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Brands with / without unexpected shutdowns (new buyers look here)


KaleOsaurusRex

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From my experience I've found Airwheels, Firstwheels and Rockwheels will shut off as soon as you ask for too much power (jumping off a curb, riding over an unexpected bump or pot hole).  This is dangerous and can cause serious injuries.  Two friends of mine came off their Rockwheels at high speeds because of this issue and they got very bruised up.

Solowheel, newer models of IPS and Ninebot do not shut off and are a lot safer.  On quite a few occasions I have gone through pot holes I hadn't seen at top speed on my Ninebot E, I overpowered it, it started dipping forwards as if to drop me, but it kept applying power which just managed to pick me back up again and save me from a bad accident. 

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The Inmotion is also very good and does not shut off, only problem is every time there is a high power demand it shouts 'Be careful, slow down', which gets very annoying and can be embarrassing when in a crowd.

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I wouldn't necessarily say the high torque M18 is safer but it is more suitable for my weight and the hilly terrain I ride it over.

It will still fail to keep you upright if you try to accelerate too quickly at high speed on an uphill climb.

Having not ridden the other two versions I'm in no real position to make a comparison.

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I don't know if it's really a factor, but I thought that maybe the reason for the mainboard cutoff was to prevent the mainboard from breaking due to high temperatures/currents. To produce the same power (watts) with lower voltage, you need higher current, ie P = U*I, I = P/U:

500W of power @ 67V = 500W / 67V = about 7.46A

500W of power @ 60V = 500W / 60V = about 8.33A

500W of power @ 56V = 500W / 56V = about 8.93A

500W of power @ 52V = 500W / 52V = about 9.62A

etc., higher current for same wattage at lower voltage. If the mosfets were to burn, you'd faceplant anyway, plus the mainboard would break.

​Esaj, here is the example of a generic X3 (I have close-up pictures of Gotway's mainboard too) : http://googledrive.com/host/0BxMfsstZ1EMcfkYzSzFmTVRHZGg5UzUwQjlqbk1wTzJTNjJiMG9wRWRKdVZlMnlEbGVqZkE/mainboard_x3.JPG

You can see the references and look up the mosfets' documentation (p75NF75 for example). You will see even the cheapeast of them can withstand 80A continuous current (320A pulsed current, enough to kill a cow), way higher than the even the highest currents in a monowheel. So your hints about maximum current & power are legitimate but not justified with actual mosfets (20 years ago, such mosfets would be prohibitive but nowadays, they are widely available and dirt cheap).
Even if they were true, there is still no reason to shutdown the power, suffice to keep it to constant or reduced levels to maintain maximum temperature equilibrium, it would still be way less hasardous to the rider than a cut off !!!
The only nearly pausible justification I can see for a cutoff at high speed is overvoltage when braking violently, because the motor acts as a generator. If the power stage is not correctly voltage-rated, the overvoltage may grill the drivers and cause a shoot-through of the Mosfets half-bridge. But it is not at all a problem on a carefully designed mainboard (eg the Firewheel), even more so with a beefy battery to absorb the regenerative braking voltage surge. But then again, suffice to keep the speed under the allowable values and let the rider sort it out, no need to cut off.

The more I think about it, the more I find this cut-off crazy, vicious and unjustifiable. If I am in charge of the payroll of the team responsible for such craziness, I would ask serious questions and demand serious answers. And seriously kick asses.

 

 

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Yes, these solutions might add some cost. Yes, the solution might reduce the usable range of a given battery size. 

Objectively, no and no. Implementing warning by tilt-back or vibration requires some lines of codes and costs $0, hell even the cheapest of the cheapeast generic wheels have it. NOT cutting  off the power requires removing the f.cking r.tarded cutoff function, so it costs less than 0$. Removing the cutoff mosfets from the BMS will even let the manufacturer gain $2 or $3 (see the Gotway's BMS not populated with those mosfets). And rolling at very low speed with shaking (Ninebot) and severe tilt-back (generic X3), leaving the rider no option accept a climb down will prevent a overdischarge, no need of a cut off.

We are not not spoiled brats demanding the impossible. We have legitimate, reasonned and reasonnable requests.

Again, I insist, there no reason to attenuate or compromise our points and there is no reason not to implement them.

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This afternoon, coming back home, I had the Gotway 340 Wh battery almost empty (I wanted to check they shipped me really a 340Wh battery).

It was beeping 2 beeps all along my last 1km, while I was riding at ... 6km/h. I was making as much noise as a big trash truck in reverse, hellishly embarassing and quite frightening after my last take-off.

Come on Gotway, what a joke !  Why don't you let me ride silently like with any wheel and simply tilt back to let me know you're done.

Oh another thing that erodes my confidence in Gotway : I got a total of

  •  31.97km distance according the Android app (not bad for a full charge).
  •  31.82 km according to the bike computer, with 0.1% accuracy.

So the Gotway's revolution counter is correct, since its odometer give a trustfull number.

But every GW user knows that the GW speedometer is inflated by about 3km/h, in the android app, in the beep thresholds, ect.

So I contend I have firm evidence Gotway is cheating on the displayed speeds for promotional purposes. They keep saying in their commercials the beeps are at 23km/h but in fact, I have beeps at 20km/h (testified by my trustworthy bike computer).

Come on Gotway, too much jokes, you are NOT funny !

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​Esaj, here is the example of a generic X3 (I have close-up pictures of Gotway's mainboard too) : http://googledrive.com/host/0BxMfsstZ1EMcfkYzSzFmTVRHZGg5UzUwQjlqbk1wTzJTNjJiMG9wRWRKdVZlMnlEbGVqZkE/mainboard_x3.JPG

You can see the references and look up the mosfets' documentation (p75NF75 for example). You will see even the cheapeast of them can withstand 80A continuous current (320A pulsed current, enough to kill a cow), way higher than the even the highest currents in a monowheel. So your hints about maximum current & power are legitimate but not justified with actual mosfets (20 years ago, such mosfets would be prohibitive but nowadays, they are widely available and dirt cheap).

Ok, so there really is no reason for the mainboard cut out... hopefully they'll get rid of it too :)

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Without a tactile feedback mechanism (pedal-tilt-back), there is invariably a risk that a rider can overpower the battery, circuit-board, motor, wires whatever...

Engineering capabilities not infinite, I agree that manufacturers need to be taking a continuous improvement approach to Wheel safety, but at the same time, the buying public ought to be aware that a 132Wh/350W Airwheel/generic is not going to support a 120kg rider, regardless of what the manufacturer proclaims. Yes, shunting could improve the situation of when the Wheel give's out, but I see a partial consequence of this is that the load on the battery-pack could surpass the power rating, increasing the risk of a premature catastrophic battery-failure, or degraded performance.

In my books I see safety as:

  1. Sensible pedal-tilt-back programming 
  2. Enough surplus power to support a rider's weight that the model claims to
  3. A top-speed where a rider can run-off if necessary (perhaps with an override control after signing disclaimers & insurance) 
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Thanks for this initiative! It's a great compilation of important aspects normaly no rider could easily gather until it happened...

This should give the manufacturers important feedback, too - unless they don't care about their custumers ;)

If you look at the "downhill riding" thread, imho thats an important point regarding safety,too:

- if the wheel just gets faster, until it cannot balance the driver anymore

- just cuts off

- overloads the battery back

- or burns the excess power in resistors with heatsinks after the battery pack is full and nicely drives downhill all the time

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Hi guys.  I'm new on here, and just bought a MonoRover R3.  I emailed them regarding this thread, and they replied promptly saying these issues are fixed in the R3, which is a relief to me :)  I guess this can be added to the list of fixed scooters.

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Hi guys.  I'm new on here, and just bought a MonoRover R3.  I emailed them regarding this thread, and they replied promptly saying these issues are fixed in the R3, which is a relief to me :)  I guess this can be added to the list of fixed scooters.

Thank you Luke for your feedback.

If I was you, I wouldn't trust them without verifying. Most of time, they'll tell you what you want to hear instead of "I don't know".

​Ask them HOW it has been fixed. Since when, what's the serial number of fixed and non fixed versions...

If you have no credible response, it smells a rat. If you can take picture of the battery pack, I can tell you if it's fixed or not.

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Thank you Luke for your feedback.

If I was you, I wouldn't trust them without verifying. Most of time, they'll tell you what you want to hear instead of "I don't know".

Ask them HOW it has been fixed. Since when, what's the serial number of fixed and non fixed versions...

If you have no credible response, it smells a rat. If you can take picture of the battery pack, I can tell you if it's fixed or not.

Actually, I did email them again for verification and still waiting for reply.  In the end I cancelled the order and now waiting for NineBot One E+ instead ;-)

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Uh.. 'Bless' you guys for providing this information.   Based on the information you are posting, on Saturday July 4th I must have had a mainboard shutdown on my AirWheel X8.  

In North Carolina it was anything but cold that day.  I had GPS-ed my rides so I know I rode more than 4.5 miles on my first ride.  On my second ride I got up to 2.25 miles with 1 battery light remaining after the fall.  I was riding a fairly hilly park that day.  I was riding confidently, meaning I was making the thing beep all over the place.  Finally I was going up a fairly steep (but short) grade (though not one I hadn't done before) and the machine just threw me.  It acted as if it were not turned on anymore - however, it did not shut itself off - and beeped the safety warning after it had toppled.  (It was still on as I picked myself up off the asphalt.) (Slowly.)  [I do believe I was indeed accelerating up a fairly steep incline at the time.]

On July 4th in NC, the last thing I wanted to do was go to the Urgent Care, but I did indeed go, as I felt as if I had possibly broken some ribs.  Thankfully the X-Rays showed that they weren't broken.  

Today, 4 days later, I'm starting to feel well enough to try to ride again.  I rode 2 miles but slowly and on more level ground.

I love to ride, and I am riding very confidently (at least before the accident.)  I am considering replacing the AirWheel X8 with a Ninebot One E+.   Better range equals generally higher battery levels on average.  Is that a good move?

At 55 years of age, I cannot afford too many injuries of this nature.  I was lucky. 

Ah.  Based on my personal experience, the idea of 'run off' of a failing unit might be a myth.  On an epic failure, one usually hits the ground before the urge to run off is activated.  But maybe that is just an old man talking.  Your milage may vary from mine. 

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First of all I am glad to hear that you are not seriously injured!

I am not significantly younger, but could manage to "run off" my failing X3 once or twice. However, that was at a relative low speed and an uphill ride. I am also about to upgrade to a more reliable EU and consider the Ninebot One E+ too.

But if I may say and I do not want to put too fine a point on it, the beeping is a safety feature. It is not rather unwise riding the EU making it beep all over the place?

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@dpong I think we all have learned this the hard way so don't feel too bad about it. Avoid running the battery down to nearly the end. When the battery is low ride it very gently and be prepared just in case it starts to misbehave. The more you ride, the more complacent you can get.

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Sorry to hear what happened to you dpong, I hope you are recovering fast.

Airwheel is notorious for causing BMS cutoff accidents, as long as they don't do anything against it, it's a wheel to avoid. But I don't think they have implemented a mainboard cutoff. Gotway has !

A fall like this can be caused by two things different, but not always easily distinguisable the first (or second, even third) time it happens

  1. because you lean forward too much and lose balance. That's something the user can avoid, and that the wheel can't do much about.
  2. because the wheel shuts down power. That's something utterly stupid.

I persist in saying a power cutoff during a ride, by the BMS (lot and lot of brands) or by the mainboard (Gotway)  is really stupid and dangerous and there is absolutely no technical reason to do it or justify it, none ! A French forumer has recently had a battery problem on his new Gotway 14" (one or two cells overheating in the pack). The Gotway does make warning beeps but shuts down nearly immediately, leaving him no time to react and badly bruised. Twice ! That's something that would not happen had this bloody cutoff not been implemented at the outset in the firmware (!).

If there were a comparison chart saying such wheel can shutdown (no matter with warning beeps or not) and such wheel does not, nobody in his right mind would buy the former.

 

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Apart from the requirement to keep plenty of power in reserve to implement pedal tilt back reliably even for the 120kg heaviest riders, which will of course have the effect of reducing the top speed, the fact remains it will still not make a euc "safe".

Even the eucs that are considered "safe" such as my IPS132's will fail quite easily and with so little warning that it can't be acted upon if put in a situation where they don't have the required power. On climbing long hills we've noticed that we need to accelerate very slowly and steadily for the motor not to be overtaxed and fail with at most a single beep as it's failing.

This situation has occurred several times and is easily repeatable.

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Bryan's quite right, most Wheels, even those like the IPS132/121 & the Solowheel have their intrinsic limits as well. On level ground with a 70kg rider (for example) is one thing; but with a 120kg rider, add a gradient, with even a slight acceleration & the power requirements shoot up exponentially. Throwing more power (such four parallel battery packs) at the problem can help a lot, but even then it's hardly infinite. eWheel owners should understand the capabilities of their Wheels & ride appropriately.

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Even the eucs that are considered "safe" such as my IPS132's will fail quite easily and with so little warning that it can't be acted upon if put in a situation where they don't have the required power. On climbing long hills we've noticed that we need to accelerate very slowly and steadily for the motor not to be overtaxed and fail with at most a single beep as it's failing.

It depends on what you mean by "fail".

  • If the motor "fails" because of lost steps by the motor controller, all you will feel is vibrations which will scare you to slow down. It's something easily manageable even with a stepper motor with no hall sensor, so a euc motor with 3 hall sensors feedback should cause no problem in case of lost step.
  • If the motor "fails" because the software shuts down power, sorry to insist, it's just dumb. There is NO reason to do that, even on an "overtaxed" motor.

The debate is obscured somewhat by imprecise terminology and by changing goalposts.

I am talking about the stupidity to purportedly shutting down power instead of keeping it within limits and let the user sort it out BY HIMSELF. And nothing else. I never deny the fact that an euc is not safe (a bicycle is not safe either, hey, it can fall by both sides, the only safe device must have at least 3 wheels).

But why on Earth making it even less safe by power shutdowns ??? It defies elementary logics. I still don't see any good reason to shutdown at low speed/high torque and even less at high speed !

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It depends on what you mean by "fail".

  • If the motor "fails" because of lost steps by the motor controller, all you will feel is vibrations which will scare you to slow down. It's something easily manageable even with a stepper motor with no hall sensor, so a euc motor with 3 hall sensors feedback should cause no problem in case of lost step.
  • If the motor "fails" because the software shuts down power, sorry to insist, it's just dumb. There is NO reason to do that, even on an "overtaxed" motor.

The debate is obscured somewhat by imprecise terminology and by changing goalposts.

...

I assume Gimlet did not really mean that the motor is failing. GoIng up a hill accelerating a bit too much with a heavy rider and mabee not full batteries can push the whole system past its limits - there is not enough power left to tilt the pedals, so the euc "leans" forward and has to try to accellerate even more but is not capable. So you "slowly" but for sure will fall off to the front.

unsafe eucs will/could shutdown in such situations, "safe" ones will try to give what they can and you fall off a little bit "slower" (or you can acrobaticly balance it out)

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Apart from the requirement to keep plenty of power in reserve to implement pedal tilt back reliably even for the 120kg heaviest riders, which will of course have the effect of reducing the top speed, the fact remains it will still not make a euc "safe".

Even the eucs that are considered "safe" such as my IPS132's will fail quite easily and with so little warning that it can't be acted upon if put in a situation where they don't have the required power. On climbing long hills we've noticed that we need to accelerate very slowly and steadily for the motor not to be overtaxed and fail with at most a single beep as it's failing.

This situation has occurred several times and is easily repeatable.

This sounds like the next firmware version is needed - the controller should(could) know that you are going uphill and that more power is needed - so he should start accordingly at lower speeds to tilt the pedals back to stop you.

could also be, that the system is overheating and by some kind of safety mechanism its just delivering less power, so it is suddenly beyond its "new" limits - which could (and should) be refined in software, too.

Only if there is a sudden change from flat to going uphill, the euc cannot know this upfront and comes to a situation thats powerwise not possible to handle for the euc. So there the rider has to think in advance and deccelerate accordingly before going uphill

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This sounds like the next firmware version is needed - the controller should(could) know that you are going uphill and that more power is needed - so he should start accordingly at lower speeds to tilt the pedals back to stop you.

Considering that the EUC only has a gyroscope (and maybe accelerometer?), I don't think it could "know" whether you're going uphill or not, or if the extra power is required simply because of heavier rider or more lean forwards... all it knows is whether the wheel is tilted or not. I'd claim it cannot distinguish any slope you're riding from any other situation where more power is needed.

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Considering that the EUC only has a gyroscope (and maybe accelerometer?), I don't think it could "know" whether you're going uphill or not, or if the extra power is required simply because of heavier rider or more lean forwards... all it knows is whether the wheel is tilted or not. I'd claim it cannot distinguish any slope you're riding from any other situation where more power is needed.

 

Could be.

So lets rephrase my above statement. The EUC should(could) be aware of the actual power consumption it needs to maintain the current velocity (no matter if it's going uphill, flat, downhill and regardless the drivers weight). In combination with the battery pack voltage (remaining charge - available power) the EUC should(could) choose an valid limit for tilting the pedals back before it is no longer possible.

Like in the example above from Gimlet - going uphill for longer time he can only accelerate very gently before failure - it seens like the EUC misses this point to tilt back/warn the driver, the available power is not sufficient for balancing and the EUC tilts forward and you fall off..

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Like in the example above from Gimlet - going uphill for longer time he can only accelerate very gently before failure - it seens like the EUC misses this point to tilt back/warn the driver, the available power is not sufficient for balancing and the EUC tilts forward and you fall off..

The problem is that at the instant where the EUC lacks the torque to go up a hill it also lacks the torque to tilt back. In fact, the wheel is trying to tilt back in order to keep the pedals level as you go up the hill! It's just that there's no torque left, so the pedals lean forward as you try to drive it up the hill.

By the time the wheel detects this situation it is too late. The only solution is a larger margin of safety that holds back more performance so that it can tilt back the pedals in this situation. To make this variable rather than a large wasteful static margin of safety, the wheel would need terrain mapping to detect that a steep hill is coming up in the next few meters and thus tilt back even though the situation at this instant is okay. Even then, we all know that it's possible to suddenly hit a bump and be knocked off balance, those can happen even when the terrain seems smooth and level. 

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