The Kart
Seventy-two volts, a 20Ah pack, and a throttle that took three weekends to stop lying to me. This page is the known-good tune. If it ever drifts, everything to put it back is below.
Gas to electric
An old MBA racing kart
A vintage MBA Kart Division chassis on a purple frame, still wearing its gas engine and a set of hard slicks. Good bones, tired everything else.
72 volts, same frame
Gas engine out, electric motor and a 72V pack in, new side pods and sticky tires. Same purple MBA chassis — completely different animal.
Hardware
Controller
Motor & pack
The bog
For weeks it wouldn't launch. Stab the pedal from a dead stop, wait, then go. Felt like a slipping clutch on a machine that doesn't have one. I chased current limits, ratios and start torque before I found it.
The pedal swings 0.74V at rest to 4.27V at wide open. The controller's ceiling was set to 4.0V. Push past the top of the declared range and it stops trusting the signal — so full pedal came back as 27 counts out of 256. I was standing on it and the controller was hearing a nudge.
Ceiling to 4.5V, floor to 0.9V. That was the whole thing.
The tune
Throttle
Ratios in Speed
Ratios in Gear
Current & motor
Functions
If it drifts
- Check the throttle range first. Low 0.9V, High 4.5V. If either reverted, that's your answer and you're done.
- Confirm both pins read 13-Invalid. SpeedLimit and Anti-theft. Back out of the page and re-read them — they don't always stick on the first save.
- Ratios in Speed, 500–3500 back to 100%. If anything got dialed down in the low range, put it back.
- Switch to high gear (PIN3) and launch it. Short stabs at full throttle from a dead stop, six or eight times.
- Still bogging? Now it's too much current, not too little. Drop MaxPhaseCurr from 260A to 150A and test again. Watch motor temp between runs.