Trampa VESC 6 issues (DRV fault, soft and hard cut offs during riding)

Hi guys,

I have some serious trouble with a @Trampa vesc 6 since yesterday and seeking for help or any ideas what’s going on here. The vescs were running flawlessly the last 2 years so I didn’t expect any problems.

I am trying to explain what happens since 3 rides. Often on hard acceleration there is some kind of a soft cut off noticable not dependend on speed, it can happen at 25km/h or 48km/h. BUT it never happend with full battery, it starts after a couple of kilometers and then it’s there until the end. Also it doesn’t feel like thermal throtteling on one side where the truck would start to wobble like hell (I had the pleasure already). For safety I checked the motors several times but both were just warm. Also all cables and connectors are fine.

Then I had a hard cutoff which was scary and dangerous. I was accelerating pretty hard from standstill on concrete and then suddenly a total power loss. I’m glad it happened on my MTB because without bindings = 100% streetface no doubt… Even with bindings it was tricky. Then I rode home the last 5km just with a few soft cut offs during hard acceleration.

At home I tried to connect Vesc-Tool mobile app

Huh?
The second time it worked, checked for faults… fuuuu**!
Too big for a screenshot so connected to Vesc-Tool on the computer.

Typed in “faults” in terminal but no faults, what??
The fourth try gave me the same result as on the mobile and afterwards no faults again as you can see.

over temp motor cutoff at 49.89°C is weird because I never touched the standard settings

fTempsetting

Also I don’t know why there is only 1 over temp fault if it’s the root for the noticeable soft cutoffs. I had really a lot, too many to count.

Second the scary DRV fault, I guess that was the total power loss I’ve got. 4.55V? :thinking:

Checked the slave vesc but no faults even after 10 attempts.

Then I wanted to connect the master vesc again

faultsecondconnect

second try

faultthirdconnect

third try worked :man_shrugging::thinking:

Has someone an idea what happened to my vesc or what I could do? :pray:
I’m running FW 4.02 (test version).

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First thing that I suggest is open the case. Check for a burn drv.

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When you brake the energy regenerated can’t be stored so the vesc goes :boom: :boom:
Definitely can’t be anything else then this

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“BUT it never happend with full battery, it starts after a couple of”

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Do you think the vesc would still work with a burnt DRV?

The “soft cut offs” happen during hard acceleration not during braking. Of course I can’t rule the BMS out but I’m quite sure it’s not the problem.

Can you still run motor detection?

Good question in 5 minutes I have an answer :grin:

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Detection works and I get similar values.

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Good to hear then the drv is fine. How high is your abs limit current?

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That’s the settings

s1

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To be honest after all the issues with recent firmware I would not trust the latest builds 100%.

I never do to be honest, I mostly lag behind letting everyone else test

I’m still on 3.62 with zero issues. I would attempt to try and use 3.62 (or other old but known good) and see if you get the same problems.

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What firmware?

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After upgrading to FW4.0 it was no more possible to downgrade (but it should be). Tried it for hours. Upgrading to FW4.02 was easy as usual. I’m stuck :man_shrugging:

FW4.2 but the test version Benjamin sent me to test before release. I could try to install the official release but doubt that there is a difference also I’m running this FW since 1 month without issues.

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I’ve moved from 3 to 4 to 3 to 5 to 3 without issue

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Solder the big inductor back in place. Your ride style probably removed it from it’s original position. The Inductor sits on the lower side of the PCB. Make sure to use a new heat pad. PM me for more info on that.

Is your battery pack dieing what’s your volt drop at heavy loads? Check the battery internal resistance.

That gave me a good laugh :joy:
But I just use 55A batt max each vesc :man_shrugging:

I want to try some other things before I open the case but then I’ll pm you, thanks. If you don’t mind it would be great if you could share the correct size (or even a link) of the heat pad here as future reference.

It’s likely a HW issue if you ask me and the inductor would be something that is on my mind if I would need to guess. We might have a spare heat pad for you, so just PM me.

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Have you changed the thermal pads between fets and sink at all in 2 years? Cause the ones I have wear out after a while, feels like a short circuit into sink would yield more explosive results tho.

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Thank you for this question because when checking some logs I recognized strange motor temp behaviour.

But first about voltage sag. I have a 12s6p VTC6 pack with maybe 50 cycles.
At a voltage of 46.7V the sag is 2.8V @50A battery current and 6.2V @96A batt.

My soft cut off is set at 38V and the hard cut off at 37V. That means when the battery is at 43V I can hit the hard cut off when using almost 100A from battery, maybe exactly this happened when I experienced the total power loss.

When looking at my logs (FW4+) there are many values jumping around which is strange, I could give many examples. But I never watched the motor temp which I did now.

The motor temp reading is stable but when I start to accelerate the value jumps up and down.

This were a few accelerations on concrete from standstill to 51km/h.

It could be that the soft cut offs happen when the motor is just a bit hot and due to the jumping value the thermal throtteling starts.

I am going to test it now and record a log to see what happens before it’s getting dark. I’ve uploaded the FW4.2 original version and decreased the batt amps from 55A to 50A and increased the motor amps from 80A to 100A :ok_hand:

No never thought about that.