# Throttle surging...



## migreig (Aug 5, 2011)

Hey all,

I'm running a 1231c at 96v with a PB-6 potbox. I'm finding that at 0-40% throttle application the car is surging and won't hold a consistent speed. It doesn't do it when I accelerate, only when I'm trying to drive a steady speed. I suspect the pot box but I'm not totally sure, anybody else had a problem like this?


----------



## EVfun (Mar 14, 2010)

A worn pot box is a common cause of surging.


----------



## migreig (Aug 5, 2011)

EVfun said:


> A worn pot box is a common cause of surging.


Is there a way to test it or should I just odder a new one?


----------



## onegreenev (May 18, 2012)

Get a new one. Get a better one if you can find a better insert pot. Keep your frame. Just get the new pot.


----------



## domosher (Jul 10, 2011)

I have repaired over 100 1231c controllers many did suffer from an oscillation in the ramp voltage section I have a modification to correct this problem. one way to test for a bad pb6 is to place a 100uf capacitor across the two leads + terminal to center pin on the control and - lead to the bottom terminal and see how it responds if symptoms stay the same the problem is in the 1221c / 1231c
I have seen it many times.


----------

