I have made an electric scooter, using a 12080 motor, the Trampa 75/300 on a 12s battery. I have it running in "current no reverse brake ADC2" with FOC commutation. The scooter works fine, accelerates smooth and fast and brakes well, until going over 35mph or so. At which point using the brake "throttle" (a thumb throttle connected to ADC2) produces a slow clicking from the motor and 0 braking force. It clicks every second or so, until air resistance brings the speed back under 35mph the brakes will suddenly kick in and work as normal.
I have tried changing various settings but none seem to have any effect, can anyone suggest what is happening? and any possible solutions?
Thanks
Hi! Have you tried increasing brake amps and battery regen amps?
Mod everything!
Thanks for the reply :) I have indeed, however my current set up is: motor brake amps is -120 (any higher and the wheel starts to lock up under braking), battery regen current is -60. These settings should give at least some braking from top speed, but the vesc tool app read 0 watts and 0 amps in this weird fault condition.
can anybody help me with this? its pretty unsafe having no brakes at top speed on this thing.
What a monster with that 12080 motor!
Do you have a bms which might trip due to excess regen current? Since you are making use of the vesc android app, try the logging (under developer tab) to capture the controller state during the fault.
Did you calibrate the throttle and brake?
Hi guys, thanks for getting back to me :) the battery has no BMS, I balance whilst charging. The battery is a 12s5p samsung 25r pack (I realise im pushing the pack pretty hard doing these drag runs). I will try to do data logging the next chance I get, however when i connect the vesc to my laptop running the PC vesc-tool, and do terminal>print faults, there are no recorded faults.
Yes I have calibrated the throttle and brake using the input wizard on PC vesc-tool. The throttle and brake response is perfect BELOW 30-35mph, above which the brake will not respond properly. My guess is the VESC is somehow losing track of the rotor when the brakes are applied and the motor is spinning too fast. Full speed is around 50k Erpm.
I think the vesc is losing track of the rotor.
Are you running with hall sensors?
The motor is running in sensorless FOC mode
Can the battery take 60A of charge? Most batteries can't take more than 1C safely. Above that, it can overheat and catch fire. This may or may not be related to the braking issue at high speed depending on what kind of battery to are running and whether you have a BMS that is limiting the charge current. I have a much heavier vehicle and much larger battery but I never push more than 20A back into the battery. And I have plenty of braking force at above 60mph. I recommend you drop the batt negative current to 1C of your battery and leave the motor braking current at around -100A. See if that works.
NextGen FOC High voltage 144v/34s, 30kw (https://vesc-project.com/node/1477)
It can take that charge rate briefly, it doesn't have a BMS. I have tried many different combinations of max negative battery current and max braking current (including that one), none of which have made a difference. Im starting to think the motor itself is the problem, as its had a rough life. Also what ever settings I try, and follwing the advice on the vesc tool, I cannot get BLDC mode to detect the motor. It just twitches and makes a horrible noise. (but FOC setup wizard works without issue).
Have you found the issue? I had exactly the same problem. It got fixed when I increased max abs current. Seemed like when braking at higher speeds, the first impulse of current exceeds abs max current. After increasing abs current I get "jump" when starting braking. Seems like its losing cycnc with motor and thats why current jumps high, havent found fix for this yet... . I also havent got BLDC mode working, same symptoms that you have, but FOC runs pretty good.