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On 5/10/2017 at 3:41 AM, 陈小杰 said:

In the latter part of the year, we will introduce more innovative models, and in the near future, I would like to hold a global game of players, it is not showing the skills of flower boxing embroidery, I would like to Kartson racing venues, and off-road venues, held a test Performance and rider technical events.

The aggressive styling and performance of the GT16 really appeal to me. If you could strike a deal with a reseller in the US for parts and warranty service that would definitely get me to buy.

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On 2017-06-05 at 8:53 PM, KingSong69 said:

70kmh?

really? i only can see that when driving with integral helm, full!! body protection, leather boots, handshoes, wristguards and so on...

When i would wear something like this...i would drive a Kawasaki 1200cc with 300horsepower...but not a unicycle!

my 2 cents...as long as there is no redundacy in the boards...no thank you!

 

 

Well, is that 70kmh holding the wheel in the air, or 70kmh under load? My guess is that it's the turn-off speed when the wheel runs unloaded. If so it's not THAT different from the original turn-off speed...

Much more interesting would be to see a torque-curve at higher speeds. Going 70kph seems like nothing I'd like to try without full armour, but higher max-speed might mean the torque stays OK at slightly higher speeds, which would feel good as a safety margin.

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6 hours ago, Scatcat said:

Much more interesting would be to see a torque-curve at higher speeds. Going 70kph seems like nothing I'd like to try without full armour, but higher max-speed might mean the torque stays OK at slightly higher speeds, which would feel good as a safety margin.

From the theoretical torque and power vs speed graph we can actually draw some conclusion. Assuming both motors have the same nominal power (which appears at half max speed) and lets call half max speed the nominal speed. Then the motor with lower nominal speed has more torque below its nominal speed and the motor with higher nominal speed has more torque above its nominal speed. The graphs cross somewhere in between, but there is no simple formula to understand the crossing point. An example with max speed at 50 (blue) and 70 (red), the nominal speed (speed at max power) is indicated with the black dashed lines, the linear lines indicate torque:

 torque-and-power-vs-speed.png.adf774572513b1128d5eb9f6df090acf.png

In short, the motor with the lower speed specification gives, relatively speaking, more torque at lower speed and less torque at higher speed. No real surprise there. The point is that we can specify the turn-around point given we know the specifications for power and max speed.

Edited by Mono

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1 hour ago, Mono said:

From the theoretical torque and power vs speed graph we can actually draw some conclusion. Assuming both motors have the same nominal power (which appears at half max speed) and lets call half max speed the nominal speed. Then the motor with lower nominal speed has more torque below its nominal speed and the motor with higher nominal speed has more torque above its nominal speed. The graphs cross somewhere in between, but there is no simple formula to understand the crossing point. An example with max speed at 50 (blue) and 70 (red), the nominal speed (speed at max power) is indicated with the black dashed lines:

 torque-and-power-vs-speed.png.adf774572513b1128d5eb9f6df090acf.png

 

Yoiu need to choose your terms appropiatly. Saying power and torque is not clear the way you are using it. I could say that you can not have the same Power and the Higher or Lower Torque. Power in lay terms is interpreted as how strong the motor is in terms of Torque so by definition you can not have a motor with same power and different Torque. Also Power is Watts. So do you mean they can handle the same Watts?

What conclusions you are talking about? What formulas are you talking about. I dont think you know what you are talking about.

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5 minutes ago, esaj said:

I think the amount of rounds and thickness of winding can be used to make motors with different torque vs. speed characteristics for same wattage. Gotway MSuper V2's had three different versions (High Speed/Low torque, usually referred to as "HS", a medium one, and high torque/low speed -version usually referred to as "HT"), which all had 1000W nominal power. The motors and mainboard firmware were different for each version, and to my knowledge couldn't be mixed (ie. the "HT"-board couldn't drive "HS"-motor correctly, and the firmwares weren't user updatable).

correct.

I^2xR .  thicker Gage wingdings is lower R and also Higher I. I and R are in Balance.  Watts are kept the same. And since you engineered higher current then your torque just went up also with the same watts.

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The blood is ankle-deep on the floor it seems...

Well, this exchange is why I was interested in the torque-curves. Is it the same windings and thereby a situation where the curve is moved upwards in speed and elongated, or is it a different motor with other torque-specifications? To be quite frank, I don't really give a s--t about more max-speed, but I am very interested in what speed is safely usable.

"Safely" in this context meaning where the rider won't face-plant because of a cut-off or insufficient torque.

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5 hours ago, Carlos E Rodriguez said:

I could say that you can not have the same Power and the Higher or Lower Torque.

You could say that, but you would be wrong ;) Power is torque (or force) times speed. The distinction between power [W] and torque is kind-of relevant. We have maximal torque at zero speed (where we also have zero power) and maximal power at half of the maximal speed (where we have of the maximal torque).

5 hours ago, Carlos E Rodriguez said:

Power in lay terms is interpreted as how strong the motor is in terms of Torque so by definition you can not have a motor with same power and different Torque. Also Power is Watts. So do you mean they can handle the same Watts?

Yes, they have the same nominal power in Watts. You didn't look at the graphs, I assume. They are the same as one on a page link you posted recently.

5 hours ago, Carlos E Rodriguez said:

What conclusions you are talking about? What formulas are you talking about. I dont think you know what you are talking about.

oh, thanks for the complement :smartass:. There is an option to hide posts from forum members of your choice from you. Go for it. I did too B)

Edited by Mono

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33 minutes ago, Scatcat said:

Well, this exchange is why I was interested in the torque-curves.

AFAIK this would be a first that an EUC manufacturer publishes their torque versus speed measurements sheets. Unfortunately. And if you would tell me they don't even have these kind of sheets, I would immediately believe you.

I would already be pretty happy if I would know the true nominal power and the true maximal speed (or nominal speed) of the wheels. I guess for some we do know, when they use ready-made standard motors.

Edited by Mono

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25 minutes ago, Scatcat said:

The blood is ankle-deep on the floor it seems...

Well, this exchange is why I was interested in the torque-curves. Is it the same windings and thereby a situation where the curve is moved upwards in speed and elongated, or is it a different motor with other torque-specifications? To be quite frank, I don't really give a s--t about more max-speed, but I am very interested in what speed is safely usable.

"Safely" in this context meaning where the rider won't face-plant because of a cut-off or insufficient torque.

To find the holy grail of safe speed. The world landscape is not a steady state. So we can start with theoretical:

  • The motor Back-EMF increases as the wheel spins. So the maximum RPM is when the Back-EMF is equal to the battery volts. Now by safe I mean in terms of current flow. When the Back-EMF is equal to BatteryVolts you have zero current flow and zero torque so never go there. Also the closer to that RPM you get there is less delta volts so less torque because of less current. Since we are talking about balancing a mass, then you need some marging in which you can induce enough current/amps to balance your body and overcome rolling resistance and overcome wind drag. all these assuming a flat surface. In this scenario (flat). I would suggest staying 20% below the theoretical BackEmf=Battery volts so you have some torque to keep the wheel balancing.
  • Going up hill is a different story. since gravity is pulling back. At low RPMs there is low BackEMF. This allow the controller to put maximum current to the motor. the rider can control the maximum current by been aware of how hard you are leaning of the wheel. Up to a point you can enter a hill at some high speed and you should be safe if you do not lean harder than when you entered the hill and not exceed max current risking a BMS shutdown. But if you feel you start to need to lean harder, you should not do that but instead bleed off speed progressively. But no so simple. You need to know the current limits and monitor in those situations. I would try to not exceed 50% of max to give me margin for surges when the wheel is trying to balance up hill. and Max current is what the BMS would shut you down at.

These is very simplistic and does not cover every condition or battery capabilities so dont shoot me yet.

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27 minutes ago, Mono said:

You could say that, but you would be wrong ;) Power is torque (or force) times speed.

Yes, they have the same nominal power in Watts. You didn't look at the graphs, I assume. They are the same as one on a page link you posted recently.

oh, thanks for the complement :smartass:. There is an option to hide posts from forum members of your choice. Go for it. I did too B)

I will never hide another user.  I just dont like speculation passed as knowledge. We can have opinions and that is great but we can not be making statements of facts based on non-sense.

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2 hours ago, Carlos E Rodriguez said:

I just dont like speculation passed as knowledge. We can have opinions and that is great but we can not be making statements of facts based on non-sense.

Right, I could't agree more! I mean, we can, but we certainly should not.

Consider that most people don't write non-sense on purpose, that is, they don't know that they write non-sense when they do. That is what conversations are for then, among other things, to figure out which is the non-sense and which is not. Often its just that the writer meant something different than the reader understood.

Edited by Mono

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Glad to see the blood getting cleaned away :)

 

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36 minutes ago, Carlos E Rodriguez said:

I just dont like speculation passed as knowledge. We can have opinions and that is great but we can not be making statements of facts based on non-sense.

But that's what I do half the time :P  Well, not really, I don't try to pass it as "knowledge" or "facts" when I'm unsure about things, that's why I use terms like "maybe", "might", "could", "best guess", "I think" etc. In case you have signatures disabled, this is what mine says, so I don't have to repeat it all the time:

While I discuss things like batteries, motors, electronics, physics etc. in these forums, I'm not qualified in these areas in any way (except for software engineering). I'm an amateur and a hobbyist, and my "knowledge" and conclusions (more like "best guesses") come mainly from reading and studying about these subjects, not that much from real world experience, and I could be wrong about things. I take no responsibility of any wrong information I may have (unintentionally) written or wrong conclusions I've made based on my limited knowledge or misunderstandings.

 

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2 hours ago, esaj said:

But that's what I do half the time :P  Well, not really, I don't try to pass it as "knowledge" or "facts" when I'm unsure about things, that's why I use terms like "maybe", "might", "could", "best guess", "I think" etc. In case you have signatures disabled, this is what mine says, so I don't have to repeat it all the time:

While I discuss things like batteries, motors, electronics, physics etc. in these forums, I'm not qualified in these areas in any way (except for software engineering). I'm an amateur and a hobbyist, and my "knowledge" and conclusions (more like "best guesses") come mainly from reading and studying about these subjects, not that much from real world experience, and I could be wrong about things. I take no responsibility of any wrong information I may have (unintentionally) written or wrong conclusions I've made based on my limited knowledge or misunderstandings.

 

You almost convinced me :) and now I vaguely remember why I disabled signatures...

Edited by Mono

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7 minutes ago, esaj said:

But that's what I do half the time :P  Well, not really, I don't try to pass it as "knowledge" or "facts" when I'm unsure about things, that's why I use terms like "maybe", "might", "could", "best guess", "I think" etc. In case you have signatures disabled, this is what mine says, so I don't have to repeat it all the time:

While I discuss things like batteries, motors, electronics, physics etc. in these forums, I'm not qualified in these areas in any way (except for software engineering). I'm an amateur and a hobbyist, and my "knowledge" and conclusions (more like "best guesses") come mainly from reading and studying about these subjects, not that much from real world experience, and I could be wrong about things. I take no responsibility of any wrong information I may have (unintentionally) written or wrong conclusions I've made based on my limited knowledge or misunderstandings.

 

Goddammit @esaj, you could probably run the disclaimer department of whatever software-firm you work for :D

 

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On 6/5/2017 at 3:04 AM, 陈小杰 said:

92.4V  944WH  88PCS 18650

Maximum speed 70KM
Has been tested for three months
 
 

IMG_4692.JPG

I want one. When will it be for sale?

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6 hours ago, kasenutty said:

43.x mph sounds sketchy on a 16. But I want one too :D

+1 :)

The new 92.2V version seems to use 22S packs. This is a 10% increase in voltage (and watts) from the existing 84V model. 

My 84V GT16 cruises comfortably at 35km/h (~200 Lbs) so the 92.2V version could probably cruise closer to 40km/h - unless they have made it as a high speed/low torque version for featherweight riders...

Edited by Lorents

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1 hour ago, Lorents said:

+1 :)

The new 92.2V version seems to use 22S packs. This is a 10% increase in voltage (and watts) from the existing 84V model. 

My 84V GT16 cruises comfortably at 35km/h (~200 Lbs) so the 92.2V version could probably cruise closer to 40km/h - unless they have made it as a high speed/low torque version for featherweight riders...

I kind of doubt they changed the motor at all... The control board has probably been modified to handle the increase in voltage, but other than that I think it's just more cells.

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48 minutes ago, lizardmech said:

I think everything on it was rated for 100V or more to begin with.

Probably. After all, it's just isolation, tolerances and spacing on the board. The components used will probably handle the voltage just fine.

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20 hours ago, swvision said:

I want one. When will it be for sale?

I have been looking at this wheel for three months and I think its going to be a winner. The price is just amazing but not buying yet. Maybe Christmas time. also quality issues might not be all out yet. Hopefully they put out a new model with fixed dimensions.

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18 minutes ago, Carlos E Rodriguez said:

The price is just amazing but not buying yet.

Sure about that price? Reports are the revisioned GT16 will cost more than the current GT16 listings, and the Wheelers Paris store GT16 page sure seems to reflect this.

Edited by houseofjob

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