VESC fw6.0 silent HFI testing + experiments

i remember trampa wouldn’t honour warranty of some of there big vescs because they were used with large pole count motors, stating they weren’t compatible
i’ve used hfi on 6 pole and 48 pole neither motor would even start rolling, just stutter screaming

@Evwan has a hobby of blowing up lil foccers on big modors.

The second one blew because of a bad motor :rofl:. Only one.


Linking @mackann sHFI test on 16s BioX esc. Phase shunts and silent HFI. Performs just like Vedders demonstration video.

Just a little click at throttle engagement, and then silent operation. So not as silent as sensors, but literally no annoying HFI whine to deal with. Pretty good option for 12s to 16s boards IMO.


Maker X d100s with 6355 maytech 170kv motors. Appears to work quite well on default settings with Coupled sHFI


joining the tester team, had to change a 2wd plutonium 2s’ motors from 65000’s to the new vented ones as the old ones would overheat on long lasting mountainous inclines (causing noise and physical resistance) in the hopes of being able to avoid this now, BUT now for some weird reasons me and support (markus I guess) were not able to actually detect sensors (if anyone got clues about how to get them detected by all means necessary, I would highly appreciate those) - so…

I am joining the 45deg silent team for now. the obvious right away: this hardware works very well with this mode, the first clicking noise is modest and not at all obnoxious enough to be annoying. then the 16khz tone at launch only kids and dogs can hear, but they did not complain either, so far so good. so how does it compare overall to sensored mode? DON’T cut your sensor wires yet :wink: - going very slow, this mode does not compare to sensored mode yet. yes, launches are close to perfect, if not indistinguishable to perfect, but the two remaining issues are going very slow. (want to get the board over a curb while protecting the battery case from scratches next to the board? so you lift the board with your foot, give a little throttle, it goes 3kph, lift the foot on the back, it is over the high curb. this needs sensors so far, as hfi silent mode does not like this stuff (I do this whenever I get home from a ride)). so it seems going very slow to pass obstacles confuses this mode somewhat. launching and essentially continually accelerating = no problem though.

second issue with this mode: smart reverse does not work at all: jerks around like sensorless mode. if anyone knows some settings how to fix this, would be highly appreciated, I use smart reverse a lot when breaking on a decline, and backing up the board if I overshoot the desired spot to come to full stop. but then again I wish I could go back to sensored mode, my sensor cables are flawless, the motors are less than a week old, and I (and support) can’t get vesctool to detect those pesky sensors. (cabling is flawless) I will let you know more about hfi mode as for now I will ride 45hfi silent exclusively.

if you have no possibility to use sensors, or if your motor does not have any (how much do they weigh anyways?) this is stellar performance for what it is. of course bioboards uses the ubox so it’s known to work well.

In my experience, sHFI performs better than sensors, but you need to take the time to dial in the settings.

Start by increasing the start and run voltage by a few volts, and decrease HFI gain to 0.1 or 0.15.

Try those changes and you’ll likely see flawless sHFI performance.

1 Like

is there a full guide for dialling in (s)HFI? or known settings for common motors?

Unfortunately no, this thread is probably the best collection of knowledge for sHFI. There’s just not a lot of people running sHFI or HFI.

I do think you’ll find it pretty easy to find settings that work well with just about any standard outrunner though. Hub motors don’t seem to like HFI, because they have low Ld-Lq inductance to overall inductance, compared to something like a 14 pole outrunner.

1 Like

then I think I’ll stick with VSS until this is a bit more idiot-proof

full documentation of the values to be played around with would suffice, vesc parameters look like Sanscrit to me.

1 Like

did you get yours to start slowly from standstill without rider on the board without causing jittery mess? what about smart reverse? so far I think it works nice if a rider is on the board, but I can not do a “KITT” on my board yet, older guys understand, as in “kitt, get over here”, “yes michael, whatever you want michael”

ok after some testing here are some good values for my BioX ESC doing the new 6495 motors: (only listing the ones I changed from defaults)

HFI Gain: 0.100
HFI Run Voltage: 7V (slightly better than 6v in my case, the 4V default is jerky a.f. here)
HFI Max Voltage 8V (only increased this as it felt it had to be higher than run voltage, no idea if it has to be changed proportionally to run voltage)


  • smart reverse works now, albeit it gives one single jitter/shutter, then it reverses normaly, I can live with this.
  • starting from a complete and absolute standstill with just a little throttle (really asking for it, nobody rides like this) can still give ze shakels, but as already noted, nobody rides like this, if there is even a miniscule movement in the motors it will be fine, if there is no movement in the motor but throttle is plenty enough (not like mode 1 half way but mode 2 half way or mode1 full throttle on a hoyt puck) then it will launch without problems from standstill, too.

now the big question. is this equal or better than sensored mode? in my opinion it’s mostly equal, but not exactly equal, if you really ask for it, and mess with the system by doing things slow as you would normally never do, sensors just know better where the motor is especially in those low speed environments or starting from a slope, rolling backwards and maybe lazy driving while someone walks next to you. is it better? definitely not. it is a very admirable and well working workaround for missing or broken sensors in my opinion.

1 Like

Yes, I’m not joking when I say it’s better than sensors. My board is flawless on sHFI 45.

Push the voltages up. Use my settings below. I’ll bet it gets better for you.

My 2 cents on Silent HFI:

I am running SKP 6485’s 151KV’s on my 12S6P Lacroix Nazare. One of the SKP Motor’s sensors do not work at all, so I started running Silent HFI. Silent HFI does take a bit of tinkering with in order to get it dailed-in, but once you have the settings correct - it is just as good as sensors.


I messed around for hours on the road today, small inclines and declines mostly, and silent hfi is not at all as good as sensors, breaking slightly at very slow speeds (around 3kph) makes motors rattle or knock, constant clicking gets annoying when staying under the speed limit for sHFI, i.e. driving next to someone wo walks, and smart reverse on small downward slopes is choppy even with values which work good on flat surfaces. all in all it’s solid if you don’t expect too much from it, but I will return the motors I bought as I want to go back to sensors, and maybe something is wrong with one of my motors as well (pretty big difference in values from motor detection), so ymmv.

What were your settings and what motors did you use?

The claim of “as good as sensors” is 100% predicated on having good motors and settings.


a pair of those - not sure if one of them is a lemon, can’t get it to detect sensors and values for Ld/Lq inductance are 10-20% off the other motor, i.e. when the other has 10, the suspect has 8 or 9… not sure if this means anything. anyways I even tried to manually change this value and it felt like it imrpoved things but still jittery in very special occasions, all involving standstill or near standstill operation as well as starts and stops on slopes/inclines/declines. only at those fringe usecases I got the occasional stutter which was annoying enough to call this not ready for primetime. I briefly managed to get both motors working in sensored mode by doing a motor detection without wheels attached (not sure if this made the difference, vesctool feels like a jittery hit&miss mess in itself in my experience) which finally detected at least one motor sensored, and by setting the other sensored manually, actually gave me perfect sensored operation for a couple hours and it was smooth like I am used to with sensored motors, no jitter, no skips, no comparison. but yeah something is off in my system, maybe vesc6 update, maybe some other freak bug or circumstance.

These are reacher motors, which should be able to work with sHFI.

If you are on something older than fw 6.0, you are using regular old HFI. not silent HFI.

Did you use the settings that I recommended above, or were you using default vesc settings?

Post screenshots of your motor detection settings (L and R and Ld-Lq and λ) and your HFI settings, and what Sensor Mode you are using.

And then again for the other motor, if you have more than one motor. (So 6 screenshots for two motors)