Kymco Electric Superbike.

Discussion in 'Electric Motorcycles' started by klaviator, Feb 18, 2019.

  1. klaviator

    klaviator Long timer Supporter

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  2. klaviator

    klaviator Long timer Supporter

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    Oops, There is already a thread on this.
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  3. voltsxamps

    voltsxamps Advolturer

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    Link below in case anyone needed a short cut

    https://advrider.com/f/threads/kymco-supernex-electric-bike-155-mph.1349324/

    An electric superbike coming from Kymco though, it’s worth mentioning twice :) Looking forward to hearing more about it; especially on their mated 6-speed gearbox. I rode Brammo/Victory’s Empulse with a 6 speed gearbox, so I’ve got some seat of the pants experience on what that feels like, as well as the pro and cons.
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  4. T.S.Zarathustra

    T.S.Zarathustra Been here awhile

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  5. ctromley

    ctromley Long timer

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    I'm not that thin-skinned, it's very hard to raise my blood pressure and I remain in good health. But thanks for your concern. My point was simply that people theorize (incorrectly) that a transmission makes as much sense on an EM as an ICE bike, which isn't true. The fact of the matter is that cost, packaging and performance are all better if you increase current limit and upgrade the other affected components, rather than adding a transmission. I went on a bit to explain why because some people respond to that. Others need to see for themselves. This is one of those things where the trade-offs are hard to see clearly going in. Just trying to help people make an informed decision on a rather expensive purchase.

    Anyone with experience on an Empulse TT care to comment? That would be the only real-world data that's available so far.

    And BTW, I fail to see how a trans might affect "electric bike power fade." That reads like marketing gibberish. Lithium is a very stiff chemistry, meaning it holds its power very well down to near-zero capacity and then falls off a cliff. That's dangerous for the battery, which is why most EVs won't let you get that close to zero. So "fade" is minimal, and changing gearing to mask it only encourages you to use more power when you should be conserving it so you can get where you're going. It's just an overly-strained justification for a trans.

    I agree that Kymco should build and sell the SuperNEX, with a trans. Then let the market decide. Maybe that will finally settle the question.
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  6. Madrodo

    Madrodo Adventurer

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    It has nothing to do with the power the battery delivers. It is about the torque characteristics of the motor. Electric motors have an extremely high torque from zero to about medium RPM, with the curve pretty much flat, then it begins dropping off steeply after that as counterinduction in the coils really begins to take its toll. This is unlike an IC engine where the torque keeps building with the RPMs of the engine, usually right up to the red line. The gears on the electric bike are actually there to keep the motor in the low to medium range where it is at 100% torque.
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  7. ctromley

    ctromley Long timer

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    You're not seeing the entire picture. What you say is true, but with electric power the motor is nothing but a dumb conduit for power. Design centers around getting good efficiency and thermal management. That's it. No black magic like variable cam timing, shower head injectors, exhaust power valves, etc. involved - just convert the electricity to motion without getting in the way and without melting. The power you can use depends primarily on the battery pack (how much horsepower you have), and the controller (how much of that power can be fed to the motor in a controllable manner).

    The controller is rated by its current limit, which is typically lower than the max available from the pack. So the motor can only work with - not produce - the torque (which is a factor of current) that the controller can provide, until it reaches the speed where back EMF in the motor starts limiting the current the motor can draw. (Which, incidentally, leads to a truly flat torque curve and linear power while in current limit.)

    So if you want power at high speed, you simply match your motor characteristics to a battery pack to give the power you want at the speed you want, with gearing to suit. Then set your controller's current limit for the amount of mid-range grunt you want. You can also get what you want by adding a trans in the mix (though 6 speeds is certainly mindless overkill - two is probably plenty). But when you investigate both options the trans generally loses for a variety of reasons. A big one is that a trans takes up space that could be used for a more powerful pack.

    How does a direct-drive EM work in real-world terms? I'm reading about 60 - 80 mph times in the 1 second range. The previous roll-on kings of the world were literbikes, which can only manage a measly, yet still eyeball-flattening 3 second 60 - 80. 80 mph is not slow. (Don't know about real top speeds, because they're limited by software. The Strike's performance profile, including a 150 mph top speed, will be interesting.)

    Want the same grunt and more power at higher speed? Gear it for higher speed and bump the current limit up. The highest current limit I've seen for a production EM is 775 amps. I have a 1000 amp controller in my basement. 2000 amp controllers are fairly common in performance EVs. This is not a leap of technology.

    I don't care how you get your power or speed. But I also favor solutions that make sense. If someone comes up with an EM that uses a trans, and actually riding that EM shows that there's a reason for it, I'm a fan. So far, no one has made that case. The economics and packaging don't favor it. Maybe cost rises faster than performance beyond 1000 amp limits. Maybe packaging works better with a smaller 2 speed trans. (Doubt it. You still have the clutch.) Kymco completely surrendered any claim to sensibility by making their trans a 6 speed.

    The one and only way that makes any sense is to attract ICE motorcycle riders who don't know anything about a how an EM works and figure you need a 6 speed trans on a fast bike. After they live with it for awhile, they'll realize they don't really need to shift at all, there's only a weak case to be made for maybe 3rd and 6th, but there's useless shifting between those two.

    I'm betting the 6-speed, 150 mph SuperNEX will pale in comparison to the 1-speed, 150 mph Strike. That's the comparison that will (hopefully) settle this issue.

    In theory, theory and reality are the same. But in reality, ....
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  8. T.S.Zarathustra

    T.S.Zarathustra Been here awhile

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