But what ive read before FoC should be smooth at startup, even if you are running sensorless? Or am i mixing things up?
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Mixing up a bit. Foc runs quieter and smoother than bldc but from a standstill, I would still expect some cogging.
Yeah okay. Ill do some digging on HFI i guess 
Nevertheless, a slight push and your away. Doesnt matter that much 
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Yeah, I recently had a sensor issue arise and only could barely notice it. Hasn’t bothered me enough to tear everything apart.
I’m becoming an unwilling regular in this thread. This time I think my a/s bypassed Unity might finally have given up. I took it racing a few weeks ago and kept getting cutouts, most of which put me down on my arse. Metr reported a series of DRV faults…
The faults themselves don’t give me consistent and sometimes not even very detailed feedback.
I’ll admit to not really knowing how to interpret this info but there’s nothing that seems obviously over limits. But a DRV fault that itself declares that there are ‘No DRV8301 faults’? Does it think I’m some sort of idiot!? Like it can somehow bluff it’s way out of this!?!?!111 
The board had been running well all morning. It was only after a recharge that this started to happen and it only seemed to happen when I was getting hard on the gas.
I’m inclined to throw the fucking thing in the bin once and for all and then setting fire to the bin and launching it into the sun but if there’s the possibility of salvaging it by swapping out the DRV or by some other practical means, that’ll save me a lot of explosives.
I’ve got a Go-FOC DV6 Pro on the way to me in any case but any advice on how to diagnose the issue in the meantime would be appreciated!
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I’m sort of in shock, this goddamn thing took out four high discharge 3S 8Ah batteries on its way out. Just destroyed a couple hundred euros worth of batteries, discharged to zero while sitting idle doing nothing. I had a xenigotchi logging everything that looks like it shut down 2 hours beforehand for some reason, so no obvious record of what happened
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Good Christ! Short of it just spontaneously exploding, that’s gotta be every rider’s worst nightmare scenario.
Can you fill in some of the many blanks here? You were running lipos, right? …and presumably a Unity. Presumably no BMS? What state was everything in afterwards (besides the batteries apparently being flat)? Have you physically measured the voltages coming out of each pack yet? So many questions…
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yeah it’s confusing, I’m not ruling out me having done something very stupid. I had a charge only BMS with a 15A fused charge port. Each of the cells in the packs are reading <0.5V, some of them are negative, so they’re good and cooked. All the wiring looks intact, but the packs themselves look a little worse for wear.
Trying to work out if the marks here are a result of being overdischarged, or I damaged them beforehand and this is just me noticing
edit: one of the packs has started recovering, and is around 1.5-1.8 per cell
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Oof. That Unity, man. I knew we shouldn’t have trusted it.
That’s dead homie. (NVM, misread that you were trying to charge)
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Brutal with safeguards in place.
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I just know as soon as I take this haunted unity out of the naughty corner this is what he’s gonna do to my board next
So your unity, while off, drained the pack to zero. That is shit my pants terrfiying, about to go unplug playahaya jfc.
Are you sure the issue you had with the runaway board wasnt related to this? Can you show us pics of the unity PCB? Im really scared now. Over what time period did it drain to zero V? hours? days? weeks?
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Hihi, short answer yes. I think the unity wasn’t doing very well and then something catastrophic happened during the ride that both made it unresponsive and disabled all safety features, so it took the cells with it overnight. Drained over less than 24h idle. There is a small chance that the two are unrelated, or that the runaway board was caused by the battery problems and it went something like
- Started the ride, battery got near normal “empty” state of 3.5V/cell
- Unity should have cut off but ignored its cutoff and continued to go for another ~1 hour of very light to medium riding (the extra hour figure is based off when the Xenigotchi stopped logging, the first sign of fuckery)
- Runaway happened when batteries were already discharged below what they should have, as a result of low charge messing with the control logic or something
- The unity slowly discharged from whatever bad state they they were at (say 2.5V/cell) down to ~0.5 at idle because the antispark didn’t disconnect the battery
I don’t think that’s what happened though. My logic for this is that the board showed no signs of being low battery, and should have had a good bit of range left. I had 50% charge on a 355Wh pack when I left, was averaging 12Wh/km, and had covered about 8km. The pack should have been fine, even a really conservative calculation gives 5km range left
I’m not at home atm but I’ll post pictures of the PCB when I’m back. I coincidentally had just inspected the PCB without its heatsinks a couple of hours before taking it out because I was having problems with it not shutting down. Didn’t see anything hugely wrong, some details of what I’m talking about here:
(Summary of above: looks like my unity’s antispark is busted because it doesn’t respond to its power button and keeps supplying power to UART and the battery out even when it’s “off”. I did log it in its “off” state while I was watching for a few hours and then overnight when it seemed to be behaving, and it lost 0.7V total on a 50V pack, so this battery murdering behaviour is new)
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Did you get it from Amazon and did it work like expected?
yes
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Do you think this one can work
honestly not sure… plus it looks like that one is missing the pins
I can solder the wires to it, I was wondering if I can program it using the VESC SWD port. I think it’s cheap enough to try it. I’m going to order one and try it.
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