ElectroCat lithium battery powered motorcycle
Hi,
I just recently read about this (A123) lithium battery powered electric motorcycle, and it looks freakin' awesome! Eva Håkansson - with passion for electric drive http://iloapp.evahakansson.se/data/w...1244517903.jpg http://iloapp.evahakansson.se/blog/w...1223746668.jpg http://iloapp.evahakansson.se/blog/w...1231773036.jpg Quote:
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Cool, I'm expecting one of those brushless eteks soon, though the lipos are gonna have to wait I'm afraid.
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What is it about electric vehicles that makes people not want gears?
Seems like a transmission will give you the ability to trade between speed and acceleration. I think that is why gas/diesel engines do it. I am just curious why (besides extra weight and mechanical loses) that most of the EVs seem to forgo any transmission. I also think I have read where an advanced motor that is wound in such a way that the windings can be switched around, basically changing the way the motor works (effectively getting a transmission built into the electric motor)? If this above is all true, then with the small size and compactness of motorcycle transmissions, why not keep it? |
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A couple guys on this site use 2nd and 3rd for their EV's because they motors are underpowered. |
I think the mechanical simplicity is very appealing, there are losses in a transmission, but just a chain to motor can be very efficient. But a gear or two would come in handy if it were efficient and inexpensive and not too bulky for a motorcycle.
I've been wrestling with some two speed ideas, hoping to avoid bulk/expense/losses. It gets a little complicated when you add those parameters in. A motorcycle trans is not compact, after you shoehorn batteries and motor and whatnot on the bike. It is also overkill, the torque curve of an electric motor doesn't benefit from all those gears, only a couple are needed, and the extra gears are just spinning and turning your electrons into heat. What I was thinking of was a motor with a through shaft, a bike with two sets of sprockets and chains (different ratio on each side), and a clutch on each end of the motor to engage that side, and maybe a one way sprag on the low speed rear sprocket so that you don't have to turn both chains while cruising in exchange for a loss of low speed regen performance. EDIT, my ETEK showed up today :) |
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dunno, maybe 2:3 or 1:2? It should be easy enough to try different combos of sprockets and find something that works the best, depends on taste to some degree I'm sure.
But if it takes, say 18 seconds to reach 60mph with a single gear, an additional lower gear that is 2:3 the ratio should be able to top out at 40mph and give 50% better acceleration up to 40mph, which would ideally knock 4 seconds off the 0-60 time, maybe. a low gear that is 1:2 the ratio would top out at 30mph and knock off maybe 4.5 seconds, kinda sorta. |
Thanks!
I didn't think you needed the 6 gears that some bikes have, but was thinking 2 or 3. |
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