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[kasul51]

Hello, My peer and I are Industrial Design students at Rhode Island School of Design (RISD) and have taken on the ambitious project of building an Electric motorcycle. We found your forum and are very impressed with the knowledge base you guys seem to have on the subject.

We are starting with a yamaha 1990 yamaha FZR frame. We have access to a very nice machine shop, vacuum forming, FDM rapid prototyping and a 3 Axis CNC machine (depending on how much funding we can get)

We are going to create a prototype bike using the FZR frame and custom fabricating most everything else.

Ideally we are hoping this prototype could achieve speeds up to 70 MPH with a range of 25 miles.

Although a lot of the project will  be based on the aesthetics and ergonomics of the EV We also need it to be functional.

So that being said, What are our options?

Lead acid verse lithium?

AC verse DC motor?

IS regen worth it?

What kind of controller is best.

Is belt drive worth it? (if we could CNC the sprockets from a cad file)

are there any up to date books on the subject worth buying?

Any help is greatly appreciated and we will keep the forum up to date on our progress!

Thanks in advance!

[frodus]

Hello, My peer and I are Industrial Design students at Rhode Island School of Design (RISD) and have taken on the ambitious project of building an Electric motorcycle. We found your forum and are very impressed with the knowledge base you guys seem to have on the subject.

Welcome to the forum!

We are starting with a yamaha 1990 yamaha FZR frame. We have access to a very nice machine shop, vacuum forming, FDM rapid prototyping and a 3 Axis CNC machine (depending on how much funding we can get)

Great frame. How many CC is the bike?

We are going to create a prototype bike using the FZR frame and custom fabricating most everything else.

Ideally we are hoping this prototype could achieve speeds up to 70 MPH with a range of 25 miles.

Completely possible to do.

Although a lot of the project will  be based on the aesthetics and ergonomics of the EV We also need it to be functional. So that being said, What are our options?

Not hard either, just don't change the frame a ton. Geometry of the suspension and wheels must stay somewhat the same if you want it to be functional.

Lead acid verse lithium?

Go Lifepo4 or Lipo. Both are cheap. Lifepo4 will last longer than lead and Lipo. Lead is heavy and doesn't give a ton out due to Peukert. Lifepo4 is what most people use.

AC verse DC motor?

If you want regen (which you stated), you'll either have to do Permanent Magnet AC (Synchronous) sometimes called BLDC, AC Induction (Asynchronous), Permanent Magnet Brushed DC, or Seperately Excited. AC and BLDC being the two most efficient of the bunch. I'd suggest either the Motenergy Double stack with Sevcon, or an HPEVS AC20 with 1238 controller (what I've got). I've been happy with my AC20.

IS regen worth it?

Is getting ~5% or more back (more range) worth it? If it's free, then sure. Some setups without regen end up costing just as much as their AC/BLDC counterpart in the end.

What kind of controller is best.

Not all are the same, There are some great brands depoending on what you're doing.... like Curtis, Alltrax, Sevcon, Zilla, Soliton.

Is belt drive worth it? (if we could CNC the sprockets from a cad file)

Not really. Not if you want to remove the swingarm every time you need to replace the belt. Belts are hard to find and spec, and if they're custom, you'll pay out the tail. Chain is pretty efficient, and if you have AC/BLDC, you gain some back from the high efficiency and the regen. You can always go back and do it later if you want, but I'd stick with chain, and get some nice o-ring chain.

are there any up to date books on the subject worth buying?

Yes, Carl Vogel's book and Ted Dillard's book.

Any help is greatly appreciated and we will keep the forum up to date on our progress!

Thanks in advance!

Good luck!

[gasdive]

I agree with everything Travis said.

I'd just like to add that the range on the Zero DS is about 30 km at mixed urban and minor highway traffic flow speeds when drained by about 90%.  It's very light and efficient.  It has a nominal capacity of 4 kWh but really about 3.5    I'd **guess** that you'd want a minimum of 6 kWh to get the range you want but I'd be thinking 8 would be better. 

=:)

[frodus]

no you don't need that much for 25 miles.....

The range on the new DS is about 43 miles/70km EPA with a 3.9kwh nominal pack, which would be about 90wh/mile.

~100wh/mi is about average for a our bikes cruising around the city at 45 and below.... so for 25 miles@100wh/mi you'll need 2500wh or so, since you don't want to go past 80% DOD, lets say ~3.1kwh total pack capacity, give or take some. I'd shoot for 4kwh to have some more capacity for hills.

If he's wanting to go 70mph AND get 25 miles, then you're up near 150wh/mi or slightly higher, 3750Wh @80%, total pack ~4.6kwh. Shoot for maybe 5kwh or so.



I'd shoot for at least 40 miles range at 100wh/mile average, or about 5kwh. The bike I'm in the middle of upgrading, should be between 5.1kwh and 4.6kwh (still figuring out how many batteries I can actually fit in the frame).

[gasdive]

I replied and somehow managed to put the reply in a thread that I've never read.

Basically what I said was that the epa tests done on a dyno might be ok for comparing different bikes, but don't seem to map well with what people are actually getting in the real world.  That doesn't surprise me as a dyno test is never going to replicate real world riding.  Not only is the real world much more complex, it has air resistance!

=:)

[electrc109]

www.diyelectriccar.com as well!