# Newbie with performance questions



## kaisersozay (Jul 25, 2008)

Disclaimer: The extent of my knowledge about electricity begins and ends with "don't stick your finger in the wall outlet." Having said that, here is my situation.

Other Disclaimer: I have a passion for motorcycles that extends back to when I was 4 years old. Words simply cannot express the love that I have for these two-wheeled beauties. Cruisers, sport bikes, standards...I don't care, so long as it has 2 wheels and a motor.

Combining my passion for motorcycles with soaring gas prices prevalent in the U.S. right now, electric motorcycles seem like a good avenue to pursue.

I simply can't find an electric motorcycle with the performance comparable to a 750cc or 1000cc motorcycle (or even a 600cc for that matter). I don't want a glorified scooter. I want to have all the benefits of an ICE bike (performance) with the benefits of an electric bike (no gas/oil, little maintenance, all the stuff you already know).

My goal - build an electric motorcycle that accelerates like a 750cc (or preferably a 1000cc) ICE motorcycle. Range should be around 20-30 miles (give or take). And it shouldn't look like a crap covered brick. Finally, make this bike for the same $$$ that it's traditional counterpart would cost.

Ok - now for the questions:

- What would it take to build an electric motorcycle that can accelerate like a 750cc ICE motorcycle? I'm talking about batteries, voltage, motor, etc...

- With all the buzz about A123, why can't you just split apart a few DeWalt 36V packs and create your own pack? It'd wouldn't take too many of these to really get into the higher voltage side of things, plus they are small and lightweight so mounting them shouldn't be an issue.

- What controls acceleration? The controller? The number of volts?

- And now, for quite possibly the most ignorant question ever posted to this (or any similar) forum. If performance is all about voltage, why hasn't anybody used rechargeable 9V batteries? They're cheap, rechargeable, small, lightweight, and easily replaceable. What am I missing here?

Again, this is all new to me so please be gentle with your replies. 

Thanks for your input!

Kaiser


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## joseph3354 (Apr 2, 2008)

what you want is readily achievable,if you have the proper budget.
as to the 9 volt batteries,it may be that they do not have a weldable configuration like the cylindrical cells. welcome to the forum!


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## kaisersozay (Jul 25, 2008)

joseph3354 said:


> what you want is readily achievable,if you have the proper budget.
> as to the 9 volt batteries,it may be that they do not have a weldable configuration like the cylindrical cells. welcome to the forum!


Thanks for the welcome!

Here is my thinking/justification for the budget. If I'm willing to spend $6K-$10K for a gas-powered bike, why not an electric one? Plus, I won't have to pay for gas, oil-changes, etc... It sounds logical to me - now all I gotta do is convince the wife that it's a good argument.  (wish me luck)

So - is it reasonable to think I could build this bike for $6K - $10K?

About the 9V...what if a wiring harness could be developed? Something that has the typical 9V "caps", but with another set of wires coming out of the "caps" that would lead to the next 9V battery? If such a harness existed, could I have a copper-top powered motorcycle?


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## frodus (Apr 12, 2008)

> I simply can't find an electric motorcycle with the performance comparable to a 750cc or 1000cc motorcycle (or even a 600cc for that matter). I don't want a glorified scooter. I want to have all the benefits of an ICE bike (performance) with the benefits of an electric bike (no gas/oil, little maintenance, all the stuff you already know).


where have you looked? Take a look at EVAlbum.com , and look at some of the sportbikes. 

My website is www.evfr.net, have a look at what I've done. Mine accelerates like a 400-500 with used batteries and stock rear sprocket. Ordered a sprocket to change from a 4:1 ratio to a 5.5:1 ratio. Roughly a 37% increase in torque, which will help in acceleration. Right now with my motor limited to pack voltage of 72, It hurts speed. Once I go with my 144V pack, it'l go much faster. Most people remove the transmission because its built into the engine... if you can fabricate you can install a CVT or another transmission to get the gearing you need. You won't find many motors that are above 30Hp to fit in a 750 size bike, and if you did, you'd need lots of amps to get the torque you want, and lots of volts to get the speed you want. Amps is Torque, Volts is RPM. Motors provide max torque at 0 rpm, so it'l outperform an ICE version for the most part. Top speed might be an issue due to the RPM limit of the motor being 5500 or so with DC, and with an AC motor, somewhere around 7500-8000.

As stated, performances is going to cost you. If you want that kind of performance, you'll likely be looking at AC sytstems starting around $2500, and a lifepo pack starting around $3000. You failed to mention range in your requirements, if you want performance, and have a limited budget, range will decrease. If you have money, you can spend more and get some A123 batteries, but realize, you're going to need a ton of them. they're about 80Wh for a dewalt pack. Now, you want to have good performance and get more than 10 miles right? so you'll need somewhere in the order of 3000Wh. Thats about 35 packs, and at over $100 a pop, thats over $3500 bucks, then you have to weld them, and install a balancer for each cell group, you're well over $4000. There are better solutions for lifepo.



> My goal - build an electric motorcycle that accelerates like a 750cc (or preferably a 1000cc) ICE motorcycle. Range should be around 20-30 miles (give or take). And it shouldn't look like a crap covered brick. Finally, make this bike for the same $$$ that it's traditional counterpart would cost.


Range is doable, but with the performance you want it might cost a pretty penny. At this point, AC, with lifepo (you don't want it to be a lead weight with sealed lead acid, and want performance). It doesn't have to look like crap, take a look at my VFR:











> Ok - now for the questions:
> 
> - What would it take to build an electric motorcycle that can accelerate like a 750cc ICE motorcycle? I'm talking about batteries, voltage, motor, etc...


AC system, lifepo, lightweight chassis, and you'd be limited to about 84V, and 550A. That should get you pretty damn good performance. Robyn Lundstrom on Evalbum has a nice vehicle with that AC motor and Thundersky Lithium, take a look.



> - With all the buzz about A123, why can't you just split apart a few DeWalt 36V packs and create your own pack? It'd wouldn't take too many of these to really get into the higher voltage side of things, plus they are small and lightweight so mounting them shouldn't be an issue.


 You can, but you'd need tons of them to get what you require... at least 35, maybe 40.



> - What controls acceleration? The controller? The number of volts?


well, the current provides torque, the controller controls the current from the batteries as well as the speed of the motor. Essentially, the controller controls the acceleration, but the amp capacity of the batteries are the limiting factor, if you can't provide amps, you won't get the torque you need. 



> - And now, for quite possibly the most ignorant question ever posted to this (or any similar) forum. If performance is all about voltage, why hasn't anybody used rechargeable 9V batteries? They're cheap, rechargeable, small, lightweight, and easily replaceable. What am I missing here?


well, because they only have about 500mAh... 9V times 0.5A = 4.5Wh. Lets say you want 3000Wh, you'd need approximately 666 (hey, I didn't make that shit up) to get what you need. Then take away 25% because each one has connection losses, and it all adds up. Other batteries use welded tabs or screw terminals. Push in terminals don't provide good connection. You'd need tons of them, they would be bulky (666 of them takes up room), and you'd need a way to charge them. Plus, nicads are crap for performance and they gain a memory after a while, and have a short life.



> Again, this is all new to me so please be gentle with your replies.


Hope this helped


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## kaisersozay (Jul 25, 2008)

That's a nice looking bike! And thanks for the link to evalbum, too!

I've been cruising around on that site for a little while and found a good example of what I'm thinking about:

http://www.evalbum.com/1011

None of these numbers are tested, but from what they are expecting it sounds pretty good. I never even thought about using two motors until I saw this motorcycle. Maybe I'll try to contact the owner and see if he has any pointers.

Thanks for the input/links/advice! Keep it coming if you've got any more.


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