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Nils

KS16B cut off

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Hi all,

so I had my first crash today. I bought my KS16B last year (second hand), but it's only this year that I've started to put it to some serious use. It's been working pretty well for me up until today. I've put the third warning and the tilt back at the maximum, 30kmh (~18mph) and have disabled the first two warnings. I typically drive right below the maximum speed whenever the situation allows, but I respect the beep and throttle down when I hear it. This has worked out well for some time, but today it didn't. I had been out driving for approximately 30 minutes or so in the nice weather (25C/77F) when I drove down a (fortunately empty) bicycle lane; a slight decline followed by a slight climb. Somewhere in the middle of this, cruising along at approximately the top speed, I suddenly feel a complete loss of stabilization underneath me, like the wheel just shut off. A few wobbly meters later, trying unsuccessfully to keep my balance without any help, it was time to eat the  asphalt. Fortunately I managed a pretty controlled fall (which I tentatively attribute to martial arts training in my earlier years), and managed to land on my right side and roll with it. All in all I scraped and bruised the right side of the body: lower leg, knee and buttock and I'm out of pair of shorts, but I escaped unscathed otherwise.

I'll feel it for some time, but things could definitely have been a lot worse - I'm in particular not fond of the idea of this happening in the middle of traffic. I'm also a little bit surprised since my perception of Kingsong was that they played it relatively safe with the tilt back and max limit (compared to GW for instance). I'm of pretty normal/large  northern size, which means a load of slightly below 90 kg (198 pounds) with gear and backpack on, but I guess that's the at the top end of the weight range being tested for (though the official max load is at 120kg unless I'm mistaken). Also, I had been riding a bit before this today, so the battery was at around 50% or so when this happened. I'm guessing that the decline followed by the climb, with me leaning into it somewhat pushed the wheel over the capacity before the warning/tilt back could kick in.  Still, it would be interesting to hear if anyone else has had similar experiences with this wheel or have some other interesting reflections? Also, this has understandably sullied my view on Kingsong when it comes to safety margins. Considering that they're kind of known for playing it safe (again, compared to GW), I'm wondering if anyone has any insight in the development of their current wheels compared to the KS16 in this regard? They're all more powerful, which helps of course, so perhaps that alone makes this less of an issue.

Meanwhile, I guess I'll lower the third warning for now and start thinking more actively on getting a more powerful wheel. I had been planning on doing that first next year, but..

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Posted (edited)

@Nils maybe you want to take a look at 

 

Its not only the speed, but a combination of speed, acceleration(incline) and battery charge...

Edited by Chriull

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Posted (edited)

Sorry to hear about your fall.  I'm 100kg and a couple times I have felt the pedals dip when I've asked too much of the wheel, but I've never had it cut out on me.  It's part of the reason why I like to ride in 'player' mode, because if the pedals become soft you notice it right away.  I've always had the speed set to 30km/h and rode that wheel for about 4000km.  Is your wheel still functioning after the fall?

 

Edited by Xoltri

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Doesn't sound like a cut of since you were able to stay upright for a few meters.  That says it was still working vs a cut off is just you slamming into the asphalt.  You wouldn't be able to react in that instance.  Not sure what happen here.

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5 hours ago, Chriull said:

@Nils maybe you want to take a look at [..]

Its not only the speed, but a combination of speed, acceleration(incline) and battery charge...

Thanks @Chriull, that seems to be exactly what happened to me. Like you say, it seems to be a combination of factors such as speed, acceleration and battery charge. As for me I typically ride with more charge in the wheel as my typical rides (commuting) are shorter and I top it up regularly. It didn't seem that much of a climb to me, but if one is already pushing it and the battery charge is lower than what is typically the case  the margins would be smaller.

 

2 hours ago, Xoltri said:

Sorry to hear about your fall.  I'm 100kg and a couple times I have felt the pedals dip when I've asked too much of the wheel, but I've never had it cut out on me.  It's part of the reason why I like to ride in 'player' mode, because if the pedals become soft you notice it right away.  I've always had the speed set to 30km/h and rode that wheel for about 4000km.  Is your wheel still functioning after the fall?

Thanks! The wheel is fine, except some missing side padding. I got on it afterwards and rode home without any issue. Do you also have the KS16 then? At what speed do you typically ride it?

 

1 hour ago, eddiemoy said:

Doesn't sound like a cut of since you were able to stay upright for a few meters.  That says it was still working vs a cut off is just you slamming into the asphalt.  You wouldn't be able to react in that instance.  Not sure what happen here.

Yes, after posting I read some other post addressing the differences between cut off and over lean and you're right, it was not a cut off in the sense I understood it from that other post.

My takeaway so far is that when riding a wheel (or this wheel at least) close to its capacity you have to be very careful regarding incline and lean, with the the battery charge also being an influencing factor, lest you push the wheel beyond its capabilities. This based on the data from @Chriull collected from another unfortunate co-wheeler suffering the same fate. A speed limit warning won't help here obviously as it's the effect and not speed that is the issue. I'm guessing newer wheels have improved in this regard compared to the KS16 as well though? From what I understand the V10F for instance continually lowers the max speed limit depending on charge (it being one factor at least). Now, The V10F seems to have its own issues at the moment with firmware and perhaps being to aggressive in lowering the max limits, but the reasoning seems sound.

I've read some other post talking about experienced riders developing a feel for how much their wheels can take before giving out, but that does not really sound like a working answer considering the possible consequences of an error in judgement. If it's not possible to make a satisfactory system for warnings/degradation (and it doesn't seem easy),  then the safest thing seems like getting a wheel powerful enough that it has ample over-capacity at the speeds/situations you want to ride it in.

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Yeah, I have the KS16B but I bought an MSuperX so I'm riding that now.  I did ride it at 30km/h, mostly between 80% and 40% battery (only charging to 80% is much better for the packs, as long as you occasionally charge to 100% so they can properly balance the cells).

Basically, in my opinion the only real safety system for EUC's at this point is to buy one with way more than enough power and ride it well below the limit.  That was one of my reasons for buying the MSuperX, it has a top speed of 55km/h but I have the tiltback set to 36km/h.  Well that, and the big cushy tire, which is glorious on imperfect pavement.

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57 minutes ago, Nils said:

Thanks @Chriull, that seems to be exactly what happened to me. Like you say, it seems to be a combination of factors such as speed, acceleration and battery charge. As for me I typically ride with more charge in the wheel as my typical rides (commuting) are shorter and I top it up regularly. It didn't seem that much of a climb to me, but if one is already pushing it and the battery charge is lower than what is typically the case  the margins would be smaller.

 

Thanks! The wheel is fine, except some missing side padding. I got on it afterwards and rode home without any issue. Do you also have the KS16 then? At what speed do you typically ride it?

 

Yes, after posting I read some other post addressing the differences between cut off and over lean and you're right, it was not a cut off in the sense I understood it from that other post.

My takeaway so far is that when riding a wheel (or this wheel at least) close to its capacity you have to be very careful regarding incline and lean, with the the battery charge also being an influencing factor, lest you push the wheel beyond its capabilities. This based on the data from @Chriull collected from another unfortunate co-wheeler suffering the same fate. A speed limit warning won't help here obviously as it's the effect and not speed that is the issue. I'm guessing newer wheels have improved in this regard compared to the KS16 as well though? From what I understand the V10F for instance continually lowers the max speed limit depending on charge (it being one factor at least). Now, The V10F seems to have its own issues at the moment with firmware and perhaps being to aggressive in lowering the max limits, but the reasoning seems sound.

I've read some other post talking about experienced riders developing a feel for how much their wheels can take before giving out, but that does not really sound like a working answer considering the possible consequences of an error in judgement. If it's not possible to make a satisfactory system for warnings/degradation (and it doesn't seem easy),  then the safest thing seems like getting a wheel powerful enough that it has ample over-capacity at the speeds/situations you want to ride it in.

I have the ks16 and ride the limit so it is beeping the whole time.  I guess if you are talking about overlean, when you hit the max, 30km/h, the wheel can’t go any faster, so if you lean more expecting the wheel to catch up with you then you will fall.  I’ve had a couple of near misses with ovetlean. But it is always when I was accelerating from low speeds, but managed to catch myself.   It does take more riding to feel.  But it is really scary when it happens.  When I’m riding 30km/h, I get a genial tiltback to prevent overlean, but with effort, you can over come it at your own detriment.  

‘Don’t let this incident deter you from enjoying your wheel.  With experience you will learn the limits and be able to stay with in them for a safe and happy ride.  Good luck!

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18 hours ago, Xoltri said:

Basically, in my opinion the only real safety system for EUC's at this point is to buy one with way more than enough power and ride it well below the limit.  That was one of my reasons for buying the MSuperX, it has a top speed of 55km/h but I have the tiltback set to 36km/h.  Well that, and the big cushy tire, which is glorious on imperfect pavement.

Yes, that matches my own thinking (and also my preferences speed wise). I believe I'll follow in your footsteps I buy a more powerful wheel once I've decided on what exactly the next wheel will be.

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17 hours ago, eddiemoy said:

I have the ks16 and ride the limit so it is beeping the whole time.  I guess if you are talking about overlean, when you hit the max, 30km/h, the wheel can’t go any faster, so if you lean more expecting the wheel to catch up with you then you will fall.  I’ve had a couple of near misses with ovetlean. But it is always when I was accelerating from low speeds, but managed to catch myself.   It does take more riding to feel.  But it is really scary when it happens.  When I’m riding 30km/h, I get a genial tiltback to prevent overlean, but with effort, you can over come it at your own detriment.  

‘Don’t let this incident deter you from enjoying your wheel.  With experience you will learn the limits and be able to stay with in them for a safe and happy ride.  Good luck!

Well the problem wasn't that I leaned to much forward at top sped and fell off - I was properly balanced and approximately centered on top of the wheel and it just stopped supporting me. I believe so far that several factors just conspired to push the wheel beyond it's capacity fast enough that it didn't have time/power to engage the kickback/warning. More specifically I'll be cautious when switching from a decline to an incline around max speed, while considering a more powerful wheel for the future. And thanks for your well wishes, I'm already bitten so this won't deter me :)

 

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Nils, it seems we are riding quite similarly in many respects. I'm at your weight plus a few, riding the same kind of wheel at the same settings, and for the record in quite the same location. The difference is my wheel has never failed on me. I bought mine new three years ago and have been riding 1000 km by now. Your story is pretty frightening! I think I practice my wheel just like you describe. Always retreating a bit on the first beep but otherwise keeping the speed up.

What I have noticed lately is that the wheel seems to start beeping at less than 30 km/h if the battery is below like 50%. That hasn't happened before as far I have noticed. I don't know if it might be a sign of an aged battery pack or if there is a recent change in the firmware. I did update the firmware a few weeks ago, and this has probably started happening after that. If so, perhaps the firmware is adopted to handle the wheel more safely on a not fully charged battery? What version are you on?

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12 hours ago, Johey said:

Nils, it seems we are riding quite similarly in many respects. I'm at your weight plus a few, riding the same kind of wheel at the same settings, and for the record in quite the same location. The difference is my wheel has never failed on me. I bought mine new three years ago and have been riding 1000 km by now. Your story is pretty frightening! I think I practice my wheel just like you describe. Always retreating a bit on the first beep but otherwise keeping the speed up.

What I have noticed lately is that the wheel seems to start beeping at less than 30 km/h if the battery is below like 50%. That hasn't happened before as far I have noticed. I don't know if it might be a sign of an aged battery pack or if there is a recent change in the firmware. I did update the firmware a few weeks ago, and this has probably started happening after that. If so, perhaps the firmware is adopted to handle the wheel more safely on a not fully charged battery? What version are you on?

I'm on 1.25, which the app claims is the latest firmware. I did have a look around when this happened just to check on the firmware status and then found this:

https://eunicycles.eu/en/news/aktualne-wersje-firmware

That page claims the latest version would be 1.27, but as I said the app (the new one) says otherwise. What version are you on? I have the 680 Wh battery for what it's worth, so that would be one difference compared to your wheel. I've since ridden the wheel daily without any issues for what it's worth, but I do ride a little bit more cautiously now, in particular I throttle down a little when climbing.

You're in my area then by the way? I'm thinking that come autumn I'll see whether there's any interest for a group ride :)

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I'll check the firmware version tomorrow. I have a very old app I don't even remember if I installed from Playstore or manual apk.

I'm usually riding in Södertälje, although today I had a nice tour in Stockholm. I'm all in for a group ride! :)

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