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Ks16s: how to get the best out of the 1200W motor?


Truong Do

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I have been with the wheel for a few days and very happy with it. Everyone in our group has found it stable and reliable. 

Today I took the wheel to a steep, short hill for a test. I shifted my feed to the front of the pedals as far as I could so I could lean on it aggressively. But I could never push the wheel pass 1200W so that I could go faster (it was about 6mph). I would expect this is doable as the max power is 3000W. It was set to Experienced riding mode. 

By doing the same, I could push the V8 up to just over 1400W and its speed was as fast as the ks16s. I even did the same test on an AirWheel X8, it could barely make it going slowly like a snail, at one point it was at about 1200W where it stopped. 

So I think the ks16s does not utilize the power of the motor. What is the point of 3kW max power when I am unable to use it? I think there is some improvement needed in the firmware here, like a Super Sensitive mode? @US69

Btw, this is just a test scenario to see how the wheels perform. I do not usually have that demand in my daily commute.

Has anyone done a similar test and been able to push the ks16s to over 1200W? 

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Try standing up straight and pressing the front of your foot like you are squashing a spider under your toes or putting a cigarette butt out without anyone seeing so you dont have to pick it up. This will force the pedals down better, and you wont overlean. The higher watt motors require different attenuation tactics on the larger wheels.

If you went into a pothole or over a 2 x 4 in the road, you could concievably get a higher spike to keep the vehicle upright, so maybe its better that you cannot reach maximum power by your force alone.

 

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17 minutes ago, Stan Onymous said:

Try standing up straight and pressing the front of your foot like you are squashing a spider under your toes or putting a cigarette butt out without anyone seeing so you dont have to pick it up. This will force the pedals down better, and you wont overlean. The higher watt motors require different attenuation tactics on the larger wheels.

Haha, I will try this technique but I can imagine that it would make my feed tired going for a long, hilly road?

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Peak power quotes are mostly an advertising trick. Stay with basic physics. The KS16S has a 1200w motor and a 840wh battery. Let's simplify and say that the battery starting at full capacity can putout 840w for about 50 minutes, 1680w for 25 min, and 2520w for about 17 min and 3360w for 12 min - draining down to about 20%. The motor is rated at 1200w, that is what it can put out optimistically for as long as the battery can supply the power. In reality the battery and motor will heat-up when run at maximum rating 1200w for a significant period of time. The controller mosfets will heat-up, and the wires carrying the current will heat-up. This heat-up process is magnified greatly if the motor, battery, controller, wires are subject to higher "peak" values. Manufacturers like Inmotion, Ninebot, and King Song, program what limts will be placed upon the wheel. Gotway allows for the user to decide, which can often lead to burn't out circuits. ESK8 manufacturers are famous for throwing out 4000, 5000, 6000w peak power claims or more with batteries rated 36v at 150wh.:whistling: Peak power claims are usually justified with oscilloscope wave forms showing instantaneous peak values for usually less than a second. Clear as mud ;) ? The short answer is KING SONG is not going to let you burn up the wheel trying to go up a steep grade at maximum speed.

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2 minutes ago, MouseWithoutBorders said:

Haha, I will try this technique but I can imagine that it would make my feed tired going for a long, hilly road?

Lol you only really need to do it when you are accelerating. When you are up to cruising speed, you can mix it up a bit.

Think of sailing as an example. The crew members will sit on a pontoon that needs stabilizing, but if the are going to lean out they are attached to a sling which is harnessed to the mast. You use the hull and the mast to leverage your force. On a wheel, you only have one connection to the vehicle, so at some point the lean becomes inefficient, as your tests showed, without the second connection for the triangle of leverage.

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Try the medium riding mode, it might help you get more momentum. Also try standing a bit more forward, so that the rear ends of your shoes are level with the rear end of the pedals.

I passed 2000W several times every time I rode.

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21 minutes ago, Stan Onymous said:

Lol you only really need to do it when you are accelerating. When you are up to cruising speed, you can mix it up a bit.

With this steep hill I could not even get to 10mph even pushing hard on the pedals constantly as the wheel never gave more than 1200W.

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44 minutes ago, MouseWithoutBorders said:

With this steep hill I could not even get to 10mph even pushing hard on the pedals constantly as the wheel never gave more than 1200W.

The motor has the maximum power output at about half the maximum possible speed (no load max speed ~ lift cut off speed).

Like shown here:

torquepowerspeed.jpg

At low speeds the efficiency is quite bad (high currents induce high losses on the ohmic resistance of the motor coils). Also this high currents lead to high power dissipation at the mosfets - so normally all this wheels have current limitations to protect the motor windings and electronics (and by this lower a bit more the possible power)

Additionally the power shown by the app could be way off (much too high). My assumption is, that the wheels just measure the motor current and multiply this with the battery voltage, but at the motor the voltage is much lower at lower speeds. (Very) presumably it was like this with the KS16C and "older" GWs. Inmotion (at least the V10) also measures the battery current. From the other new wheels no details are known (at least not to me)

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7 minutes ago, Chriull said:

The motor has the maximum power output at about half the maximum possible speed (no load max speed ~ lift cut off speed).

Like shown here:

torquepowerspeed.jpg

At low speeds the efficiency is quite bad (high currents induce high losses on the ohmic resistance of the motor coils). Also this high currents lead to high power dissipation at the mosfets - so normally all this wheels have current limitations to protect the motor windings and electronics (and by this lower a bit more the possible power)

Additionally the power shown by the app could be way off (much too high). My assumption is, that the wheels just measure the motor current and multiply this with the battery voltage, but at the motor the voltage is much lower at lower speeds. (Very) presumably it was like this with the KS16C and "older" GWs. Inmotion (at least the V10) also measures the battery current. From the other new wheels no details are known (at least not to me)

That's much better than my "muddy" explanation. I "assume" the apps read peak power which could be very high for a second or two, but very misleading. (Probably deliberate). The greatest disservice manufacturer do is post maximum speed, range, and power as if they could occur simultaneously, like go up a steep hill at maximum speed.

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So just this afternoon I rode a KS-16S up a 20% gradient at 20+ km/h (12+ mph) for over a kilometre.

  • Battery was at 75% of 640 Wh
  • Riding weight was ~118 kg (260 lb)

So you should be able to get more too...

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Wheels can't limit themselves (like max speed or max power), or you'd fall on your face as soon as you reach the limit. I suspect the problem is you don't push the wheel more.

Stand on your toes to go up a steep hill, or clench the wheel between your legs, or grab the shell with your hands and push down on the front of it - you just need to tilt it forwards somehow. But don't kill your wheel, if it's struggling and barely going forwards despite tilting it, that's too much.

It's a question between whether you just don't tilt it enough, of if it's too much for the wheel. But at 1200W power output, it must be the former.

I agree with the others, don't trust wattage number too much, be it in some app or the motor wattages. If anything, look at the current, so you know before a fuse blows (not sure what fuses the 16S has - 30A, 40A?).

@Jerome That's not how batteries work, they are limited by current output. The 16S is 4P (4 parallel configs of 16 cells in series) and with 10A max continuous per parallel cell block, the max continuous power at full battery is 4*10A*67.2V = 2688W. Can easily be much more for a short spike, though.

-

TLDR: If that 1200W number is true (where do you read it?), it's not the wheel, it's you.

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6 hours ago, MouseWithoutBorders said:

With this steep hill I could not even get to 10mph even pushing hard on the pedals constantly as the wheel never gave more than 1200W.

Don't be too eager to go up hill quickly. There are two possible negative effects:

1: wobble.  I climb a smooth paved steep hill regularly, and because of my Big Foot Pedals I maintain some speed.  I have noticed that wobble always sets in (more of a fast weave) until I consciously slow down.  I put this down to my center of gravity being quite a bit forward of the contact patch of the tire; creating an unstable  castor configuration, like a shopping cart with a bad (bent shaft) wheel.

2.  Sudden voltage sag due to pothole, bump, etc.  When your wheel is putting out a steady, high current, there is less reserve capacity for sudden power demands.  If you did manage to use up more that the 1200W indicated (accurately or otherwise) you would be putting yourself closer to the face plant zone.

Surely 10mph is a pretty good pace up a steep hill, whatever "steep" is in your book.

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1 hour ago, meepmeepmayer said:

Wheels can't limit themselves (like max speed or max power), or you'd fall on your face as soon as you reach the limit. I suspect the problem is you don't push the wheel more.

What meepmeepmayer said is trure.

 Also the KS16s is the same size yet heavier than the V8.  That means that you will have to compensate for the additional weight when leaning past center of gravity. (watch video)

 My wife is learning to ride. When we go up hills she struggles and complains. I  remember doing the same.  Now I go up the hills with hardly any effort and can't figure out why it was so hard for me in the beginning. 

 

 

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2 hours ago, RockyTop said:

What meepmeepmayer said is trure.

 Also the KS16s is the same size yet heavier than the V8.  That means that you will have to compensate for the additional weight when leaning past center of gravity. (watch video)

 My wife is learning to ride. When we go up hills she struggles and complains. I  remember doing the same.  Now I go up the hills with hardly any effort and can't figure out why it was so hard for me in the beginning. 

 

 

I love the more than 2cents table. Is that where you gather the folks to give them your advice? “Well everyone thats my two cents.”  ?

I forgot grabbing the wheel with your knees as in the KS18S which is tall enough to grab by the handle and the knees.

Your pedal length explanation is the reason why the V10F pedals are so genius. You can reposition your feet easier without the sandpaper grip holding your feet where you dont want them to be. They are larger too, and that is the vehicle that the stomp your foot onto the front of the pedal technique came from. A heavier friend used that technique very successfully so he wouldnt overlean. He said it was the only way to get the V10 to accelerate for him.

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4 minutes ago, Stan Onymous said:

I love the more than 2cents table. Is that where you gather the folks to give them your advice? “Well everyone thats my two cents.”  ?

6324 cents. When I made the table I had to go to ten banks to get the coins.  They would only give me $10 each and I rejected a third of the coins.  I thought I could glue them to the table in three or four hours and then pour the resin.  It ended up taking 30+ hours then another 8 hours tending the pour.  I listened to Nickel Back on my blue tooth speakers the whole time and only now caught the Irony of it. (Nickel Back)  Not sure if it was the pennies or Nickel Back or the lack of sleep but I almost lost my mind. ( Or maybe that is when I lost my mind or would have lost my mind if I still had it to lose.)

F4C3C417-BC58-4340-84A3-994CF8BF9EE7_zps

B66D790E-3D9C-4140-B338-4A22B49685D8_zps

before resin

6B2782D6-4F37-4351-9822-B123A4D70B8C_zps

70C14C32-708E-4E90-AB8E-7B9630202DC5_zps

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Thanks everyone for your responses! even though I don't quite get all of them as some are very technical detailed:)

My logic as a rider is as simple as: Since I can easily get other wheels to draw more than its nominal power (assuming there measurement is correct:)), I would expect I can do the same with ks16s, of course under its safety limit (battery, main board, motor). So I am probably asking for a more sensitive riding mode to be added to the setting. This is only for a rare scenario riding a very steep hill! I do not think I can find a road in my city that the ks16s would disappoint me actually!

Btw, I took the wheel to Vancouver Celebration of Light on Saturday night, rode around the busy English Bay for many rounds and got so many wows like "what is that thing", "I wanted that for my next birthday", etc... This would be a free advertisement for KingSong:) if my wheel has the big Sing Song symbol/logo printed on one of its sides as shown on ewheels.com like other riders have as well. My wheel just has its both sides black empty. I did not report this to Jason as it does not matter for me much but I am just curious if it was a mistake in factory assembly @US69?... After the fireworks, I was riding back in the dark to the parking lot pulling a wagen with three kids in it along a mile trail, up to a steep hill, the wheel was pretty strong!! Pulling a wagen with full of kids in a park is another best use of my wheel besides commuting:) the kids love that and would fight for a spot!

I feel 1200W is already a lot, I wonder if the advertisement "1200W continuous" is true for the whole wheel itself or just the motor? I feel if we push the wheel to 1200W constantly, it would overheat in few minutes. But KingSong engineers would have done this test:) I was trying my best leaning on the wheel and pushing hard again a wall for a few secs but unable to get more than 1000W out of it, meaning 1200W is quite a lot!!

 

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  1. People complained about the KS logo! So @Jason McNeil has his wheels come with logo-less black sidepads. This is supposed to be an upgrade. I wouldn't mind the KS logo as well.
  2. 1200W is just the motor number. According to Jason, in general such numbers aren't reliable as the motors overheat eventually, despite nominal or continuous meaning the opposite. So in the end, they just don't mean much (and aren't comparable as the Ninebot One Z shows), just give a general idea how strong the wheel will be.
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1 hour ago, MouseWithoutBorders said:

I was trying my best leaning on the wheel and pushing hard again a wall

Don’t do that! If you stress the wheel when it doesn’t move, the electric current is the highest. That is the easiest way of burning the control board. Perhaps not the easiest on the 16S, but I wouldn’t risk it!

For the same reason the wheel feels like it almost chokes if you ride on roots, curbs and other obstacles very slowly. The motor has the most power at around 20km/h.

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1 hour ago, MouseWithoutBorders said:

empty. I did not report this to Jason as it does not matter for me much but I am just curious if it was a mistake in factory assembly @US69?... After the fireworks, I was riding back in the dark to the parking lot pulling a wagen with three kids in it along a mile trail, up to a steep hill, the wheel was pretty strong!! Pulling a wagen with full of kids in a park is another best use of my wheel besides co

Nope that was no factory mistake ...

That was more or less a mojority decision to get rid of the ‘ugly’ big fat KS logo at the sidepads! as always controversial.....

It ist still imprinted on the pedals...it is on newer wheels on top! 

Personal i also didnt like the big KS advertisement on side...and ewheels.com was so nice to send me some without branding!

Now my 18S is just serious black all over....when people ask me: I always say which brand is reliable!!!

 

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1 hour ago, MouseWithoutBorders said:

feel 1200W is already a lot, I wonder if the advertisement "1200W continuous" is true for the whole wheel itself or just the motor? I feel if we push the wheel to 1200W constantly, it would overheat in few minutes. But KingSong engineers would have done this test:) I was trying my best leaning on the wheel and pushing hard again a wall for a few secs but unable to get more than 1000W out of it, meaning 1200W is quite a lot!!

And perhaps one advice....or tip:

Instead of having a look at some questionable numbers of the app...my tip would be to -whenever you meet someone with a higher announced wheel like a 1500Watt.....change with him and try it out :-)

The announcement of Watt numbers is sometimes more or less marketing...

 

If you follow my tip you will see that the 16S will outperform some of its higher announced competitors with ease!!

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On 8/4/2018 at 2:00 PM, meepmeepmayer said:

Wheels can't limit themselves (like max speed or max power), or you'd fall on your face as soon as you reach the limit

This.

That is the whole point of a wheel self balancing. The user decides to move the center of mass (since it can) by leaning forward and then the wheel has to counter this by accelerating. The wheel can't accelerate less than what is needed to counteract your new center of mass, because you would faceplant. So if it is not going past 1200W (which is already a lot) it must be because your mind doesn't feel like leaning even more. Your body is intelligent and protects itself :D

When we have a tiltback, that is a wheel accelerating MORE than what it needs to counteract you leaning forward, so it goes "faster than you", and then it has to brake (which was the whole point). So first accelerates such as your center of gravity goes backwards, that makes you lean backwards, and then brakes to regain your balance.

tiltback sometimes is like putting off a fire with some fuel

and my 2 cents

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5 hours ago, Struck said:

it must be because your mind doesn't feel like leaning even more

That is the point! Why would I need to work so hard when going up a steep hill, if the hill is long my feed would get tired. So all I ask is a more responsive riding mode:)

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On 8/9/2018 at 7:16 PM, Truong Do said:

That is the point! Why would I need to work so hard when going up a steep hill, if the hill is long my feed would get tired.

Again, because of laws of physics. I would re-read the post you replied to even more carefully.

On 8/9/2018 at 7:16 PM, Truong Do said:

So all I ask is a more responsive riding mode:)

KS wheels have three riding modes that have a good variance in responsiveness. I’d try a softer mode, as it lets you arrive in a stronger lean before correcting the balance.

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13 hours ago, mrelwood said:

, because of laws of physics. I would re-read the post you replied to even more carefully.

It seems the more replies I have the more I look stupid? But let me try one more time: So on my daily commute I have about 1km part that the wheel is almost at a constant state (10mph, 800W) where I have to lean constantly also like putting 100lbs on the front of the pedals. So all I ask is a change in the firmware so I would only need to put 50lbs to get the same performance of the wheel. 100lbs or 50lbs are just my estimated numbers but you know what I mean? I can work around this to have a better up hill cruising experience by shifting by feet forward so I do not have to lean but I would loose balance from doing that easily. 

This is about how to improve the wheel to have a better riding experience, not much about riding skills. I can ride for long time, go backwards easily, go down 3, 4 stair steps np, one leg, slalom/free style, etc. 

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