Ezgo dies after coasting

[JohnnieB]

Record a data log at the continuous sample rate and post it here.
You cannot attach the .csv (comma separated values) file, so ZIP it and post the .zip file.

Start with all switches off and turn them on one at a time with about a second or two between.

Drive long enough to get two or three instances of the cart misbehaving.

Also, bar graph meters are notorious inaccurate, get an inexpensive handheld DMM and use it for voltage readings.

[trippyork]

Excuse my ignorance,
I'm guessing a data log from the alltrax controller? and where are you wanting the voltage reading from? All my accessories are wired into a fuse block off of a voltage reducer.

[JohnnieB]

Connect a laptop or similar device to the SR controller via a USB cable (USB-A to USB-B aka printer cable) and fire up the Alltrax Toolkit program.

When the program finds the SR controller, check the log to file box on left side of screen. Select contentious. Browse to where you want to save file.

Tell the program to start logging and drive the cart until you get two or three instances of it not working right.

The press the stop button to save the file on your laptop.

I want the exact battery pack voltage measured. Also may need voltage readings at various test points.

Attachment-1 is a screenshot from a SR and Attachment-2 is from my XCT with the data logging stuff circled.

[trippyork]

ok, i logged into it. The low voltage cut off was 38. somehow I'm dropping below this and its cutting the system off until i reset it by turning the key switch off and back on. I have the original motor in it which was a 36 volt cart. I converted into a 48 volt cart but haven't upgraded the motor yet. Could the motor be telling the controller to shut off? maybe a short in the motor? I will try to get you the data as soon as the weather allows me to drive it enough. I have to drive a fully charged cart about 3 miles or so before it starts happening.

[JohnnieB]

DC traction motors operate over a wide range of voltages and the ones used in a 36V series drive work better at 48V than they do at 36V, and in a series drive the motor provides no feedback to the controller. However, the SR family of controllers do have short circuit detection/protection on their output, so a direct short between B- and B+ someplace in the cables or motor could shut down controller.

Since the cart has to be drive about 3 miles before it starts to misbehave, the problem is most likely battery or heat related. Fortunately the SR data log records 30 parameters excluding Date and Time, so the problem might be exposed, or at least pointed to.

[trippyork]

I hooked up a laptop and monitored the voltage. Turns out, when i gutted it and redid all the wiring, i put the keyswitch wire to the controller instead of the battery pack positive. When you let off the accelerator, the voltage dropped below cutoff and it dies. now with it wired correctly, it works.... thanks for everyones help

[JohnnieB]

Thanks for the feedback.