sabvoton controller malfunction

SKYJABE

10 µW
Joined
Aug 13, 2022
Messages
6
evening guys,

i have a mqcon Sabvoton 72150 from 2019 and its been running perfectly well but the phase wires and battery power cables inside were a bit chewed up so i decided to unsolder them and put in 8awg silicone cable instead with colour coordinating heat shrink to keep track of which phase is what colour. finished up and re-assembled everything but now the controller doesnt work right. when i pull the throttle even a little bit it jumps to full power of whatever gear its on then slows down slowly to a cruise type speed but doesn't stop. i thought it was a throttle error so i disconnected the throttle while it was spinning and nothing changed. i then disconnected every port except the throttle, jumped the display and ignition port so it would turn on, and again it wont stop turning. i tried using ebrake regen and it does a really nasty judder but it did stop it. i tried resetting it in mqconnect app but no change. i took it apart and observed the circuit board to see if anything was burnt or wires were in the wrong place and nothing again. is it possible heat damage or logic chip bricked? i touched no other wires during this process, all i did was unsolder phase wires and battery wires and replaced them.
 
Are you certain the wires are hooked up between motor and controller in exactly the same way they used to be, for both phases and halls? If not, you may need to do so for the system to operate the way it did before.
 
absolutely certain, i didnt touch halls at all, everything is exactly as it was i just replaced damaged phase and battery cables. function wise the motor operates fine, all the fets work well and the motor spins as it should but its developed a weird glitch where it doesnt want to stop running. pulling throttle makes the wheel spin up but doesn't stop even after disconnecting the throttle, hall test crashes the controller, ebrake regen stops it dead in its tracks with a nasty judder, the status light is working as it should no error codes, tft display shows the mph its doing but not watts. really scratching my head here...
 
ive had the controller for a while now and removed some pointless cables ages ago such as the alarm cable, i noticed the phase and battery cables had some cuts in them from where the manufacturers had caught them on the housing and just pust some pvc tape around them until i decided to replace the cables completely, i also noticed the busbars from the battery cables werent soldered very well so i flooded a fair bit of solder along both to help reduce resistance, bearing in mind this was years ago and was working perfectly up until now.
 
If you are certain the halls are all working as before, and wired as before, with no connection problems on halls or phases to the controller, then:


It could be ESD (static damage) to the MCU itself. This isn't fixable, as the programmed MCUs aren't available as spares. ESD is easy to cause, and is possible even when using ESD precautions and equipment. (very easy when not doing so) ESD can cause all sorts of wierdness and unpredictable behavior of complex systems, and in some case a complete hard failure of something. ESD-caused failures can happen long after the event that caused them, but are often immediate.

If you're lucky, it's just random alteration of a setting somewhere in the flash. For that event, if you have access to an actual working setup software for your model, and it can read the present settings, you might be able to write all those down in your notes, reset the controller to full factory defaults, and then set it up just for the basic required changes from factory to make it operate your motor. If it then works correctly, you can then set each of the other settings back to where you have them now, one at a time, and see if it continues to work. If not, then whatever the last setting you changed is probably the culprit, and you can change it back and see what happens, and work from there.

If you're not lucky, you'd need a new controller.



It could be completely unrelated to the change(s), but it's more likely that it is.


Another thing to check is the power supply (probably 5V) to the MCU while it's under load, especially while the problem is happening. If you have an oscilloscope you can check for noise on it, that's a good check to do. But if you only have a voltmeter, at least test the voltage on any 5V pads near the MCU that you can, if any are marked. If they aren't, you can check at the PCB pad for the 5v wire that goes out to the halls, and also at the one for the throttle, and anything else that runs from 5v.

If that's ok (5v +/- 0.25v max, and no noise on it if you can check for that), then it isn't the controller "crashing" from that.
 
any preventive measures against ESD and/or common causes of ESD? the way its acting right now i would have guessed being a logic issue being its acting as though its getting a constant low volt throttle signal...uuuuugh new ones cost so much
 
Lots of possible preventive measures (but not effective after the fact):

Properly grounded ESD protection wrist or ankle strap, ensuring enough humidity in the air, not wearing clothing that generates static, etc.

https://www.google.com/search?q=ESD+prevention

Is there actually any voltage on the throttle signal line? (without the throttle connected) If so, it might be fixable if you can find the source of the problem (such as a broken pulldown resistor on that line; this would be between ground and the signal).



SKYJABE said:
any preventive measures against ESD and/or common causes of ESD? the way its acting right now i would have guessed being a logic issue being its acting as though its getting a constant low volt throttle signal...uuuuugh new ones cost so much
 
ok so without the throttle connected the throttle 5v line and ground line measure 4.6v and the signal and ground line measure around 30mv
 
SKYJABE said:
ok so without the throttle connected the throttle 5v line and ground line measure 4.6v and the signal and ground line measure around 30mv

That means that the controller doesn't have a stuck-on throttle input, which probably elimnates the chance of fixing that issue of the controller running the motor even with throttle disconnected. :(
 
alright well since its bricked im gonna strip it again tomorrow and go over it once more and see if i get lucky, thanks for your help
 
Wondering if you managed to resolve the issue.
I bricked my 72200 shorted battery positive with phase wire (forgot to shut of the battery breaker)when removing the motor connections inorder to fit new mudguards.

Anyway I ordered a new controller and have the same issue if I enable hard start works fine if this is disabled though
 
So I am having the exact same problem as skyjabe, but my readings were 5vin goood ground and 5v at the signal??
Sabvoton 72150, QS 273, 72v 40Ah battery…
What does It mean to have a “throttle stuck-on” glitch?
 
If you have 5v at the signal line with the throttle plugged in, but not without it, your ground between throttle and controller is probably broken somewhere.
 
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