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Oscillation and cut out problem with Gotway MSuper V3, ACM, maybe Monster shipped from May 2017 onwards


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11 minutes ago, Rehab1 said:

The Wheel Deal Australia recently posted this on FB. Both the 84v MSuper and ACMs are affected!

ATTENTION  gotway riders that have recently recieved gotway msuper 84v or acm 84v with motor codes starting with 1703 1704 and 1705 there has been a string of cut outs resulting in injurys recently on these models so take care. Will give more info for those effected as i am updated on the situation. So far there have been no 'monsters' effected but take care anyway until we have more information.

Other gotway riders dont worry, it seems to be isolated to the 84v models made since late april.

I recommend protective equipment especially a helmet.

Ride safe and have fun

"Ride safe and have fun". Lovely. I hope the one I'm getting from Jason in the next week or so was made in early April :cry2:

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3 hours ago, Hunka Hunka Burning Love said:

Maybe a sample of each new wheel should be put through rugged drop testing, repeated rough terrain simulation riding, wet weather conditions, etc to help manufacturers identify weaks spots before they end up being a problem.

Hmm, that sounds like what any manufacturer that cared about the quality of the item being manufactured would do! Why is it such a mystery to Gotway??

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2 hours ago, Hunka Hunka Burning Love said:

I think Gotway is just going to review what may have changed during the production batch and see whether there are any weak spots on their end.  They might even go as far as to open up a motor to see if there's any areas of improvement that can be made.  I don't know if any dealers will be sending complete wheels back to them for analysis or not (likely not?) unless they are in China.

Users who have failed wheels likely will get replacement parts starting with control boards as that's the cheapest option followed by motors if they determine that's the issue.   Users likely will need to contact their dealers to get customer service just like with any issue.  Hopefully the dealers will be able to determine the exact cause of failure.  I just hope these are isolated incidents as a mass problem could be very troublesome for everyone.

I'm no electrical engineer or even electrician, so servicing the wheel myself is out of the question.  And all that sounds like it could add a lot of money to the effective cost of a brand new purchase I haven't even received yet, as well as keep my wheel out of my hands for weeks at a time.

I'm pretty unhappy about this.

And I hope it won't be as bad as it sounds.

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7 minutes ago, Dingfelder said:

I'm no electrical engineer or even electrician, so servicing the wheel myself is out of the question.  And all that sounds like it could add a lot of money to the effective cost of a brand new purchase I haven't even received yet, as well as keep my wheel out of my hands for weeks at a time.

I'm pretty unhappy about this.

And I hope it won't be as bad as it sounds.

I've seen lots of fear mongering in the time that I've been following Gotway. To be fair, Gotway doesn't exactly help their cause. But that being said there's an awful lot of happy riders using their Gotway wheels. I think everything will turn out fine.

 A little stoicism will come in handy here. Don't worry about what hasn't happened yet; the future is not preordained. I for one can't wait to get my wheel and enjoy my summertime ripping up my local trails with my new MSuper V3s+ :D

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Well maybe Gotway does do some internal testing.  We just don't know what that testing involves.  I'm just speaking out from my own personal speculation as I'm just a guy with a Ninebot and an opinion so take that for what it's worth.  :whistling:  I've never ridden anything from Gotway or KingSong for that matter.  I bet consumers won't see any price hikes, but they may see delays for affected models if there is a wide spread issue with these batches.  I'd play a wait and see approach to see what the dealers report as they will be on the front lines with this issue.  I'm really curious to find out what the root cause of the problem is.

We see KingSong videos all the time where they ride up and down inclines, steep hills, and crash the wheel down stairs as well as ride around in pools of water.   Maybe Gotway doesn't advertise their testing procedures quite as much.  Maybe @Tilmann who visited their facilities can comment about that as maybe they showed him what testing they normally do?  Even still, testing limited samples may not reveal other problems that only occur in real world situations or what happens over longer usage so it's difficult to say.  I think it would help in future development to put a wheel through some sort of rigorous long term tests rather than depend on consumers to report issues.

Even with cars like the reliable Toyota Camry, I believe they had to recall a bunch due to accelerator pedals getting stuck.  These things happen.  With complex systems that are exposed to harsh conditions, we have to expect some things to go wrong.

Edited by Hunka Hunka Burning Love
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I had temporary moment of insanity last weekend when I was contemplating upgrading to an Msuper v3s+.

I'm happy to report that with this latest news I'm cured... for now :P

I hope to continue to have the strength to resist the urge to volunteer as Gotway  test crash pilot.

 

Edited by Adel
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1 minute ago, Adel said:

I had temporary moment of insanity last weekend when I was contemplating upgrading to an Msuper v3s+.

I'm happy to report that with this latest news I'm cured... for now :P

I hope to continue to have the strength to resist the urge to volunteer as Gotway crash pilot.

 

Buy an ACM V2s+ instead. It is the best all around EUC available. The Gotway gravity well is very strong and hard to resist for long :D

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16 minutes ago, Marty Backe said:

Buy an ACM V2s+ instead. It is the best all around EUC available. The Gotway gravity well is very strong and hard to resist for long :D

I'm just going to gather enough will and stick with my ks16 a little longer. :crying:

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if i'm not mistaken, this plastic sleeve around rehab1's motor wire is also implemented with the same batch of msupers? that means that msupers prior are also, 'hanging by a thread(ed insulation jacket!)

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2 hours ago, Marty Backe said:

I've seen lots of fear mongering in the time that I've been following Gotway. To be fair, Gotway doesn't exactly help their cause. But that being said there's an awful lot of happy riders using their Gotway wheels. I think everything will turn out fine.

 A little stoicism will come in handy here. Don't worry about what hasn't happened yet; the future is not preordained. I for one can't wait to get my wheel and enjoy my summertime ripping up my local trails with my new MSuper V3s+ :D

Well I'm thinking it will be amazing too.  I just hope Gotway didn't do anything stupid.

Especially since I frankly can't afford to get injured.  I have too many responsibilities both at home and at work and some of them are very physical.  I'm okay with small risks, but small or large, I don't want them to be simply unnecessary.

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5 hours ago, esaj said:

I don't recall hearing of the legs snapping off or breaking during riding, usually if there's a hall-sensor problem, it's the connector between the mainboard and the motor cabling, on a couple of occasions a sensor has become loose inside the motor after a hard crash or if the wheel was dropped (not lately, I don't think there have been cases in the last year or so, and even then they were generics?). The stator's not turning, so I'd think only major forces affecting the legs/wiring are bumps and drops, and like you said, there's not much mass on these (mainly the wiring, the sensor itself is glued onto the stator and weighs next to nothing by itself anyway).

Not sure if anyone has ever proven it, but it's been mentioned many times that likely the firmware switches over to "sensorless mode" in higher speeds, and just estimates the rotor position and speed, so the hall-sensors would only be used for start up (to know the starting position of the rotor) and at low speeds. Presumably because of latency and possibly noisy output of the sensor with higher rotational speeds? For a single physical rotation of the tire (one turn), there's multiple "electrical rotations" (ie. switching between the phases) as there are so many poles / magnets in the motors. See for example   https://e2e.ti.com/blogs_/b/motordrivecontrol/archive/2014/05/23/mind-spinning-possibilities-hall-effect-sensor-bandwidth-in-bldc-motors   (Do note that they speak of a motor with much lower amount of poles than the usual wheel-motor, and probably their own hall-sensor, to which this appears be marketing material for ;) is likely faster/has higher bandwidth than the cheaper ones)

Very interesting theory about "sensorless mode". That would make me feel better (not that I worry much about it) when traveling fast. Even if a sensor were to fail the wheel wouldn't stop immediately. Let's hope this is the case.

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20 minutes ago, Marty Backe said:

Very interesting theory about "sensorless mode". That would make me feel better (not that I worry much about it) when traveling fast. Even if a sensor were to fail the wheel wouldn't stop immediately. Let's hope this is the case.

Yeah, I think it was discussed in the (custom) Firmware-thread in the Mods-section or elsewhere in the forums... I don't know if it's true or not, it's all speculation since no-one knows how the firmware of each wheel actually works in a detailed level, and the manufacturers are unlikely to reveal much technical details. Some things can be deduced and partially backed just by inspecting the electronics on the boards (like that they likely use FOC or such, as BLDC-trapezoidal control wouldn't require current sensing to my knowledge, and the motors appear to be PMSM's anyway), but lots of it is just guesswork.

Edited by esaj
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  • esaj changed the title to Oscillation and cut out problem with Gotway MSuper V3, ACM, maybe Monster shipped from May 2017 onwards
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