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bennelson 01-09-2008 09:54 PM

Electric Motorcycle conversion
1 Attachment(s)
EDIT: January 2018. I have posted ALL of my original BUILD YOUR OWN ELECTRIC MOTORCYCLE DVD as YouTube videos. They are divided into sections. The following playlist is the full and complete collection of the OFFICIAL video that I made based on this project.

[Author's note, added September 2014.]
It's been going on seven years since I built the motorcycle. I've learned so much working on this project, leading me to also build an electric car and a hybrid. I also now give presentations teaching people how to build their own electric vehicles. When the motorcycle was complete, including a 48V battery pack and welded battery rack, I created an instructional DVD set teaching how anyone can build their own. If you are interested, please take a look at the DVD on my blog at: It's also now available as a digital download as well.
Have fun reading this thread. It was a blast to learn how to build an electric motorcycle!
-Ben Nelson 9/24/2014

PPS: Apple computers discontinued their web page service, simply deleting the original web page that I created on this project. Because of that, there are some broken links and missing images in this thread. For the latest on this project, please visit

(Begin original post)

Last summer, I converted an old, non-running motorcycle to run on batteries and an electric motor.

It has sort of been a tinker-along-the-way project. I have never had a motorcycle before, but always wanted to learn to ride. I also hated how loud motorcycles are. (Shouldn't they call them ENGINE-cycles!?!?)

I had tinkered around with an electric bike, which was great fun, but then I wanted more speed and shocks. I was also suprised at how car drivers behaved around the electric bicycle. People would pull out right in front of me not realizing how fast I was going.

I sort of figured that if I wanted something that was faster, better suspension, and street cred, that thing would be a motorcycle.

I took a good look through the Austin EV Album to see what parts people commonly used on small projects and e-mailed a few folks for advice.
I picked up a copy of the "Secrets of EL Ninja" book/plans and used it as a rough basis for the conversion.

I wanted to do eveything as cheaply as I could, but I did buy a new Alltrax controller and later, new Yellow Top batteries in place of the tiny AGMs I was using from the bicycle.

The cycle is completely street legal, licensed, registered, and insured.

It was only designed as a short-range/limited speed project, mostly because of what I could fit in it for batteries. It goes up to 38 MPH and the longest I have ever taken it is about 16 miles, with just a little break and tiny bit of charging between the two 8 mile one-way trips.

Both my office and the grocery store are only about two or three miles away each, so even this limited range is plenty.

It's a blast to ride. Easy to steer. No clutch, no engine to kill or restart, just twist the grip and go. It is also quiet. There were a few times I would just hop on and zip off to the grocery store. When I got back, my wife would never know I left because the thing is so sneaky quiet. (yeah yeah - loud pipes save lives. Don't get me started. I may just have to hook up an iPod running engine rev noise or stick a baseball card in the spokes. Maybe use a bicycle bell like on that one crazy Commuta car.)

The motorcycle is stashed in the garage for the winter. I would like to eventually work on a cheap, simple, 4 wheels and a roof vehicle for getting around in non-motorcycle weather. (Yes, another Forkenswift....) I am in Wisconsin - motorcycle season isn't that long.

So basically the cycle runs at 36 volts - I would like to bump it to 48 sometime, just need to find space for one more battery...
It goes 10 to 15 miles on a charge which uses about a kilowatt. That comes to about a penny a mile. I figure if gas is $3.00 USD per gallon, that means I get 300 miles per gallon! (I've also done the math completely based on energy content using a conversion from M.I.T. When I did that, my first ride clocked in at 321 miles per gallon equivalent.)

SVOboy 01-09-2008 10:12 PM

Sweet job! I demand more pictures...I'm extremely jealous...


bennelson 01-09-2008 10:47 PM

3 Attachment(s)
I spent about $2000 on this project all together.

$100 for original cycle
$500ish for motor (used on Ebay)
$300ish for New Alltrax AXE 48v 300 amp programmable controller
$160 EACH for 4 Optima yellow top 55AH batteries.

I am also including in this total cost, a motorcycle safety class, new helmet, a year of insurance, lots of little trips to the hardware store, etc.

I am still trying to figure out how to fit that last battery in there.

Here are a few more photos.

bennelson 01-09-2008 10:56 PM

Here is the link to the info I have posted on the EV Album.

MetroMPG 01-09-2008 11:39 PM

Awesome. Thanks for posting that.

Ben's site is cool. More pics & info, neat design. Check it out:



It goes 10 to 15 miles on a charge which uses about a kilowatt.
Your 15 mi / kWh = 67 wH per mile. Nice!

The best I've achieved on a charge cycle with the ForkenSwift is 311 wH / mile.


Question: what type of DC/DC converter did you get? We have one but haven't installed it yet, partly because of winter, and partly because it didn't come with installation instructions (but looks similar to yours with the pins sticking out the back).

If all you need is short range & 35 mph, have you considered shopping for a Citi/ComutaCar? Or are you also looking for another project?

MetroMPG 01-09-2008 11:44 PM


Originally Posted by bennelson (Post 4758)
I am still trying to figure out how to fit that last battery in there.

  • If you know someone who can weld, I've seen people reshape the frame in such a way that you could put another one ahead of the lower single battery.
  • Or, you could do battery "saddle bags", gomi style. (You have seen the gomi bike, right?)


MetroMPG 01-09-2008 11:47 PM

PPS: you know to keep an eye on your ETEK brushes, right? I've read they wear quickly compared to most motors, and if you let them get too low you can damage the commutator.

Silveredwings 01-09-2008 11:54 PM


Originally Posted by MetroMPG (Post 4772)
Or, you could do battery "saddle bags", gomi style. (You have seen the gomi bike, right?)

" butta" :thumbup:

bennelson 01-10-2008 12:24 AM

I would rather stay away from saddle bags. for one thing, it means you need to add two batteries, and I only need to fit one more.

My controller only supports up to 48 volts, so I max out at four batteries anyhow.

Since the cycle is working and registered, I don't have to worry about a state trooper inspection or anything. Maybe I could look at welding and bending the frame. I personally don't weld or have a welder. I would rather not pay a professional welder either.

Hmmm... which of my friends has a welder...

If I do any welding on this, I would also do up some real battery mounts at the same time then. Plenty of bed frames down at the local thrift store.

Now if I can locate a cheap 72V controller, I can add the 4th batt AND do saddle bags.

No I havent' checked the brushes lately. I will have to do that in the spring before I get riding again.

Daox 01-10-2008 09:38 AM

You could remove one battery from the engine area, move it to a saddle bag, then add the 2nd saddle bag for 4 total. Or, you could ask me to help out and I could probably take care of that welding for you. I'm no professional, but I can put two pieces of steel together (some of my work). I doesn't look like it would be hard to extend the very bottom a few more inches for another battery to slide in there.

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