Alex_U

King Song 18a 1360wh top speed fall

145 posts in this topic

I would believe that setting the top speed at 40kph was where the mistake was, but I have no idea. So far my ks-18a 800w  that i constantly hit 30kph with has been rock solid.

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I noticed if I pick up my 18 with the wheel turned on, it will max out its Freewheel speed at 40kph. Ut probably thought it was freewheeling at that point

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normally the Ks18 1200 watt can handle 40 kmh...

but there are other questions? whats your weight...was it a msssive downhill? why the tiltback downt work or dif you just not recognize it?

i would have suggest a more safety till motor cut off...test it by pulling up the wheel at about 60percent batterie like in that case...

on your app you can than see the motor cut off max speed....

 

someting went wrong here....after the constantly beeping you SHOULD have slowed down...perhaps because of the downhill where the wheel is not horizontal in any way you do not recognize the tiltback....

do the max cut off test by lifting it up....i guess it will be higher than 45.... but then you weight and bumps also plays a roll...

fact is: wheel warned you by massive beeping that the limit is reached....

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Glad to hear you are healing quickly and did not sustain major injuries.

Having said that, I want to thank you for being "a bit stupid", and teach everyone reading this forum how to deal with those maximum speed specification. I want to add one important important remark to this discussion:

The KS18a 1200W will beep twice when you overcharge the batteries (no matter what speed you are going). If you are already driving with full beeps, the first overcharge warning beeps will go unnoticed. I admit that I have driven on full beeps too, but after my experience yesterday, i will always reduce speed when the double-beep speed alarm goes. 

My experience yesterday was driving my ks18 all the way (depleting the battery). I will make it a new topic later today.

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Swimming truncks at 45Kmh, really?!!! Man man man, you are one lucky bastard, it's a miracle you're still in one piece.

As Esay already said, any wheel will switch off or drop you at close to max speed. Standing still the motor has 100% torque and (obviously) no speed, at max speed you'll have no torque (to keep upright).

Personally I follow 3 rules: protective gear allways, no riding at max speed (or push it to the llimit) below 60V (80% batt capp.), and no riding below 58V (60% batt capp.) if I can help it. Which in your case with a 1360wh as you stated this leaves you with a effective 'safe' range of around 32Km. With my IPS T680+ I get exactly the same range at 25Kmh, and I'm 100Kg. You didn't state your weight, but even then, 32Km using 40% of your batt seems a lot. Or you are 100kg+ guy that rides continuously at 40kmh+ up and down slopes, or there might be something wrong with the battery.

Good luck healing man, may the Big Rider watch over you on your next runs.

 

 

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On 6/19/2016 at 11:02 AM, Alex_U said:

it will reach 45 km/h pretty quick, after what gyroscope will be switched off, wheel will stop turning,

We haven't received/sold any of the 40kph KS 18s but it sounds like this is something KS need address pretty soon for this variant.  

When visiting the factory, I was told by the Engineers that the 1200W motors had a 10kph safety reserve on them (motor capable of 50kph), but clearly the lift test demonstrates that the control-board limits to 45kph, which isn't a great deal of margin. IMO this Wheel either needs to be reduced to 35kph or the firmware updated to support 50kph in a no-load lift test. 

Edited by Jason McNeil
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2 hours ago, Jason McNeil said:

We haven't received/sold any of the 40kph KS 18s but it sounds like this is something KS need address pretty soon for this variant.  

When visiting the factory, I was told by the Engineers that the 1200W motors had a 10kph safety reserve on them (motor capable of 50kph), but clearly the lift test demonstrates that the control-board limits to 45kph, which isn't a great deal of margin. IMO this Wheel either needs to be reduced to 35kph or the firmware updated to support 50kph in a no-load lift test. 

interesting info. Do you believe a 10KmH difference between the speed limit and no-load lift test max speed is enough (margin of errors)?

My IPS T680+ is limited to 30Kmh, and the no-load lift test shows a (theoretical) max speed of almost 47Kmh.

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15 hours ago, HunkaHunkaBurningLove said:

If you need to go 50 kph buy a wheel that can go 55-60 kph and so on.

Are there any such wheels on sale?

14 hours ago, KingSong69 said:

 what's your weight...was it a massive downhill? why the tiltback did not work or did you just not recognize it?

do the max cut off test by lifting it up....i guess it will be higher than 45.... but then you weight and bumps also plays a roll...

My weight is 68 kg (150 lb). Downhill angle was less than 5 degrees. The tiltback did not work, I'm pretty sure - I would have definitely noticed if it had worked. I know how the tiltback feels at 20 km/h, at 40 - it should have been no difference.

Max cut off test by lifting up is exactly 45 km/h on my wheel.

Edited by Alex_U
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Interesting that the 1100W motor-version has the same lift-test cutoff speed as the 800W-motor version.

On my 16 I can easily push to 5 kph over the tiltback setting. I can see how you could, too. Specially downhill.

My recommendation: set the tiltback to 35kph, as you can then push on that to 40kph, leaving you an extra 5 kph safety margin (to avoid hitting the 45kph cutoff). Or alternatively set the beeps to 40kph, and always immediately slow down when you hear beeping.

Do note as well that the cutoff speed will be slightly lower during low voltage conditions. You can test this by doing a lift-test when battery is at 30% for example.

Edited by edwin_rm
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2 hours ago, Jurgen said:

Do you believe a 10KmH difference between the speed limit and no-load lift test max speed is enough (margin of errors)?

It's just a theory, but it's awfully suspicious that both KS & GW have a cut-off speed of 45kph in a 'no-load' lift test, maybe the PWM IC can only switch up to a maximum rate? @esaj & @lizardmech, along with some of the other resident experts, might be in a better position than I am to indicate whether this is true or not.

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3 minutes ago, Jason McNeil said:

It's just a theory, but it's awfully suspicious that both KS & GW have a cut-off speed of 45kph in a 'no-load' lift test, maybe the PWM IC can only switch up to a maximum rate? @esaj & @lizardmech, along with some of the other resident experts, might be in a better position than I am to indicate whether this is true or not.

Not that familiar with the capabilities of the driver ICs, as I've only built the drivers from discrete components, but I doubt it's an issue. Based on what I know, usually in motor-drives the PWM-frequency doesn't change, only the duty cycle.

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14 hours ago, Mistagear said:

Despite wearing considerably more safety gear, it's been about 6 weeks recovering (and not back to riding yet) so Alex, you are one, VERY LUCKY rider

Probably I am, but I had not recognized it until I read your posts, lads. My injuries are on the pictures (3 days after fall). Now I understand, I was very lucky on that day. Right after falling I checked my condition - there was no bleeding. Those were excellent news, because there was 7 km to my home to roll. After I checked my wheel: switched it off and on, re-established gyroscope, everything seemed OK.

I don't remember any strong pain at that moment, just was a bit disappointed that people in passing cars saw me falling (it happened on a highway). A man on a rolling wheel is rare in our region, it's a kinda like a legend, like a unicorn - everyone talks about it, but few have really seen it. A man rolling at 40 km/h is even more unique - you start realizing that cars, overtaking you, are not that fast any more. A man falling at 45 km/h on tarmac is just a show and you feel yourself a central clown - not a good feeling, I might add.

Anyway, I stepped on pedals and started rolling in 2 minutes after fall. In a few seconds of vertical position I felt there was something wrong with my eyes - black cloud started growing right from the centre to periphery. It was an absolutely shiny day, no clouds in the sky, almost midday and I could not see anything in front of me. I understood that if I had continued then I would have lost my conscience. I stopped, bent myself forward and started intensively breathing. In bent position it really felt better, vision recovered. I rolled again, but in a few seconds of vertical position there was the same effect. As I understand now, my brain had not finished by that time analysing how damaged my body was in and outside, in other words it was the total integrity check of all my organs. And until it's done, the brain really wanted to stop me and the only way to do that was to power off my conscience. I resisted. For the third time I stepped on pedals. It's really strange, I absolutely controlled my balance, but could not control my vision - black growing stain right in the middle again. And when stopped and bent again, I felt something different in my head - that was a feeling of light cold. I understood, my brain had finished its analysis and would not have tried to stop me any more. After that I rolled home without stops. I have to say I did not hit my head and had no headache neither then, nor now.

20160620_200312_resize.jpg

20160620_200519_resize.jpg

20160620_200616_resize.jpg

20160620_200851_resize.jpg

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5 hours ago, Jason McNeil said:

When visiting the factory, I was told by the Engineers that the 1200W motors had a 10kph safety reserve on them (motor capable of 50kph), but clearly the lift test demonstrates that the control-board limits to 45kph, which isn't a great deal of margin. IMO this Wheel either needs to be reduced to 35kph or the firmware updated to support 50kph in a no-load lift test. 

Absolutely right. There should be a fool-proof. I was absolutely sure, that first of all the wheel would have tilted back at 40 km/h as it did at 20. But secondly I could not have expected that it would have cut itself off at 45 (I did a lift test on the second day after fall only and had not known that before). And the problem is not related to insufficient power, it's a program bug - too low margin. I'm pretty sure there was more than enough power in my wheel to let me roll and roll, but reaching that speed limit of 45 and programmed power cut off was a back stab, I could not have imagined. Now I know the root cause.

Who should I ask to improve firmware to do it one way (reduction to 35) or the other (power cut off speed limit increase to 50 kph)?

Edited by Alex_U
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38 minutes ago, edwin_rm said:

My recommendation: set the tiltback to 35kph,

I will definitely follow these recommendation, because they are all logical. But what Alarm trigger in App Menu can do that: 1, 2, 3 or Ollie? I tried to figure it out on the second day, but did not complete my trials due to lack of time.

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20 hours ago, esaj said:

45km/h crash with no protective gear? :o  Pretty much all the wheels will power off after reaching max speed, but even if they didn't. the motor wouldn't have enough torque left to keep you balanced (the pedals would still just "fall" forward). AFAIK, you cannot stop the wheel from powering off, just don't ride that fast.

As for the tilt-back not reacting, setting it that high might mean that the motor no longer has enough torque to lift them at that speed. Set it lower.

Good emoji, that is extremely fast to fall from.

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2 hours ago, Alex_U said:

Probably I am, but I had not recognized it until I read your posts, lads. My injuries are on the pictures (3 days after fall). Now I understand, I was very lucky on that day. Right after falling I checked my condition - there was no bleeding. Those were excellent news, because there was 7 km to my home to roll. After I checked my wheel: switched it off and on, re-established gyroscope, everything seemed OK.

I don't remember any strong pain at that moment, just was a bit disappointed that people in passing cars saw me falling (it happened on a highway). A man on a rolling wheel is rare in our region, it's a kinda like a legend, like a unicorn - everyone talks about it, but few have really seen it. A man rolling at 40 km/h is even more unique - you start realizing that cars, overtaking you, are not that fast any more. A man falling at 45 km/h on tarmac is just a show and you feel yourself a central clown - not a good feeling, I might add.

Anyway, I stepped on pedals and started rolling in 2 minutes after fall. In a few seconds of vertical position I felt there was something wrong with my eyes - black cloud started growing right from the centre to periphery. It was an absolutely shiny day, no clouds in the sky, almost midday and I could not see anything in front of me. I understood that if I had continued then I would have lost my conscience. I stopped, bent myself forward and started intensively breathing. In bent position it really felt better, vision recovered. I rolled again, but in a few seconds of vertical position there was the same effect. As I understand now, my brain had not finished by that time analysing how damaged my body was in and outside, in other words it was the total integrity check of all my organs. And until it's done, the brain really wanted to stop me and the only way to do that was to power off my conscience. I resisted. For the third time I stepped on pedals. It's really strange, I absolutely controlled my balance, but could not control my vision - black growing stain right in the middle again. And when stopped and bent again, I felt something different in my head - that was a feeling of light cold. I understood, my brain had finished its analysis and would not have tried to stop me any more. After that I rolled home without stops. I have to say I did not hit my head and had no headache neither then, nor now.

20160620_200312_resize.jpg

20160620_200519_resize.jpg

20160620_200616_resize.jpg

20160620_200851_resize.jpg

@Alex_U that is a very good description of your brain stopping you from doing more damage to your body.  It takes a little time for the brain to realize what just happened.  And it prevents more damage if you listen,  but after awhile it's like riding through tiltback and your brain gets used to it and then what?  Super Ow ow ow.

Edited by steve454
You did hit your head, you have a concussion.
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@Alex_U Ollie = Tiltback. Also, I have experience the "blackout" after a wipeout that you described as well. One time I wrecked and then got back on my unicycle immediately, to save face, as I was embarrassed about falling in public. Because I didn't give my body time to recover, I lost consciousness momentarily and wiped out again! Double the embarrassment! Lesson Learned: always take a few minutes break from riding after a crash, so as to allow the body to process what happened and recover.

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