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Sudden KS16 cutout ???


HermanTheGerman

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@Diana@szkingsong.com he seems to accelerate slowly and not rigth after the start :
" I was riding at low speed talking to a Cyclist "

Never had this issue with KS16S but i never truly feel safe cause alarm aren't link with engine couple. That's something who may lead me to buy an gotway. But wait and see, firmware evolve with time :)

Edited by Fitz0uille
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14 hours ago, Diana@szkingsong.com said:

I am Diana from King Song. I have talked with our research engineer about it. He thinks you may accelerated too much at the beginning. You'd better accelerate after you ride 2m.

No, if you read my 1st and the following posts, I explain that it only happens under very special circumstances, at very slight accelerations, just at the start. I never had a problem until now when accelerating fast.

But because the problem only happens very rarely I think it will be difficult to find.

Besides the mentioned rare events the KS16B is until now a very reliable wheel (more than 2300 km on it).

6 hours ago, cm16600 said:

@Diana@szkingsong.com thank you for the support but i was actually riding the Euc  so maybe it  was 15 kph and then accelerate up to 25 until the wheel cut off.


This must be a different problem, because until now I never had a cutoff while riding, and I use the wheel heavily (e.g. with FW 1.23 I once had a short acceleration up to 39 km/h, and there was no problem, the wheel handled it fine).

Edited by HermanTheGerman
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9 hours ago, cm16600 said:

@Diana@szkingsong.com thank you for the support but i was actually riding the Euc  so maybe it  was 15 kph and then accelerate up to 25 until the wheel cut off.

3 hours ago, HermanTheGerman said:

No, if you read my 1st and the following posts, I explain that it only happens under very special circumstances, at very slight accelerations, just at the start. I never had a problem until now when accelerating fast.

But because the problem only happens very rarely I think it will be difficult to find.

Besides the mentioned rare events the KS16B is until now a very reliable wheel (more than 2300 km on it).


This must be a different problem, because until now I never had a cutoff while riding, and I use the wheel heavily (e.g. with FW 1.23 I once had a short acceleration up to 39 km/h, and there was no problem, the wheel handled it fine).

 

I am very pleased to discuss some problems with all of you.I never had a cut off while riding.King Song is a very reliable electric unicycle brand, which has great reviews all over the world.

 

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  • 2 years later...

I actually had an engine cut out with my KS16S a couple days ago. I took a look at the logs and it looks like a power failure. I managed to identify the cutout at 15:46:55, when speed went from 25.99 to 15.4 and then zero one second later. Engine output went from 636 to 73 then 14, which I figure is when I hit the ground. 

The logs show that I was riding close to the limit of 35km/h on a flat surface for a few seconds. I then stopped and took a sharp left slowly. I started going uphill, but the inclination was really mild. Still according to the logs, I was riding at 25km/h for a few seconds when I felt that the gyroscope force was no longer there. I got a crazy pedal dip and then managed to take a few steps before hitting the ground. 

I talked to KingSong reps and they seem to think it's a faulty mainboard. I was expecting to be a problem with the battery (some dead cell perhaps) or perhaps some fuse. I actualy have no idea what caused that, but it sure surprised me as I was under the impression engine cutouts wouldn't happen with the KS16S.

But it certainly does. Keep that in mind.
 

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1 hour ago, Marco T Bastos said:

.... I was under the impression engine cutouts wouldn't happen with the KS16S. ....
 

No one should have this mistaken impression about any wheel.  They will fail and they do fail, and that is all wheels.  Keep your safety gear on.  

 

I hope you were not injured too bad.

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3 hours ago, DannyK said:

That scares me man:unsure: 

("Healthy") fear is what keeps us alive😎

3 hours ago, DannyK said:

Though Im riding 16x, idea of some error like that could kick in and cut me off from the wheel at speed above 45kph is terrifying.. I hope the gods that doesnt happen to my wheel

As the EUCs just have one wheel any (serious) fault will sent one flying! Be it bad/loose connectors, wiring, hall sensors, motherboard ....

No matter which brand or modell. (Although some have a bit better records than others...)

Fortionately such QA issues show up rather quickly and after "testing" ones new wheel for some time, one should be quite "secure"...

But it can happen everytime, although for gods sake very seldomly, that some wire desolders, a mosfet fries, something breaks once one had some unusal burdens or just by bad luck... :(

At speeds like your mentioned 45 kph some safety gear as "back up/insurance" is highly recommended!

10 hours ago, Marco T Bastos said:

I talked to KingSong reps and they seem to think it's a faulty mainboard. I was expecting to be a problem with the battery (some dead cell perhaps) or perhaps some fuse. I actualy have no idea what caused that, but it sure surprised me as I was under the impression engine cutouts wouldn't happen with the KS16S.

KS16S has very good records. 

But quirks happen, qa is not (near to) perfect...

10 hours ago, Marco T Bastos said:

But it certainly does. Keep that in mind.

+1!

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  • 1 month later...
On 4/29/2020 at 9:48 AM, Chriull said:

Btw - you mind to share the logs?

Sorry for the very late reply. I wasn't getting the notifications. Here are the logs:

https://www.dropbox.com/s/sakk9d2z1xcf5yn/KS16S Engine Cutout.xlsx?dl=0

I went on a long ride that day, but battery was still over 71% when engine cut off.  

The rows you want to look at are 7135 to 7151. IIRC the cutout was at 15:46:55.

 

 

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On 4/28/2020 at 11:09 PM, FreeRide said:

No one should have this mistaken impression about any wheel.  They will fail and they do fail, and that is all wheels.  Keep your safety gear on.  

 

I hope you were not injured too bad.

I just got a really small scratch on my left arm. I got lucky because I didn't have much (any?) protective gear that day. The jacket surely helped, but what prolly made the difference was knowing how to fall. All those years of judo finally paid off. 

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On 4/29/2020 at 8:25 AM, Chriull said:

No matter which brand or modell. (Although some have a bit better records than others...)

Fortionately such QA issues show up rather quickly and after "testing" ones new wheel for some time, one should be quite "secure"...

KingSong has a pretty good record and my 16S had nearly 6K kilometres when I got the engine cut off. So go figure what causes these things. I'll get the wheel checked once the lockdown is lifted. Not sure I mentioned, but KingSong rep thinks the problem is the motherboard (old model vs. new model). Other folks think my riding style is too aggressive. Either way, I managed to put the wheel back together--the crash was pretty bad with several parts falling off (front light, front cover, side pads, etc.). Until it's properly diagnosed I won't be riding it over 30km/h. At 25km/h I think I can walk (run?) out of the crash if it happens again. The really terrifying scenario is an engine cut off above 40km/h. That's in the territory of 100m world record and you just can't step out of the wheel at this speed. Falling and rolling successfully at this speed should be pretty hard too. 

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10 hours ago, Marco T Bastos said:

Sorry for the very late reply. I wasn't getting the notifications. Here are the logs:

https://www.dropbox.com/s/sakk9d2z1xcf5yn/KS16S Engine Cutout.xlsx?dl=0

I went on a long ride that day, but battery was still over 71% when engine cut off.  

The rows you want to look at are 7135 to 7151. IIRC the cutout was at 15:46:55.

Your whole ride as current over speed diagram: (1)

total.png

One already sees the points on the topmost right side (at about 35 km/h and 35A) were you hit the systems limit and overleaned ;(

Just lines 7125 to 7151:

overlean.png

The "swarm of points" at about 34 km/h and 10+A was just before your overlean, then you accelerated (burdened) your wheel in "one instant" from 32 km/h & 5A up to 33 km/h & 35A.

This acceleration made you hitting with the next point of the log (~35 km/h & 37A) the torque limit of the wheel. This seems to be quite exactly the point of the torque over speed limit line, were the 35 km/h speed limit tiltback shortly still had a chance to kick in...

So I'd say your motherboard is still in a perfect shape, it seems

10 hours ago, Marco T Bastos said:

Other folks think my riding style is too aggressive.

+1 :ph34r:

Time to get a stronger wheel or ride more relaxed with this one. Especially important - no high accelerations at high(er) speeds!

BTW.: KS wheels report now (since FW ~1.07) a value called inverter load. EUC World logs this values in the log file. This value seems to be expressing how much percent of this limit one reached. Imho this also triggers the "88% alarm", if you have some recent firmware. Did you notice such an alarm? Imho 4 (?or more?) beeps from the buzzer in fast succession.

But you managed the overlean limit from line 7136 (31,5km/h&4,52A)  to 7138 (34,73km/h&36,6A) within ~0.8 seconds - so not much time to react on any alarm within this timespan...

(1) KS wheels report battery current - for this diagram (torque over speed) one would need the motor current. But we are interested in only the range near the max torque (== motor current) over speed limit - and at this limit battery current is (sufficient) equal to the motor current.

Edit: PS: for more details on overlean/max torque over speed limit you can take a look at 

This started out with a log from an overlean with an KS16C, later posts are in regard to the Ks16S, too and the KS18XL. And some observations in regard to the "inverter load" value.

Edited by Chriull
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Yeah, the wheel has been working alright after the cutout and crash, so I’m not sure why there would be a problem with the MoBo. Except perhaps for the overvoltage warning I got once or twice since. I was riding at 20-25 km/h, prolly even slower than that, when the wheel yelled “Be careful, overvoltage” (I find this warning scarier than the “please deaccelerate” because I’m not sure what the problem is). 

As for the cutout per se, your reading makes perfect sense. What did you plot that with by the way? If it’s Excel I must say it got a not better since I last used it. The only bit that doesn’t add up is that I reached 35 km/h a few good seconds before the cutout. IIRC I slowed down to make a sharp turn to the left and started going uphill (very mild inclination). By then I was cruising at no more than 25 km/h. That’s when it cutout. At 25 km/h instead of 35. No tilt back, not warnings, but what I can only describe as a power cut because the gyroscope force suddenly wasn’t there (it’s a lot harder to ride these things without the gyroscope force, that much I can tell you).

But yeah, chances are I need a more powerful wheel. I tried to explain to folks that I need a faster wheel to ride safely but they think I’m joking. I’m keeping an eye on this Veteran Sherman beast that’s coming out. If that thing suffers from cutouts too then we’ll need a whole new engineering approach to this. 

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I f i,m reading correctly, the fall was not from any problem with the wheel and there was no cutout but the fault is from the operator who overleaned ?

Please correct me if i,m wrong!

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6 hours ago, Daley1 said:

I f i,m reading correctly, the fall was not from any problem with the wheel and there was no cutout but the fault is from the operator who overleaned ?

Please correct me if i,m wrong!

Nope. There was a cutout for sure. Whether it’s caused by overleaning alone is what we’ve been talking. 

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Just now, Marco T Bastos said:

Nope. There was a cutout for sure. Whether it’s caused by overleaning alone is what we’ve been talking. 

It feels like a cut out, but was just caused by hitting the torque over speed limit == overlean.

6 hours ago, Marco T Bastos said:

Yeah, the wheel has been working alright after the cutout and crash, so I’m not sure why there would be a problem with the MoBo. Except perhaps for the overvoltage warning I got once or twice since. I was riding at 20-25 km/h, prolly even slower than that, when the wheel yelled “Be careful, overvoltage” (I find this warning scarier than the “please deaccelerate” because I’m not sure what the problem is). 

The overvoltage comes while braking going downhill? After fully charged the wheel or after longer downhill parts?

... then it's "normal" behaviour"...

6 hours ago, Marco T Bastos said:

As for the cutout per se, your reading makes perfect sense. What did you plot that with by the way? If it’s Excel

Yes - libre office, but the same can be done with excel.

6 hours ago, Marco T Bastos said:

The only bit that doesn’t add up is that I reached 35 km/h a few good seconds before the cutout. IIRC I slowed down to make a sharp turn to the left and started going uphill (very mild inclination). By then I was cruising at no more than 25 km/h. That’s when it cutout.

The part of your log above was well about 30 km/h the while time befor the overlean. Overlean happened at about 35 km/h.

Or do you have the ~25km/h numbers from some gps recording/gps tracker?

6 hours ago, Marco T Bastos said:

At 25 km/h instead of 35. No tilt back, not warnings, but what I can only describe as a power cut because the gyroscope force suddenly wasn’t there (it’s a lot harder to ride these things without the gyroscope force, that much I can tell you).

Once one hit this max torque (~current) over speed limit line the torque the wheel can provide the rider gets less with increasing speed. But by the rider leaning forward he would need constant (or maybe even increasing torque) to keep him upright. So since supporting torque decreases one falls forward == overlean. As this happens within fractions of a second it feels like a cutout, but it is not..

6 hours ago, Marco T Bastos said:

But yeah, chances are I need a more powerful wheel. I tried to explain to folks that I need a faster wheel to ride safely but they think I’m joking. I’m keeping an eye on this Veteran Sherman beast that’s coming out. If that thing suffers from cutouts too then we’ll need a whole new engineering approach to this. 

One can overlean every wheel! The limit is just at higher speeds and/or burdens!

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9 hours ago, Chriull said:

The overvoltage comes while braking going downhill? After fully charged the wheel or after longer downhill parts?

... then it's "normal" behaviour"...

 

More likely I was riding on flat surface, but battery was fully charged. There’s a good chance I was leaving backwards though, so chances are you’re spot on. 

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9 hours ago, Chriull said:

The part of your log above was well about 30 km/h the while time befor the overlean. Overlean happened at about 35 km/h.

Or do you have the ~25km/h numbers from some gps recording/gps tracker?

I have the ride on MapMyRide, which of course relies on GPS, but I’m not sure which odometer is worse. The differences can be substantial at times. 

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9 hours ago, Chriull said:

Once one hit this max torque (~current) over speed limit line the torque the wheel can provide the rider gets less with increasing speed. But by the rider leaning forward he would need constant (or maybe even increasing torque) to keep him upright. So since supporting torque decreases one falls forward == overlean. As this happens within fractions of a second it feels like a cutout, but it is not..

I actually fell backwards. I felt a crazy pedal dip and instinctively leaned back, only to realize there was no resistance from the wheel (that’s what I mean by saying the gyroscope was gone). I managed to pull back my center of gravity a little bit, but at this point the wheel was really “free wheeling” and I lost control. To be exact, I stepped back and out of the wheel, tried to keep the pace to the traveling speed, figured I wouldn’t make it, and rolled sideways. The wheel rolled over several times (quite the cinematic crash). Of course it all happens very fast, but the realization that you have no gyroscope grip (forwards or backwards) is pretty scary. 

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16 hours ago, Marco T Bastos said:

There‘s something about that scatterplot that couldn’t be Excel. 

It looks a bit different in libre office but similar scatter plots can be made with excel.

16 hours ago, Marco T Bastos said:

I actually fell backwards. I felt a crazy pedal dip and instinctively leaned back, only to realize there was no resistance from the wheel (that’s what I mean by saying the gyroscope was gone). I managed to pull back my center of gravity a little bit, but at this point the wheel was really “free wheeling” and I lost control. To be exact, I stepped back and out of the wheel, tried to keep the pace to the traveling speed, figured I wouldn’t make it, and rolled sideways. The wheel rolled over several times (quite the cinematic crash). Of course it all happens very fast, but the realization that you have no gyroscope grip (forwards or backwards) is pretty scary. 

Interesting description of the incident!

I looked again at the scatterplot - directly after the tiltback and overlean happening is one braking event. At ~38 km/h and ~-10A Then one 10A burden at ~30km/h. Maybe the point you unmounted?

After that just nothing - speed gets lower and no current.

Timely resolution is unfortionately very low from the logs - so no real details to be seen.

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I'm going to jump in and say the same thing happened to me ayear ago on my KS 16C. Basically what happened i was testing the tilt back going at max speed just to test it out and it worked, so i did it again near max speed but this time i done it more aggresively. Then it cuts out and breaks my colar bone (had no idea it was broken untill 6 days later) lol but heres the odd thing.... where i fell was also a deep pot hole. and as it was at night i cant be to sure if the pot hole took me outr or fast aggresive accleration near top speed to test tilt back. Took me a good year to fully relax and ride as normal. Got the 18xl now tho and am quite happy with that.

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2 hours ago, Neon EUC said:

I'm going to jump in and say the same thing happened to me ayear ago on my KS 16C. Basically what happened i was testing the tilt back going at max speed just to test it out and it worked, so i did it again near max speed but this time i done it more aggresively. Then it cuts out and breaks my colar bone (had no idea it was broken untill 6 days later) lol but heres the odd thing.... where i fell was also a deep pot hole. and as it was at night i cant be to sure if the pot hole took me outr or fast aggresive accleration near top speed to test tilt back. Took me a good year to fully relax and ride as normal. Got the 18xl now tho and am quite happy with that.

Yup. I got exceedingly lucky with my cutout crash. I was riding on a main road and things could’ve gone really bad. I’ve been thru some motorcycle crashes that similarly I couldn’t believe my luck. But you can’t count on luck. I better get a more powerful wheel before I run out of it.  

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