Inmotion & Solowheel

[Mono]

11 hours ago, Slaughthammer said:

But the KS16s has a 50% more powerful motor, that's something!

Verified how? Motor power wattage numbers taken from different manufacturer have IMHO a good chance to be not comparable at all.

It is also interesting to keep in mind that motor power and pedal length are the limiting factors for the effectively delivered torque. On my V8, I have been running into the pedal length limitation (that is, in a steep climb my weight is moving beyond the tip of the pedal), but so far not into the motor power limitation (that is, the pedal tip cannot resist and gives in under the weight applied to it).

[Slaughthammer]

We're talking about power, not torque. How much power you need to outtorque the pedals depends on a few variables: speed, rider weight, pedal length. For a heavier rider you need at same speed and pedal length more torque to lift the pedals underneath him. At higher speeds, you need more power to generate the same torque (power=torque*rpm). So maybe you don't need that extra power, but there maybe someone who is heavier and likes to go faster who actually can benefit from that.

[meepmeepmayer]

Comparison pictures from Jason/ewheels, apparently made to justifiedly shit on the Solowheel offerings (found in another thread, see here). Gogo Kingsong!

[WARPed1701D]

$100 price drop on the 16S too. Was $1475 just a week or two ago.

[Pagsy]

I got attached to  the cut engine button below the handle that you action when you lift the wheel.... 

[Mono]

On 30/07/2017 at 2:15 PM, Slaughthammer said:

but there maybe someone who is heavier and likes to go faster who actually can benefit from that

sure, I was only talking about me and that any extra power would be a waste of material and energy in all the use cases I have experienced so far on my V8 at about 80kg. And it's true that I am very reluctant to push forward at, say, 25km/h with all the weight I have to figure out whether the wheel can still push back and won't give in at this speed.

The general point remains though: for any given pedal length and rider weight there is a limit over which increasing the motor power only adds entirely useless weight to the wheel.

[Slaughthammer]

3 hours ago, Mono said:

The general point remains though: for any given pedal length and rider weight there is a limit over which increasing the motor power only adds entirely useless weight to the wheel.

Totally agreed! But I'd probably set that point a bit higher than you, but that's just personal taste.

(and just to be the miserable German smartass I am, it's actually pedal lenth in relation to wheel diameter and pedal hight... just a minor detail )

[Mono]

On 30/07/2017 at 2:15 PM, Slaughthammer said:

We're talking about power, not torque.

AFAIK, correct me if I am wrong, there is a direct (linear) relationship between torque and power. Everything else being equal (in particular speed), doubling power means doubling torque and vice versa, hence saying "I am running out of power" (or have plenty of it) is equivalent with saying "I am running out of torque" (or have plenty of it). 

From the riders perspective torque seems to be the more useful concept to think of, as it translates more directly to the weight displacement on the pedal (counter torque, if you like).

[Slaughthammer]

Let me explain this by quoting myself, from the same post that you quoted from:

On 30.7.2017 at 2:15 PM, Slaughthammer said:

(power=torque*rpm)

however, running out of power does no necessarily mean running out of torque. you could also be running out of speed (or rpm), for example, while accelerating with a constant rate, the power needed will rise with increasing speed, while the required torque will stay constant. (F=m*a, whereby m is considered constant for an EUC rider, and F is directly proportional to torque via wheel diameter) As torque output capabilities of EUCs reduce with increasing speed, this won't go on for very long...

Also interesting is, that max torque is limited by max current through the motor, whereas power is limited by current and voltage. So if you raise the battery voltage and don't increase the maximum current, you get more power from the motor, but not more torque!

 

(Further interesting physics: w=F*s, p=dw/dt. work is force times distance and power is work per time: If you push something heavy for a certain distance, you actually do work, if you manage to do that within a certain time period, you have a power output. That's basic Newtonian mechanics)

[Mono]

13 hours ago, Slaughthammer said:

however, running out of power does no necessarily mean running out of torque.

yes, it does. When the wheel still provides plenty of torque to accelerate or brake or whatever you could possibly do with it, you cannot reasonably claim to "run out of power". Running out of power and running out of torque are equivalent.

[Chriull]

14 hours ago, Slaughthammer said:

 

however, running out of power does no necessarily mean running out of torque. you could also be running out of speed (or rpm), for example,

Running out of * always means that the current needed for the asked torque cannot be provided anymore.

Limits for the current are:

- the battery voltage (max available voltage). The max voltage (in combination with the motor characteristics) also limits the max speed.

- the max motor power is not sufficient. The motor limit are mainly thermal or magnetic. These limits can be again "transformed" to a current limit.

- the controller/wiring cannot support any higher current.

Quote

while accelerating with a constant rate, the power needed will rise with increasing speed, while the required torque will stay constant. (F=m*a, whereby m is considered constant for an EUC rider, and F is directly proportional to torque via wheel diameter) As torque output capabilities of EUCs reduce with increasing speed, this won't go on for very long...

Correct, but unfortunately many (new) drivers are quite surprised by this...

Quote

Also interesting is, that max torque is limited by max current through the motor, whereas power is limited by current and voltage. So if you raise the battery voltage and don't increase the maximum current, you get more power from the motor, but not more torque!

You're assuming a different motor with the raised battery voltage, so that the max current==torque stays the same and just power is increased (higher speed possible)

With the same motor and increasing the battery voltage max speed, max power and max torque would be raised (as long as the motor survives)

 

[Tomek]

14 hours ago, Slaughthammer said:

Let me explain this by quoting myself, from the same post that you quoted from:

however, running out of power does no necessarily mean running out of torque. you could also be running out of speed (or rpm), for example, while accelerating with a constant rate, the power needed will rise with increasing speed, while the required torque will stay constant. (F=m*a, whereby m is considered constant for an EUC rider, and F is directly proportional to torque via wheel diameter) As torque output capabilities of EUCs reduce with increasing speed, this won't go on for very long...

Also interesting is, that max torque is limited by max current through the motor, whereas power is limited by current and voltage. So if you raise the battery voltage and don't increase the maximum current, you get more power from the motor, but not more torque!

 

(Further interesting physics: w=F*s, p=dw/dt. work is force times distance and power is work per time: If you push something heavy for a certain distance, you actually do work, if you manage to do that within a certain time period, you have a power output. That's basic Newtonian mechanics)

in my uneducated opinion, you're neglecting the fact that the max torque of a BLDC motor is not euqal across all speeds, and is 0 at top rated speed.

edit:

also, IMO, the motor can exceed the max rated continuous or peak power draw (and deliver more torque), but that's dangerous for the motor  so that's why the controller has to limit it...

[Mono]

16 hours ago, Slaughthammer said:

So if you raise the battery voltage and don't increase the maximum current, you get more power from the motor, but not more torque!

Which kind-of contradicts the equation you gave previously making a direct link between mechanical power and torque, namely

    power = torque * rpm

The equation tells us that, at a given speed, we can not get more power from the motor without having more torque.

[Slaughthammer]

4 hours ago, Mono said:

Which kind-of contradicts the equation you gave previously making a direct link between mechanical power and torque, namely

    power = torque * rpm

The equation tells us that, at a given speed, we can not get more power from the motor without having more torque.

I didn't state speed is constant. You didn't do that either before this post. In the real world, speed changes all the time. Why should it be constant?

 

6 hours ago, Chriull said:

You're assuming a different motor with the raised battery voltage, so that the max current==torque stays the same and just power is increased (higher speed possible)

With the same motor and increasing the battery voltage max speed, max power and max torque would be raised (as long as the motor survives)

No different motor. The same motor will with the same current limitations but higher supply voltage have the same max torque but be able to maintain that to higher speeds, thus be able to produce more power. If the max current is only limited by the available voltage, then your second sentence is correct. But in that case max current would then be not constant as stated by me and thus my statement would not apply. I assume, that at least for lower speeds, max current is limited by the capabilities of the MOSFETs. So on the actual speed/torque curve we get, starting from zero probably a steep rise in torque, then a plateau, at which the controller limits the max current and then a steady decline, in which the supply voltage limits the max current. If we increase the supply voltage, but don't change the controllers limitations, then max torque won't increase, it will just be delivered up to higher speeds, thus more output power.

6 hours ago, Tomek said:

in my uneducated opinion, you're neglecting the fact that the max torque of a BLDC motor is not euqal across all speeds, and is 0 at top rated speed.

In my uneducated opinion, you have not properly read what I wrote, but let me highlight the sentence you were missing:

21 hours ago, Slaughthammer said:

As torque output capabilities of EUCs reduce with increasing speed, this won't go on for very long...

 

6 hours ago, Tomek said:

also, IMO, the motor can exceed the max rated continuous or peak power draw (and deliver more torque), but that's dangerous for the motor  so that's why the controller has to limit it...

This is true for any electric motor... so how does this influence our discussion? 

Well, if we go back to the root of this discussion, the original question was: Is a higher power rating in any means relevant to the rider? We had two opinions, with Mono stating, that he can't outtorque his 800W wheel due to the pedals being to short, so why should anyone want more power? And I am still in the opinion that it's not that easy, and that while he may not need more power, there quite certainly are riders, for whom this will not be true. We digressed a bit.

[WARPed1701D]

Inmotion & Solowheel...

...as in the complete bastardization of Inmotion by Solowheel in the US and Shane Chen's possible plan for global EUC domination through being a spineless patent troll on a concept he didn't even invent.

Just a reminder of the thread title.

[Mono]

2 hours ago, Slaughthammer said:

I didn't state speed is constant. You didn't do that either before this post. In the real world, speed changes all the time. Why should it be constant?

I did, I said, even twice "Everything else being equal (in particular speed)..." and "The equation tells us that, at a given speed,...". Why? Because it doesn't make sense to compare (running out of) torque at one speed with (running out of) power at another speed. And because torque and power are not the same but (only, well, you actually can't expect any more than that) directly linearly related. So if you change other parameters in the setting of course you would expect to possibly get different changes for different measures like torque and power. Though it turns out that speed is the only parameter for which this is the case.

2 hours ago, Slaughthammer said:

with Mono stating, that he can't outtorque his 800W wheel due to the pedals being to short, so why should anyone want more power?

I think you are quoting me in a misleading way. I explicitly made clear that I was taking about my experience and not assuming that the same is true for everybody else or even anybody else (though it is quite likely that at least some riders do have the same experience). I obviously have an answer to the question "why should anyone want more power" and never would have even considered asking it.

2 hours ago, Slaughthammer said:

And I am still in the opinion that it's not that easy, and that while he may not need more power, there quite certainly are riders, for whom this will not be true.

Agreed that there are likely to be riders out there for which my observations do not hold. I never wanted to (and did not, as far as I can tell) suggest anything else. I don't even want to suggest that this will be true for me in any foreseeable future. I only know it has been true for me so far, as stated in my first post about motor power in this thread.

[Justina]

On 30/07/2017 at 0:36 AM, Mono said:

The 16S is heavier and wider and (I believe) has less ground clearance than the V8. I find these are significant disadvantages. What are its advantages besides a larger range?

The lower the pedals, the lower the centre of gravity. Thus the wheel can handle skids better. When it's raining, you can slip when turning sharp on the V8 without a proper tire, while on KS-16S you will be all good.

Higher pedals make the learning process a bit easier, the wheel is more "stable", and it's almost impossible to scratch the pedals when making turns. However, that makes the V8 less agile and more potent to skid. 16S is much more agile and it's not significantly wider. Additionally, V8 is much higher, which makes it hard to put into any backpack, in contrast to the KS-16S.

I love both the 16S and the V8. Both are great. I wish KingSong had the same designers Inmotion has, as the V8 is just beautiful, and despite the lower price it looks more premium. KS-16S has better performance and equipment (the twilight sensor is just awesome, it's almost perfect) - I prefer this one because of a better riding experience. But if someone is on the hunt for a bit cheaper wheel - and also a better looking one - the V8 is also excellent and its performance is actually all you need. In my opinion, these two are the best all-riders on the market right now.

[Mono]

@Justina, the lack of pedal clearance has become lately the main reason of unexpected falls driver-wheel-separation incidents for me, even on the V8. One pedal (or the foot) catching something on the ground (e.g. the edge of a pothole or a curb or a stone) is an event from which it is very hard to recover without separating from the wheel. Of course, when only riding on perfectly flat ground this is a non-issue, but that's not how the world looks like I am riding in. Hence pedal clearance has become for me a major safety issue and I don't think I would ever buy a wheel again with less than 13cm clearance, maybe even 15cm.

On the other hand, the limited tire choice for the V8 I see indeed as a major disadvantage of the wheel.

On 04/08/2017 at 7:18 AM, Justina said:

16S is much more agile and it's not significantly wider.

Do you by any chance have the width measure of the KS-16S?

[person5555]

Honestly, this is just depressing. At first, when I saw an ad on YouTube I thought "Hey, maybe InMotion is finally advertising in the US. This will be great for the EUC market in the US!" 

And then I scrolled down, saw "Solowheel" on the ad info, and lost all hope. 

Now I'm just hoping that the same thing doesn't happen to Gotway or Kingsong. (I can already picture it now, $2,400 Gotway ACM or $3,750+ Gotway Monster )