Just testing out a new build with dual motors 140kV 10S 4.12HW 3.34FW vescs with max brake current set to -25A. Wheels are pneumatic 175mm diam with 66T wheel cog and 15T motor cog. Sensored motors with sensorless above 7,000 erpm. Acceleration is very smooth .
The brakes are very smooth and fine coming from speed - but when slowing down at about 3km/h they grab quite hard . This is approx 3,000 erpm.
Any idea what is causing this ? . I recall reading somewhere that the vesc shorts two phases for final braking- maybe this is what is happening. If so - is there a setting to switch this off or to reduce the braking current a bit.
Thanks
The setting you’re looking for is labeled something like “minimum ERPM to apply full brake”, or at least it is in the original bldc tool and vesc tool. I haven’t used ack’s extended tool though.
I’m interested to know what this could be. I just switched to a new motor without changing any setting that weren’t crucially needed for a new motor and am having this happen below 5mph.
Exact same thing is happening to me on my Maytech motor. I am using vesc tool too.
Atm when braking I do not full break and use foot brake at the end instead.
Trampa mentioned in the past that bat min and motor min have to be more or less identical for linear braking in FOC mode. I haven’t tried it myself/switched to BLDC.
so were mine, except at low speed. That is the advice trampa gave based on my experience/exact same issue you are describing. Something to do with motor min being used predominantly at low speed. Worth a shot right? Set both bat & motor min at the min bat value.
crap, that’s a shame. Would be worth posting the feedback in the vesc-tool thread.
It would appear a fair number of people are having this issue with FOC.
So below is what I tried and it seems to work OK - Try below at your own risk
I an running dual DIYE 4.12HW vescs in FOC that came with 2.18FW. Updated vescs to 3.34FW using vesc tool 0.87.
The parameter “Max ERPM at full brake in current control mode” exists in BLDC tool but for some reason seems to have disappeared in the vesc tool.
So the first thing I did is to save motor xml file from vesc and then load it into BLDC tool. All parameters seemed to load OK into BLDC tool with same current and voltage settings.
Noticed that the value of “Max ERPM at full brake in current control mode” was 1500 erpm which corresponds to the speed at which the brakes were grabbing .
You may be able to adjust that setting in BLDC tool - then do a xml save and then load xml file into vesc tool and then download to vesc. I didn’t want to try this due to possibility that bldc tool could upset parameters in vesc tool and possibly fry the vesc.
So what I did was to get a xml file editor ( I used one from mediafreeware.com )
Then get the vesc motor xml file from vesc tool and load it into the xml editor.
Look for a line showing
The using xml editor - change the 1500 no to 200 ( about 1km/hr for me) with no other changes.
Then using xml editor save the xml file , then load that modified xml file into the vesc tool and then push motor config to the vesc. repeat for the other vesc if running dual drives
Note - one of my vescs came with 1500 for “Max ERPM at full brake in current control mode” and one was showing 500 . I guess these were different default settings on initial 2.18FW set-up and have not been changed by the vesc tool ( A bit strange!).
I changed both vescs to 200 erpm and it seems to work fine.
