could swapping to 2wd just to have the board running for now be viable?
It’s a rear ESC that failed, so that would be front wheel drive. Might be kinda silly. And the front ESCs are probably at the same risk of failure, too.
Just so everyone’s clear, the battery is symmetrical. It’s not like both terminals are at the back and there’s extension wires for the front. There’s one terminal at each end, and the front and back both have 1 extension wire to the terminal they’re missing.
I was thinking just swap one of the front esc’s to the rear, then yank the other front esc entirely
Then it would have less thrust than my other board, and still at risk of ESC failure. There’s just not enough time to overhaul this AND get practice with it before the race.
This is also a new board with experimental trucks, I’m not going to be faster on it if I don’t get familiar with the handling.
If I wanna do something, it might be possible to put the kart tires on my other board for more grip. I’ll check the compatibility later.
EDIT: Nevermind it’s got 10mm axles
I’ll have to pull the dead ESC out so I can power the rest of them up to check this, but it will be at whatever the default setting is because I didn’t change it.
And yeah, I have the nice 1000 uF Panasonic caps
How many caps have you used? Is there such a thing as too much capacitance?
The only thing that’ll happen is some sparks when connecting. Otherwise, no.
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Just the stock caps
No additional caps, just the stock ones. I’ve added extra caps on my other 4WD build for the front system, because that has longer wires running to the back of the board. I thought I would be able to get away without extra caps by building this battery symmetrically and splitting the difference, but guess not (oof)
That effect can destroy loopkeys, but I have additional XT30 loopkey ports so I can plug in a smaller key with some big 20ohm resistor and add as much caps as I want in the future.
I keep wearing more and more hats but my skateboards keep setting themselves on fire. This must be a problem with the manufacturers.
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Super unfortunate about the esc popping. I’ll be curious to see where the damage lies. This is what mine looked like when it happened.
I’m not sure maybe, I thought that was residual residue from the burn that’s circled. But you could be correct 
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This was the other unaffected side.
I’d bet that was just the FOC set to 15–20 kHz. You shouldn’t spin the wheels by hand, either; free-spinning wheels are dangerous under full load. In theory, if you test the FOC at 25–30 kHz, your ESC will run a bit warmer and the motors a bit cooler. You will certainly get a higher motor sampling rate and be able to adjust the amperage to the motors differently, though it does slightly reduce the VESC’s ERPM performance.
Thanks for the advice about the FOC rate, I didn’t know that. The hand spinning was just to get them started because I haven’t hooked up sensors at the moment so they were having trouble on startup, and because I have no concern for my physical safety. Don’t worry about it.
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I wouldn’t be suprised if it was just simply spinning the wheels in the air that blew it. High voltage vescs can’t handle freespinning the wheels. I blew my first D100s in a similar fashion 2 years ago.
Since then I never freespin stuff. Board on the ground is the only way I touch remote… Even afraid from deliberately doing violent burnouts.
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Okay I’m learning a lot of stuff today LOL
But this is surprising to me because the size of voltage spikes should be related to the amount of current flowing, no? Do you know what the failure mechanism is for unloaded wheels?
Basically just don’t spin the wheels up in the air at all and you reduce blown vescs by a large number.
Not like testing in the air achieves much, bad soldering or config usually only surface themselves under high load anyways.
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The main thing I have to test is that the center point and end points for my legstick controller are set in somewhat the correct ballpark before I stand on it and get it dialed in, but from now on I’ll try to keep the wheel speeds very low when I do that.
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Yes exactly current should be proportional to voltage spike. To me this sounds like an unloaded spinup issue.
I haven’t confirmed this with actual data but to me the most plausible explanation would be that the vesc’s rotor position estimator loses tracking with our esk8 motors and fast spinups. When you lose tracking and don’t stop the switching, you get huge overcurrents motor side. But these happen so quick that the vesc sometimes blows before the overcurrent fault would trigger and stabilize things.
One thing with the SKP solo’s that sketches me out is that the recommended config is to have slow ABS overcurrent faults set to true - basically increasing the time an overcurrent needs to be present before it throws the fault.
If slow abs overcurrent is false, the chances of the ESC surviving something like this become much higher. But that means having to run a larger difference between the motor current you set and the abs max current otherwise you get faults all the time. The hardware values in the firmware doesn’t allow abs max to be set high enough to my liking for abs max current. I usually set something between 1.5-2x phase amps. Most vescs have noisy current measurements so unfortunately such a difference is a must in my experience if you don’t want faults to occur during normal operation.
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