Diagnosing esc failed start up

[Chapinb]

Long post. Will be attempting to warrantee through hobbywing (sent prayers!). I'm looking for any insight as to what is going on.

Have a surpass 4274 1500 motor, 1 month old, not abused max6 esc on 6s. It most often happens initial turn on, but will also happen every 5 min or so during running. The esc will turn off and reinitialize. The telemetry on the radio registers low receiver voltage, which is different than if I turn off or unplug the esc. Will do this with multiple batteries, without the receiver, servo, fans or anything else connected to it. Is not water or cold related. Is an intermittent issues that will prevent startup all together or work for 20 min, is a dice roll. Power delivery, temps are all good when it works. Once every dozen or so failed start up, the esc goes dead - power button and unplugging lipo does nothing to bring it back to life. Capacitors need to be discharged then lights come back on an we are off again. If I disconnect 1 or motor wires, it starts reliably every time. Replacing that wire in usually works, sometimes will restart again. Multiple motors will cause the same issue, so it's esc related I believe.

Thought on failure mode? You can hear a relay clicking when it restarts.

 

[RCbuzz]

Long post. Will be attempting to warrantee through hobbywing (sent prayers!). I'm looking for any insight as to what is going on.

Have a surpass 4274 1500 motor, 1 month old, not abused max6 esc on 6s. It most often happens initial turn on, but will also happen every 5 min or so during running. The esc will turn off and reinitialize. The telemetry on the radio registers low receiver voltage, which is different than if I turn off or unplug the esc. Will do this with multiple batteries, without the receiver, servo, fans or anything else connected to it. Is not water or cold related. Is an intermittent issues that will prevent startup all together or work for 20 min, is a dice roll. Power delivery, temps are all good when it works. Once every dozen or so failed start up, the esc goes dead - power button and unplugging lipo does nothing to bring it back to life. Capacitors need to be discharged then lights come back on an we are off again. If I disconnect 1 or motor wires, it starts reliably every time. Replacing that wire in usually works, sometimes will restart again. Multiple motors will cause the same issue, so it's esc related I believe.

Thought on failure mode? You can hear a relay clicking when it restarts.

Do you have a different motor you can try? I have heard of servos going bad causing drains or faults on the ESC's BEC.

When stuff like this happens I like to put the ESC into a different car. If it runs right it can help with troubleshooting.

 

[Chapinb]

Happens with no receiver or servo attached and with multiple other motors.

 

[RCbuzz]

Sounds like there is a defect somewhere in that esc. Power connectors look good? Does it do it with difference cell batteries?

 

[Chapinb]

Same fail on 4s. All connectors are solid as far as I can tell. If it was something loose, I'd think it would turn off while driving. Usually when it restarts, it's relatively slow or stopped, never when under full power.
It's not acting like it's loosing power via lipo or turning off from switch. Seems more like it's rebooting.

Only happens when all 3 motor wires are attached. When only, 2 still go get a chime. If 1 or 0, it also boots fine.

 

[RCbuzz]

Did you try the rig with a different esc?

 

[Chapinb]

Basically. It's attached to the same chassis, but with different motors, lipos and no receiver.
It's not arming from lack of receiver input, it never gets that far. Dosent get to the motor voltage chime.

 

[RCbuzz]

You mentioned a different servo as well? Sounds like you covered just about everything.

 

[Chapinb]

Didn't try a different servo, but did unplug it and all fans before removing the receiver all together. Since tried another receiver (no servo) with same result. Rebooting before initializing.

I'm positive the esc is faulty. Hoping to be proved wrong as any other option is cheaper/easier. If I'm right, I'm still hoping to find out why, or if I did anything.

Rma request filed, will see what HW says.

Just boggles my mind sometimes it works, and amazing at that. Smooth, powerful. Jumps, bad landings and it keeps going. Then Ill stop for a car or dog, it decides to reboot over and over, eventually working again. Like somethings loose, but fails only when stationary.

 

[RCbuzz]

Yea thats a strange one. We have seen multiple servo failures causing brown outs, low or shorted BEC voltage.

 

[Chapinb]

Spent some time playing with a voltage supply with possibly some info. Lower voltages seem to work better. It hasent failed startup on 3s voltage. 4s, maybe 5% fail. 8s, 50% fail with a migh higher likelihood of, for lack of better term, temporary bricking it. Comes back after discharging the caps.

Interestingly I can't get it to register 5s or 7s. Presumably so it dosent mis read the cell voltage?

 

[RCbuzz]

BEC set to 6v?

 

[Chapinb]

BEC set to 6v?

I was just playing with that! At 6v, no fails on 8s. Bumped to 7.2v, had 1 failure in 10 tries. Back to 8.4v and started failing again on the regular. I bumped bec to 8.4v since new, a few dozen packs before it started this.

6v and stress tested the servo, stayed on. So maybe I have a functional, but broken esc again?

So something to do with the bec failing? I had an inkling it might be related with the receiver throwing a low input voltage error before esc rebooting.

 

[RCbuzz]

Hmm.. i would try a different servo(not a high current one) and make sure your receiver is ok with 7.4volt and 8.6volts.

 

[Chapinb]

Happens with out anything external on bec, so it's not the servo or receiver causing it. But I did stiffen the servo saver spring some a few packs before this started.
Tis a 30kg amazon servo, so nothing high test. Is only rated 7.2v and was feeding 8.4, so can't say it wasn't the servo that caused it with the saver spring. Even at 8.4v, stall torque is 5-6 amps, below the 8 amps the esc is rated for. The servo isn't at stall though, it can still overpower the saver.
I seriously doubt the servo is the cause, or if it was, I had a bad bec beforehand amd the servo just gave it a shove. Servo and receiver all work as expected for what it's worth.

 

[RCbuzz]

I am usually quite cautious with internal BEC's. Overloading them (or shorts) can cause brownouts, BEC overload, or even catastrophic failure.

Even my lights on ESC's I care about are fused .

Hard to say what happened but if it's doing the restart thing with nothing connected it's hard to say what's up. Silly question, esc fan ok?

 

[Chapinb]

Left it unplugged for awhile when I was at a total loss for why. Once I discovered leaving a motor lead off, I plugged it back in since it was easier to tell when it rebooted. Tried unplugging again for the heck of it, still failed.

Thank you for following the thread. Without your response I probably wouldn't have kept fiddling and testing.

 

[razorrc]

You know what you’re doing, which leaves only one answer —

 

[hobo]

Left it unplugged for awhile when I was at a total loss for why. Once I discovered leaving a motor lead off, I plugged it back in since it was easier to tell when it rebooted. Tried unplugging again for the heck of it, still failed.

Thank you for following the thread. Without your response I probably wouldn't have kept fiddling and testing.

only time my firma 150a esc has done that was with the stock firma servo once that servo was changed all was fine. like said above yours is caput

 

[GeckoDragon]

I know you said not abused, but that's a pretty subjective term when it comes to RC. Did you ever run it in wet, dirt, or muddy conditions? All it would take is a tiny bit of contaminants or corrosion on the PCB to cause occasional arcing, which could cause a reboot. Big jumps or heavy offroading (lots of vibration) could also possibly have started to break the strands of a signal wire, with the reboot happening whenever the broken wire strands briefly pull away from each other before reestablishing a mechanical connection