New Dual FSESC 6.6 Weird cutouts at high amp settings?

Previously I had a Dual FSESC 6.6 that had a weird issue where one side became unresponsive after working fine and loop key disconnecting after a ride. I bought a new one and soldered it directly back into the enclosure. I put my settings back how I like them as close as I could from memory.

My settings are usually as follows(I added a picture as well)
-0.0 Second positive ramp time(I like it snappy, could this cause issues? Even if I keep default settings it will still cut out when riding on hard acceleration)
-85A Motor Current Max (I know its high, typically I ride on a softer setting, only kicking it up for some short hard accelerations)
-100A Battery Current Max (10P 30Q should handle it especially since I only do short bursts and probably never reach that in battery amps)


My problem is that the board cuts out on hard acceleration when in the high setting. Placing it in lower settings such as medium or low (75% and 50% motor max) work without any issues. I added a video that shows the before and after. You can see in the first clip with my original chip, the board is very snappy and immediately hits top speed when flicking the throttle. Then in the next clip you can see the board working fine on a low setting and then cutting out on the higher setting. I can be in the high setting and slowly move it up to speed, but trying to go full throttle if not already moving fast will usually kill it for a second. Lastly, a video of the chip itself working fine in low settings and then cutting out in high settings. Sometimes one vesc will cut out and the other will run, this is a bit more rare though.

It’s weird as I believe I have all the same old settings. If you know any that may cause this, please let me know. I can climb hills and drive all around perfectly fine on low motor amp settings, but its really killing me to not be able to blast up a hill or take off on smooth streets. Any ideas on how to get back my high power?

tl;dr: - Board cuts out on high amp settings despite working on such settings in the past without issue. I believe my amp settings should be high enough to not overcurrent fault. (85A Motor:100A Battery)

Check fault codes.
My guess is you hit the ABS overcurrent when hard accelerating. In that case your esc will drop out for 1-2seconds till it reboots and you back up again.
The ramping does affect that in a way, but is not the main cause in my experience.
What you can do if it’s really caused by ABS overcurrent is to set the Absolute max current value up. Try something between 180-220A.

With this said, I would double check all solder joints and connectors as well as the capacitors first. If there is something lose or you find a cold solder joint it might be causing the drop outs.

1 Like

I am using XT90 connectors with good solder joints as phase connectors. This should be okay right?

I’ll definitely try some much higher ABS current and fault codes, thank you for that.

1 Like

Just double check it if you want to be sure. Could also be from the esc side solder connections. Flipsky QC isn’t what I would call on point :sweat_smile:

Set ramp up/down at 0.1 or higher, your legs won’t cry. Also set absolute max at the, well, absolute max it can go, on all sides individually.
Also battery amps should not be higher than motor amps. In theory you will never exceed the motor amps value anyway
Also get a bluetooth module and see what’s actually going on

1 Like

Even at ABS current set to 1000 on no limit firmware, it still happens. I set ABS current to something very low like 10A and the lights and motor symptoms are all the same. It cuts out the same way but even on low settings. Seems odd that even 1000A ABS current doesn’t fix it, but setting it to 10A ABS produces the symptoms as before.

Maybe a good alternative in the future

If you run FOC you could try under FOC advanced settings to set the high current sampling to true. Maybe that might help.
Just guessing here, but it’s worth a try.

No difference trying that setting. I was wondering if the diode you were speaking of here in your comment happens to be on the Vesc battery mains, and if so, what type of diode?

I hope I’m not pestering you too much, but I’m thinking that a diode might be what I need, and you seem to have known about that issue on other chips… I notice that some newer Flipsky Dual 6.6’s online do have a diode there. Maybe I should experiment and add my own…

I‘m not an micro electronic expert and I do not know the Flipsky schematics and pcb layout, so I unfortunately can’t help you there.
Maybe @Gamer43 can help you here.
He seems to always know why and where escs have their week spots.

That’s a brownout or watchdog reset.

What are the details on your battery (BMS)? How long have you been using it?

Did you update firmware or otherwise change the firmware on them?

10P 30Q can do 100A factory new, but not necessarily if worn down.

And yes the high amp settings do have something because the current controllers on VESC tend to overshoot.

Also double check the connection with the new loopkey, if the resistance of the connection is higher than previously, it can cause fluctuations in the voltage the ESC sees and might cause problems in the algorithm.

Battery is a 10S10P 30Q about 1 year old with maybe 50 cycles at most as I don’t need to charge often with that amount of range. BMS is bypassed for charge only.

Firmware is the same I was using on my old chip that worked without these issues. I also temporarily tested the no limit firmware to set ABS current to 1000A to try and see if that was setting it off.

If it helps, when the chip cuts out, it will also disconnect from the computer. I have to reconnect and never find any faults in the terminal which is upsetting.

If I put the board up against a wall and slowly raise the amperage(throttle) I can get to about 70A before it kills it, but if I try to do it quickly it will cut out sooner not even graphing it in Vesc tool to see what levels it was dealing with at failure.

Here’s a picture of one of my buddies who actually had the diode I was talking about versus one of mine. You don’t think it will solve the issue?

I’m also wondering if it could be the xt90 connectors, I thought it was okay to use them as they were pretty much the same as using any 4.5mm bullet connector but in a different connector shape (basically). They are anti spark but I don’t think that should cause any issues, right?
image

Just realized I replied to the thread and not you. Here’s a notification just in case.

1 Like

So the only thing you said that has changed between when it didnt have this problem and now is the connector.

Have you tried it with a different or the original connector?

The diode on the input has no effect.

It worked on my old Dual FSESC 6.6 before it suddenly became unresponsive on one side.

Bought a new one and decided rather than directly soldering motors to the vesc, I’d use 3 XT90 connectors for the 6 phase wires. Would allow me to swap a new motor in easier.

After setting it up with the same settings to the best of my memory(I’m pretty sure they’re all the same), it seems to always cut out. I’m fairly certain the solder joints are not cold as I use a 350W solder gun, but at this point I am pretty desperate. I might try resoldering everything in a week or even bypassing the xt90 and going for my old hardwired in setup… still wondering if maybe it’s something wrong with the Vesc or my configuration.

Forgot to reply specifically to you again.

Ok, I think understand now.

So this ESC that currently has the cutout issue, always had this issue, correct?
You had a different ESC that did not have this issue, but stopped working for whatever reason and that is why you got this new ESC that does have this issue.

This actually raises a few more questions. How old was the previous dual ESC, and did you ever update the firmware on it?

1 Like

Correct, this new ESC has always had the issue. I have updated the firmware, and have even updated it to no limit firmware to experiment there.

I had another one in the past, same model, which seemed to have died for no reason. On this old one, I had just got back from a normal ride, hard accelerations on hills and some slower cruising. Pulled back home, loop key disconnected it, and threw it on the charger. Come back next day and only one motor ran… everything I tried could not get connection to the dead side. CAN, USB and receiver plugged in yielded nothing.

Heres the thread (Dual FSESC6.6 Mini Half Working)

This new ESC that I have will always cut out if it draws more than that ~70A. On the medium settings, board performs perfectly normal, I can full throttle it, hard break, whatever really. Just went on a ~10Mile ride Wednesday all in medium no issues. If I did however kick it into high and try to drive on grass or even just trying to punch the acceleration, it would cut out within half a second.

Maybe reinstall VESC Tool is worth a shot… Ill update the thread with how it goes. Still really puzzling how it has all the symptoms of ABS current fault, yet ABS is set to 1000A.

Did you ever update firmware on the old one?

Overcurrent fault is not the issue here.
The issue is either the ESC is losing power or there’s a firmware bug causing the ESC to reset itself.
I need to know what firmware version the old one was using (just give a rough date of the last time you might have updated firmware).

The old one might still be salvageable too. It looks like either the MCU is dead or firmware corrupted. Idk why but firmware corruption is a thing on these.

There are plenty of guys here who can do an MCU replacement.

THE MYSTERY IS SOLVED…

Today I redownloaded VESC tool, updated the firmware, reprogrammed the ESCs and charged the board 100%.

Fixed all issues! Well, not really…

I put a good 10 miles on it before I noticed that hard acceleration caused it to seem to drop battery level on my remote. I thought this was a little sag on heavy draw and kept riding. Then I noticed if I did hard acceleration, the motors began making that very distinct wobbly noise of low battery soft cutoff. Odd as I know the boards full range is around 40-50 miles depending on riding conditions. Every time I check the remote its reporting 75% so I think nothing of it. Then the cutouts begin on hard acceleration. throw it in medium and head home. Battery voltage is pretty decent, 37.5 on 10S. Open it up and start testing balance leads and one group is at 1V.

The board was cutting out as the low voltage cutoff was being hit every time. The board had been in storage for a bit while I replaced this, and the BMS I have been suspicious about in the past. Combining the two, I have a very low voltage p group that would pretty much short out whenever I accelerated too hard.

Thank you for all the help. It seems that I have some battery work to do.

3 Likes