 36V for a 48V pack, so a volt or so above that should suffice. The latest version of the Toolkit manual states 38V is typical for a 48V pack.

Jdonley

WalterM6- Thank you for your reply. I changed the throttle settings. They were set on 16v KSI, 20v Min, and 55 max. I took your advice and set to 24/40/60.

Initially with the cart in neutral, the controller powered up allowing me to press on the pedal 3 times. I put it in gear and it did not work at all. It would not power back up when I put it in neutral again.

These likely don't mean much,but an observation. When I first turn the key on the cart, the controller led blinks a microsecond green. This only happens after the cart has set a while and powering up for the first time in a while.

Also, in the software when I click on the monitor tab, all of the error flags initially highlight and the shutdown has a black fill dot for a quick flash and then the cart operates normally without flags (again it is plugged into the controller the entire time) just after the microswitch is engaged as I am pressing on the pedal.

Jdonley

Meyre1- Thanks for the reply. To confirm, this does have the D port. I purchased all of my upgrades except the motor from Carts Unlimited. I received a fantastic wire schematic that I double checked to make sure everything is wired to spec.

I checked the voltage after the reed switch as well as the terminal red as it attaches to the small post of the positive solenoid and the voltage is the same as the battery pack (50.9v). The path is the white wire from the receptacle to the red wire to the blue wire to the key switch to the greenwire to the microswitch in the footbox to the red wire to the small positive post on the solenoid.

I checked continuity as well as voltage as a total system and the individual segments.

Jdonley

Johnnie B- Thanks for your reply!

I can confirm this is a 48500 SR. The settings were originally 16v on the KSI. WalterM6 above suggested changing the settings and I did change this to 24v. It did not fix the problem. I'm curious, if this is a minimum voltage setting, could I set it really low to 2 volts? I'm guessing not and I don't think it'd work based on what i discovered below.

I also measured the KSI voltage. When the computer is unplugged from the controller, I can confirm the red lead is 50.9v. This is the wire from the small positive solenoid post to the Red KSI in J1. When I pulled the black wire off of the J1 at the controller and measured the negative spade connection, it would not record any output. I measured this with digital meter on the J1 Black spade terminal on the controller and the positive digital meter lead on the wire on the small solenoid positive post.

If I have the controller plugged into the computer, the black negative spade in J1 records 50.9v and of course, the entire cart works perfectly.

I also checked the B- to B+ on the controller and measured 48.8v.

The solenoid does not click when it is misbehaving. I assume because the only negative input to activate it is from the controller, which isn't working. It will click if I run a cheat wire from B- to the small negative post on the solenoid. (The cart still won't run with the cheat wire). Does this indicate it is a controller issue?

I also ran a check of the ITS. When the cart is plugged into the computer, white wire to B- is 7volts. If I depress the pedal to full throttle it drops to 5.7 volts. Measurement across the black and white wires of the ITS is only 6.23v. All of these readings are more voltage compared to when the controller is not plugged into the computer, but some are still under norm reference.

One thing to mention. I saw in the alltrax controller manual that when the computer is plugged into the laptop and not getting ksi input, it will not send power to the motor. When I have the cart in neutral I can watch the voltage being sent to the motor. If I click the rocker switch in gear, the cart will take off. Perhaps I didn't read the manual correctly. But my impression is the cart should not be able to go. Thanks for your questions and helping me.

Jdonley

JohnnieB- I just reread your post and saw the last part. I will change the settings again, especially if I can get this figured out.

JohnnieB

The controller should have worked flawlessly with the KSI, Min and Max voltage as they were originally set. (Except when the charger had just turned off and the battery voltage was above the 55V high voltage setting.)

You should only have 50.9V on the KSI jack (red wire) when the pedal is pushed. Also, when you do have pack voltage there, does the LED on the controller flash green four times and then go to solid green.

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FWIW: With the black wire off the -sol terminal, you will always measure 0V if the DVM is referenced to B-. The voltage measured on the -sol terninal when black wire is connected is feeding through the solenoid coil and is supposed to drop to 0V when pedal is pushed, energizing solenoid.

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Checking the ITS is way down the list, but:

To check the ITS voltages on a SR controller measure between the white and black wires while they are connected to the controller. When the pedal is pushed just far enough to make the solenoid click, you ought to get 10V and when pedal is on floor you ought to get 6V.

Jdonley

Johnnie B-

I can confirm I only have 50.9V on the KSI jack (red wire) when the pedal is pushed. I do have pack voltage there when I press on the throttle. I just went to the cart and in neutral, with the cart unplugged from the computer, I got the four flashing green lights followed by a solid green light 8 of the 12 times I pressed the pedal. If I put the cart in F/R, it will not light up. Also the cart seems to light initially upoon turning the key switch; however, when I keep trying to activate the cart it becomes unresponsive unless I let it sit for a little while. I have never had any error codes on the controller. I only have had the four flashing green lights and then solid green. On one rare occasion this worked while in forward and another when in reverse and I was able to drive the cart and it worked great. Then once I switched the forward to reverse it wouldn't work again.


Something to note as you wrote, "With the black wire off the -sol terminal, you will always measure 0V if the DVM is referenced to B-. The voltage measured on the -sol terninal when black wire is connected is feeding through the solenoid coil and is supposed to drop to 0V when pedal is pushed, energizing solenoid." The controller was not lit up (powered), but I measured the B- to the small negative solenoid post with the wire attached from the controller. It measured 0 with the pedal at rest. When I pushed the pedal, it went to pack voltage (50.9v). Is this the opposite of what you stated should happen? Also, this is when the controller isn't lighting up.

A few minutes later...
I just went to confirm this and the controller lit up this time. When I measured the voltage at the small neg sol post with the controller powered, it only registered around .8 volts when the pedal was pushed. It didn't register any voltage prior top pushing the pedal.