Code -06 question(s)

I have an October 2009 LC3 All Electric car that I am pretty sure is built on a GEM car chassis. It was purchased last December as a Christmas gift for my step-son. It seemed to run OK but quickly developed some charging issues and would display -06 error code some of the time. It had 8 Interstate 8V batteries and 1 “oddball” 8V battery all of unknown age/condition. I put in 9 Trojan 875’s and it worked fine for about 2 weeks and now the-06 code has re-appeared. Ideas?

check for sticking accelerator pedal. - unplug cable and spray with electrical cleaner.

I took the cover off the accelerator pedal assembly and all seems to rotate well inside. There are 2 micro-switches operated by cams as the pedal is pushed and a device below the cams operated by white plastic gears larger on the top connected to the cams/pedal shaft and a smaller gear connected to the device. It seems that the throttle will rotate and get to the first microswitch fine and shortly after is when the -06 code appears which is hard to tell if this is when that lower device comes into play. Additionally, I failed to mention in original post that the back-up beeper does not activate when switched to reverse. I found that if you put the car in street mode and turn the key off then the continuous beep comes on.