3-D Model of Battery Pack with Google Sketchup

September 10, 2009

Google Sketchup is a wonderful, easy to use, free tool for doing 3-D modeling of everything from small mechanical components to entire buildings. I used it to make a 3-D model of the battery space available and various sizes of battery packs. I took measurements on the stock bike with the engine in place so I will have to refine the model when I take the engine out and can get more accurate measurements with nothing in the way. It looks like I will have enough space to even mount the battery pack in a stylized V-shape in honor of the V-4 soon to be removed. Mounting the packs in straight flat rows would be quicker and easier but I'll study the feasibility of the V-shaped mounting once I have the batteries in hand and an empty chassis to work with. I compare various pack sizes in the following video and show how they would look mounted in the bike. You can download sketchup and tutorials on how to use it at: sketchup.google.com

Why a 1986 Honda VF500?

September 1, 2009

I chose the Honda VF500 as a donor bike for several reasons (one certainly was that it was the best candidate on my local craigslist):

• The VF500 has a relatively lightweight chassis at 406 pounds dry. Some modern sportbikes are lighter, but not by much. Light weight is key in an electric conversion to minimize size and weight of motor and batteries required for a specific target performance and range.
• Narrow tires are good for aerodynamics and reduced rolling resistance. The back tire is in great condition with lots of tread but the front is quite worn and cracked requiring an immediate swap out for fresh rubber.
• The front, square cross-section, boxed, steel frame should make supporting batteries, motor and related electronics a much easier endeavor. Minimal welding should be required.
• The center stand will greatly facilitate development and testing.
• I’m a big fan of Honda vehicles in general and have had very good experience with their reliability.
• The upright ergonomics, suspension tuning, and practical front fairing make for agile, comfortable travel in daily commuter duty.
• An open front frame allows a design that will show off the batteries.
• The VF nomenclature provides a wonderful opportunity to say it’s “Voltage Fueled”!
• It met criteria I was looking for in any bike: under $1k target price (paid $875), brakes and suspension in good condition, minimal crash damage and salvageable aesthetics from minor drops or scrapes

I considered 3 other bikes as donor bikes.

1. I looked at a Kawasaki ZX-11 that I would have had to ship from Wisconsin. The bike was rideable but had a faulty 3rd gear in the transmission which is not important in a conversion to single speed EV drive. The ZX-11 is a heavier bike, with no front lower support frame, and less commuter friendly ergos, but with better suspension and brakes. There is at least one other ZX-11 already converted, http://www.tronbikes.com/ by Todd Stiers in Berkeley California. Todd was very willing to answer some of my questions as this project began to take shape in my mind. I actually made a deal with a sales guy in Wisconsin for the ZX-11 but it fell through when he found out someone else had just put down a deposit for the bike. I would have exceeded my budget considerably due to shipping costs from Wisconsin to Texas. With shipping, the price would have been $1399 and in the end I feel the VF500 is a better EV candidate.
2. A 90’s Yamaha YZ750 was a second candidate for $1000. It had front brake issues and a salvaged title, which made me question chassis integrity. Additionally it suffers from some of the other cons the ZX suffers from: weight, frame design, and ergos.
3. A 90’s Kawasaki ZZR600 was a third candidate also for $1k. The owner did not do a good job of getting back to me to answer my questions and send pics. The owner of the ZZR eventually told me it was used strictly as a stunt bike so I can imagine it was pretty beat up.