Thanks, MysticalDork.
The “Limit EPRM with negative torque” box was unchecked already, and the Max EPRM at full brake raised to 500.
BTW, since I have switched to the Li-Po cells, the Motor min (regen) and Batt min (regen) were raised to -60A and -45A respectively.
Battery Min at -45A is pretty steep, for troubleshooting that’s cool – but double check your lipo battery to ensure it can charge at that rate before using it extensively that way.
make sure the second minimum erpm box (the one related to current control mode) is also set to 500.
And like b264 said, you may want to set the batt. minimum to like -20 or so, -45 is a bit hard on the cells.
Yes, Batt min (regen) at -45A was a bit much. At the low RPM I am running, it’s never reached, except with the odd spikes.
For a normal ride, probably -20A is sufficient. The new Li-Po cells cost a bit…
Just to confirm, both Max ERPM at full brake boxes are at 500 already.
If I’m going slow enough. 1-5mph. Depending on how I hit the brakes my rear wheel sometimes stops and can momentarily drag the wheel. Is this what you experience. Or do you experience something different that feels like the board will stop and throw you off. What speeds are you experiencing this? I would say most VESC users on this forum with fairly normal settings can control their braking by increasing or decreasing controller input. It’s not a hard stop when going fast to slow. It’s gradual. However at slow speeds you may experience more abrupt but manageable stops.
When braking is activated, it comes in pretty well 100%, which really takes some getting used to. That’s why I was looking to do it gradually.
It is particularly annoying when I coast gently downhill (estimated at less than 3mph) and try to come to a “graceful” dead stop while keeping both feet on the board.
Occasionally at extreme slow speed, braking would disappear for no obvious reason, and I would need to release the throttle back to 50% and re-apply braking to get it back.
The braking behaviour of the VESC at low speed has been really perplexing. I guess not many would rely on braking as a feature.
At this point I have no clue what’s going on with your setup, but braking is extremely precise and controllable for me. 10s, unsensored bldc at 149KV with 5:1 ratio.
Just as as an experimental set-up to get to the bottom of my issue, I have hooked up a second VESC, hub motor and wheel combo to act as a simulated road surface to visualise the braking behaviour.
There were two interesting findings:
Gradual braking is achievable when the braking motor is running beyond 4000rpm. At lower speeds, braking appears to be a binary on/off action.
According to “Realtime Data” in BLDC Tool, the regen battery current in my set-up only reaches no more than -2.00A. Perhaps the Li-Po cells are a little extravagant.
Given observation (1), I don’t think I have a choice but to introduce some gearing to make sure a sufficiently high RPM even when coasting at low speed (estimated at 600rpm). The downside is that my top speed is going to take a massive hit. 