Sudden braking at hard acceleration

Hi guys,
I am running APS 6384 motors on two legacy Focboxes, powered by a 12s lipo battery. BMS is configured for charge only and I use a GT2B remote. I am currently running 60a battery and 80a motor. Since the last ride, my board tries to kill me during hard acceleration. It behaved completely normal before and still behaves normally at cruising speed.

My remote was fully charged prior to today’s ride and the motor phase wires are fine too. Unfortunately, I don’t have a Metr module to check which part failed.

Any advice?
I will try to re-bind the remote and check the wiring.

Cheers

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90% of the sudden cutouts are due to current path interruption issues. ie Bad series connections, motor connectors coming loose etc.
I would start there first.

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Or simply tight belts @taz :man_facepalming:
JK

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Did you happen to drop your remote or bump the trim on the gtb2 dials ?

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Not that I know of. I was racing through the night and only after 30-45 riding with no issues this mysterious problem occured. My remote was on it’s lower limit so I thought it could have been that. Went home, charged it up, went for a ride two days later, problem still there …

I noticed after the ride the remotes green LED was flashing, switched it on/off and since it was gone.

If you can somehow recreate it without to kill yourself I would give it a try to connected the escs to vesc tool after and check if there faults actual.
I had abs overcurrent faults when hard accelerating with my aps 6384s at 90A motor max and default absolut max settings. Pumping up the absolute max to 200A solved that issue.
Not sure if it’s your problem too, but worth a try.

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Flashing led on the remote sounds like bad news.
I’ve had this on a mini rc remote after a fall where it would do this intermittently if I hit the remote with my hand or even shook it.

If it’s not the remote I’m betting on a loose weld.

Regarding the remote.
I had a fall with my mini couple of months ago, then it stopped working. After opening I saw the battery tabs (that hold the dry cells) were bent, so the batteries were rattling and bot connected.
No idea if this is the case with yours but something to check.

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I will increase the total current, and then if it still doesn’t work change to the mini trigger remote. I had glitches on the GT2B on my old board before where it was suddenly accelerating out of nowhere.

I am not sure if series connection are an issue since I have 3x12s lipos in parallel. Even if 2 packs have an issue there is still a 3rd one. Most of my connections are soldered and those splices are dead solid.

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I had this too. You should check your absolute max current VESC setting. I had it set almost equal to my max current setting and when I hit it with full throttle it cut off because the absolute max was reached. You should set it at 150A or soemthing, it’s a peak current thing.

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Cheers! I only increased the motor current recently, so might be the issue then.

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Ok, lads, changed the motor current down to 75a and the max current to 150a.

You mean absolute max current right?

Edit:

Yes, that’s correct. Btw. the problem still exists. Next, change the remote …

Ahh that’s a bummer. I wouldn’t know what it would be then. Goodluck!

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I experienced this last spring. I fund that in a hard acceleration I reached 120 amps. And the focboxes apparently cuts throttle at 120 amps. Do you have telemetry data so you can see if this is the issue?

Chaka was the one that saw it:
"The vesc has a hard cutoff at 120 amps and in your app data you hit a peak of 120.7 amps. This only cuts throttle and does not shut the whole system down. It looks like your board is set up with a top speed just under 40 mph, this is high enough to start triggering these spikes when throttling hard at 50% duty cycle.

If you lower your max motor amps down to 50 or 60 amps it will give the soft cut off more time to engage and prevent the hard cutoff.

Motor detection should be with the motor free to spin, no belt or gears should be attached."

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Unfortunately not. Last night I was able to recreate the error, brought the board switched on home, disassembled the tray, while trying to plug in the usb connector the battery tray slipped across the table something must have touched the on off switch … all data gone :triumph:

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UHH man, you got not that much luck on this.
Sorry i cant help but wish you luck soon to solve the problem.