TXT48 Regen suddenly not smooth

[bronsonj]

I have a TXT48 with an Alltrax controller.

I have the regen set up the way I like and it has served me fantastically for a few years now. As of a few weeks ago, the cart now studders when I lift off the accelerator if I am at full speed. Like it's going into regen, then freewheeling, then regen and freewheel again until finally deciding that regen is OK and stays in regen as the cart slows. This happens quite rapidly.

I am not near the max V set in the parameters. I will charge the battery to 57.6V and 62V is the max in the controller. When this happened the other day I was down around 52V or 53V, well below where I normally charge to and well below the max.

Any ideas? As I type this I'm thinking maybe a data log would help. I've never messed with the motor on this cart. Do you think there could be a motor issue?

Thanks

[JohnnieB]

At max speed, the regen braking puts out its highest voltage, so it might be overvolting the controller or the BMS.

The XCT increases the field amps as the motor's RPM decreases to maintain a more constant level of regen braking as cart slows down, so there are lots of things that can go wrong.

Recording data logs that captures the studdering may help.

It'll show the max battery voltage and max motor (generator) voltage reached during regen.

If nothing jumps off the page, it'll be a good idea to contact Alltrax and send them the data log.

[bronsonj]

Thanks JohnnieB. I'll get to the data log in the next day or two.