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Ninebot random shutoff :(


DrOne

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Hmm.. that video does not show a random shut-off... it shows him drop something in front of the wheel, it jams, and stops.

Might not want to show that video to a lawyer... not theirs.

He drops it from his left hand, whatever it was... Foam-rubber thing... Cup-holder, wrist guard, trash... You see it get kicked-out as the wheel reverses to eject it.

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Hope you have a fast and full recovery!

Since i ride a 9B myself, i am quite interessted in the different reasons he could fail. Mainly as self protection and maybe as decissionhelper for my next EUC, once i upgrade...

14 hours ago, HonestPizza said:

In this video you can clearly hear the unit rev to a really high RPM before shutting off.)

As you wrote that the unit revved up really high - then it is the "normal" behaviour of any EUC to shut down. Same as if you lift it up, it will rev up until max rpm/speed is reached and then turn off. 

Now the interesting question (at least for me) is: how could it rev up like this?! For now i just could think of three possibilities:

There is no powertransmission in this kind of EUC, so if the motor revs up the wheel rim has to rev up:

- There was something (piece of tarmac with very low friction, oil, a pebble, leave or whatever) that caused the tire to loose friction. Once the static friction between the tarmac and tire was lost, by spinning up the tire/tarmax stayed in the state of "sliding friction" and kept reving up without accelerating. Since trying to accelerate failed, the EUC puts even more power to the motor and so kept spinning up until shutoff at max rpm-> feels like an overlean/shutoff as the wheel could not accelerate/balance anymore. 

In the video it seems (looking at it in slow motion) that you lift your right arm just before/in the moment the wheel starts to tilt forward? I assume this was exactly the moment the EUC started revving up?

- The tire lost the friction to the wheel rim. But why and how should this happen in the mid of driving? There should/could be tracks on the rim/tire/tube which could give a hint?

If one can exclude that the wheel rim revved up, only something like this could have happend:?

- The revving up never happend - it just sounded like. Somehow the controller lost sync with the motor state, the "control loop" did not recover and the "power pulses" he sent to the motor made him sound like revving up. (Imho this seems quite a stretch... )

Btw.: Regarding you question maybe the thread link in your other thread helps you...

 

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16 hours ago, HonestPizza said:

The more research I do, the more I think I can attribute the revving to simply a higher pitched sound as a result of the new firmware.

You could look at this with any spectrum analyzer (maybe already in your video editing software, or else in progs like Demo Version of Wavepad). You should see (from time to time) a peak at 8kHz, which is the frequency of the PWM Pulses with the new firmware - and then the change with your accident.

16 hours ago, HonestPizza said:

The road was perfectly with no oil or debris. We'd ridden over that exact spot dozens of times throughout the day without issue.

Also with small debris it was never a problem (for me and my bot) till now. Just a small "glitch" slightly noticable and everything went on normal... *knockingonwood*

So all three of my possibilities can be excluded ;) I am already looking forward to the outcome of your case and some interesting insights...

16 hours ago, HonestPizza said:

Thanks for the link in the other thread, by the way. I am going to dig in there and see what can be done. Unfortunately, it seems that Ninebot failed ti implement an event log.

Yes. And if a log is implemented it will be very hard to figure it out just by guessing... ;(

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2 hours ago, chriscalandro said:

When you are the only one to have this issue on this firmware, it is NOT reasonable to suspect that is the issue. 

The wheel cannot "rev" without going faster. Everyone that saw the video, as well as you said that is what happened. 

When there have been a lot of reports of shutoffs on many different versions of the firmware, it's very hard to rule out firmware as the cause of an accident. I agree it's not good to rush to judgement without evidence though. That's why it would be handy to have more data recording on these wheels like speed, battery level, current draw. All we have is a video and all the important stuff happens in about a dozen frames.

I think the "rev" is more likely the sound of the motor pitch changing as a result of it shutting off, being overpowered, or somehow getting out of sync. It's hard to describe unless you've experienced it, but both times when I've fallen at high speed I've heard the motor pitch change a split second before that. 

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Major ouch! Watching in slow motion, it is interesting to me how the human body reacts when it is falling... our instincts and evolution have made our wrists and collar bone targets for "breaking" a fall so that we don't injure something more serious like a spine or skull. It's a toss-up as to whether wrists or shoulder will take the fall, depending on circumstances and instincts. In this case, I guess the collar bone has done its job, which is to break so that nothing else breaks.

As he is falling, you can see arms reach out towards the floor... but just before impacting (and probably breaking his wrists), you see his arms fold under him and he lands on his shoulder, thus taking out the collar bone. The thing is, I bet if he was wearing wrist guards, he'd be more likely to carry on with the arms-out landing, instead of landing on the shoulder. 

Conclusion: Can't control a faulty EUC but one can control wearing protective gear and this video convinces me to always always wear wrist guards.

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36 minutes ago, glorat said:

Conclusion: Can't control a faulty EUC but one can control wearing protective gear and this video convinces me to always always wear wrist guards.

Don't forget the elbow and knee guards. There are soft types that are not so dorky looking like the Triple Eight Exoskins.

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I have just seen a video presentation of the new Airwheel S6. Apparently, it features a dual BMS and dual motherboard in order to ensure safe slowdown and stop in case of a fried PCB. I can not imagine that our EUCs will not follow the trend.

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18 minutes ago, Gil said:

I have just seen a video presentation of the new Airwheel S6. Apparently, it features a dual BMS and dual motherboard in order to ensure safe slowdown and stop in case of a fried PCB. I can not imagine that our EUCs will not follow the trend.

That sounded good, until I saw that the S6 is a Segway-type vehicle with a saddle... :D

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  • 2 weeks later...

Hey guys, I'm new to this forum.
I came across this forum because I was searching for shutdown issues related to the 9B1E+. A very similar thing happened to me a few days ago where i was cruising at a relatively moderate speed when my bot just shutdown on me. I fractured my left wrist and elbow. I had just upgraded to the most recent firmware. I'm curious if there is a way to reset this back to the original. Does anyone know if this is possible? 
 

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Sorry to hear about your fall. Hope you recover fast. After reading so many posts about firmware upgrade disasters, I kept mine at 1.2.2. 

Ninebots are known for firmware failures. Wish you had been to this forum before the incident. Were you wearing any protection at all like helmet and elbow pads? 

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Maybe admin can make a petition. Where we can sign using our email address and actual name to petition ninebot to make downgrade choice to 1.2.2.  When someone gets hurt, they can use this petition, as a legal defense tool. More and more people getting hurt on 1.3.5 after upgrade.

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10 hours ago, chriscalandro said:

 

@Gil The segway that was available in 2001 was redundant.  This is not a new groundbreaking technology.

Ninebot did implement redundancy too in their 9 and Elite right from the start. Thing is - elite is twice the weight of ninebot one...

But on a positive note - the rumor has it that new 14" version will get double battery pack. So at least some problems will be avoided..

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  • 1 month later...
On 1/18/2016 at 4:23 PM, AceFace said:

I had my first shut off at the weekend. I accelerated gradually to test out the top speed and the wheel simply stopped dead at full pelt (with no tilt-back).   I went down hard, face first but tucked in my head to save myself with a judo roll, however really bruised my palms and elbow in the impact.

My battery was at least 50% charged, so this came as quite a shock.  I'm quite nervous now of approaching the top end of the speed range in case it happens again - this time lucky, next time I could end up with broken bones!

If this is to be expected, everyone should learn to judo roll - probably the only thing that will save you in a fall at 20kph.

(I'm running 1.3.0)

50%? I am starting to think that you should never go below 75%.  My Ninebotone E+ felt weak at that level of power.

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9 hours ago, steve454 said:

50%? I am starting to think that you should never go below 75%.  My Ninebotone E+ felt weak at that level of power.

You can't be serious? How much do you weight?

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13 hours ago, Vik's said:

You can't be serious? How much do you weight?

210 with gear and I am 6' 3" which doesn't help.  But so far am only riding on grass and dirt which causes a lot of drag.  I fell off my TG T3 132watt twice on pavement while learning and hurt two fingers.  I know when I start riding sidewalks again the motor will have much less strain.

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8 minutes ago, Vik's said:

@steve454 Hmm... 210 is still way under the max load of 265. Would it help to get higher tire pressure? And yeah, asphalt/tarmac is much easier on the motor.

Thanks,@Vik's, just checked pressure it was down to about 20psi.  I picked up the Ninebot on March 5th and the dealer put it at 45psi.  I guess I will be checking pressure more often.  I am sure that will make a big difference.  Sometimes you forget the little things, but that is what makes this forum so good, lots of good info.

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Concerning little things:

  • check the pressure at least once per week
  • you can inject sealant in the air tube to limit the air leakage and to be somewhat protected against punctures
  • although many people say it is useless, I could notice that air is getting out when the tire is brutally compressed (bumps, curbs) if you have no valve cap

I bought recently this and this and checking the pressure has become a pleasure.

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