First VESC died in less than 24 hours! For others to learn from my mistake, my mistake was to order a VESC without battery side external capacitors, and running a burned / poor connection XT90. XT90 lost contact while it was auto-detecting FOC parameters - there were welding sounds - and magic smoke. DRV chip has 2 big holes in it! Crash analysis is no caps - lost battery in the middle of a very oscillating cycle - voltage ripples over 60V which is the max for the DRV chip.
*Edit* I have later read that you should not do FOC detection with 12S battery, it is too close to the max limits of the chip, use a power supply with a lower voltage. (I tried that, bench power made some weird sounds and actually turned itself off! But that was without any battery side capacitors)
VESC 1 ran quite good the first day. 3,5 km uphill to work, full throttle the whole way, no sweat. Ran in sensorless FOC mode (because I didn't have the right connectors to hook up the halls). It did have startup issues though, half the starts would stutter and stop. But once it got running it ran strong.
VESC 1 from vesc.co.uk (which is in Vilnius)
VESC 2 from Ebay / Maytech (Hong Kong)
Vesc 2 does not like FOC mode at all! It would run (now I am in Hall sensor mode), but it would cut off at full throttle, throwing an ABS_OVER_CURRENT error. Every time, also, same error randomly at spin-up.
I should probably go back and test sensorless FOC to see if that makes any difference ?
Finally switched it to sensored BLDC mode, and it seems perfect. But maybe, a bit weak on very steep hills and standing starts, will test more.
I also noticed that after commuting to work, taking a horrably steep uphill (VESC went up to 90 C and was downramping), motor is not even body temperature! Feels ice cold! I am pretty sure I would burn my fingers on the motor if this was with the BBSHD controller.
So the good thing is that the BBSHD motor seems to have a lot of headroom. Bad news is that the VESC needs better cooling. And this morning was around 15 C outside, it will only get worse.
Picking inspiration from a raspberry pi aluminium cover that uses the whole cover as a heatsink, maybe I can glue/cooling-paste the FETs directly to the bike frame, to have the whole frame as a heatsink
That would be awesome, but probably impossible because cables and plugs are on the same side. Anyone know a way to waterproof AND cool the vesc at the same time?
I also noticed, watching the VESC Monitor Android app, which is awesome, that battery amps very rarely reaches my limit of 30 amps, but quickly goes down as the rpms goes up. This probably makes sense, but the old Bafang display reported 30A all the time, as long as I was on the throttle, even at the RPM limit. That was probably not right though, probably just a stupid interpolation of throttle input and not a real measurement. I just never realized that the bike should be quite economical.
Finally, here is my REAL motivation to run a VESC, the data and the logs!