A member of our community shared my enthusiasm for exploring sHFI tech and was kind enough to lend me these Trampa ESCs, while they push through the depths of winter and are prevented from eskating. I’m going to share a few videos below of the cool things that I explore here.
First up, getting the dremelseed ready for non antispark esc’s. Luckily I am a hoarder and from old purchases I already have a loop key and a panel mount loop key receiver on hand.
Two sHFI 45deg v0v7 silent launches. The only noise from sHFI is the ping at the start. I tracked this on metr and both launches were about 150a total.
Low throttle weirdness on 45deg v0v7 silent HFI
I’m going to play around with start voltage and see if I can make this go away
Normal HFI for noise comparison
Coupled v0v7 silent test - no more odd low throttle behavior.
3 good launches at full throttle. 75-80a each side. Metr was connected but didnt record 
Finally got a flaw in a launch… SHFI is pretty awesome but apparently still can’t handle the abuse sensors will tolerate.
After a couple hours testing, sHFI is a big step forward from regular HFI. It launches pretty well.
I did manage to get one instance of cogging, but in real riding I’m not ever riding backward down a hill and launching, so I’m happy with the performance I have seen so far.
Also worth noting, I did zero tuning of this setup. sHFI has enormous potential to make sensors obsolete for 10s-16s boards (limitations of phase shunts currently) but only if VESC project implements a wizard to tune HFI parameters.
I really wish silent HFI worked with stormcores, because I would be very happy riding this on my board that lacks sensors. The normal HFI whine is ok, but I prefer the silent operation.
Pretty cool stuff overall and I’ll be testing it more. Feel free to suggest ideas and things to test.
Quick neighborhood rip just to test the metr logging. Auto logging is not reliable but maybe that is a 6.0 fw issue? Seems to work fine when i tell it to turn on.
Anyway I hit highish amps several times and sHFI was seamless. If you have a vesc design with phase shunts, this is a great option if your motors don’t have sensors or if they break.
I’m not convinced it’s better than sensors but I think for 99% of riders, they wouldn’t be able to tell the difference. And if they could, they wouldn’t care.
This is great testing, and really shows how far sensorless startup has come, especially with no tuning. Thanks for taking the time to put it together.
Hopefully more people can experiment with it and post results in this thread.
It’s worth pointing out some details about these ESCs. They are from the first and second batches of VESC 6s released back in 2017 and do not have phase filters. It wasn’t until quite a while later that phase filters were added to the hardware in the MK5 series and above.
If anyone has an ESC with both phase filters and phase shunts it would be really interesting to compare results and see if it resolves some of the issues shown here.
Here is a list of ESCs that have both. There may be more out there.
Spintend Ubox 75v single and dual, all versions. Not the 100v. Spintend states on their website that Silent HFI seems to be working well on these controllers.
Trampa VESC 6 MK5, MK6, HP, 75v, and EDU
Trampa VESC 75/300 R2 and above
A list of ESCs with at least phase shunts (like was used in this testing) can be found here:
The silent HFI looks like it had less kick than screaming HFI?
I think it’s just the way i was throttling in the videos but i can check later and test with that in mind.
Update - I tried switching back to HFI to see what it feels like on fw6.0. I heard that HFI was upgraded so I was curious.
I did several flat ground full throttles and every single one resulted in a motor fault where I had to jump off the board.
So from my very short test, it seems that sHFI is way better than original HFI in high current bursts.
I made a discovery tonight while playing with HFI settings on my stormcore 60d+.
I got all the new modes of sHFI to work! They are not silent, but quieter than normal HFI. These new modes also handle more amps than normal HFI so they should improve sensorless performance.
To get sHFI to work with motors reliably turning in the desired direction, I reduced the default “HFI gain” from 0.300 to 0.100
let’s do a drag race! i’m onnnnnn 5.1? 5.2? on HFI on my thane board
Set one side as HFI and the other as VSS and see which side pulls harder
I can’t recall if i have temp sensors connected on this board. Vss requires them, right?
Also, it’s not really which one kicks harder. They should kick the same. The thing is VSS will likely fault out at lower amps than 45 deg or coupled v0v7.
