Voltage Fueled Electric Motorcycle

72V Curves, Tysonic, Charger, Motor, Deployed PV 3-D models

2009-09-17T19:56:00.000-07:00

September 17, 2009

I have several updates today:

The Factory Service Manual is on backorder and I would still rather wait for it before beginning to disassemble the gasoline power train.

I discovered another sealed lead acid AGM battery option from Tysonic that is significantly cheaper than B&B and fits perfectly into the available space. It would provide similar range as the Lithium Ion pack I am considering, at one third the cost, but its life may be up to a tenth shorter than Lithium Ion and the range will suffer degradation throughout the batteries life. LiFePO4 is still the better value. I also created models of the new battery option, battery charger, motor, and deployed PV panels. See the video for more detail.

Todd Kollin at http://www.electricmotorsport.com/ and John Fiorenza at http://www.marselectricllc.com/ were very responsive in emailing me the 72V performance curves for the Etek-RT (ME0709) motor I will be using. I haven't yet studied the curves in detail to begin my performance estimates and to select the proper gearing and top speed targets.

Testing 45Deg PV Panel Concentrator

2009-09-13T18:54:00.000-07:00

September 13, 2009

I tested the first version of a concentrator to increase the power output of the photovoltaic panels. The concentrator consisted of 4 white pieces of foam core board set at 45 degrees to the panel surface. I set the panel outside in my backyard facing due South and at 32 degrees with respect to the ground. Thirty two degrees is the optimal angle for my location in September. I took measurements of panel voltage and current throughout the day to calculate power (Power[watts]=Volts X Amps). Measurements were taken with and without the concentrator in place and I compared power levels to see the effectiveness of the concentrator. I found that the concentrator produced shading early in the day and late in the day. As a result of the shading, power output turned out to be lower with the concentrator in place even though it did help to increase power near noon. I confirmed the shading issue with a 3-D sketchup model and will use sketchup to help redesign the concentrator with a better angle to eliminate shading. The redesign of the concentrator will include:

Concentrator set at a lower angle based on Sketchup shading simulation (likely between 30 and 40 degs)
Surface of concentrator painted with high gloss white paint to increase reflectivity
Improve mounting system of foam core board to PV panel

Front Tire and PV Panels Arrived

2009-09-12T15:20:00.000-07:00

September 12, 2009

The new front Bridgestone Battlax BT45 tire arrived yesterday and was installed this morning. I can finally stop fearing the front tire will blow every time I get on the bike. The two 30watt photovoltaic panels also arrived, appear to be functional, and the dimensions were as listed. I will be performing some measurements on the panels tomorrow to start estimating the added power that may be attainable by using some white reflective panels to concentrate sunlight onto the panels a bit. The service manual is still not in and obtaining Texas plates and safety inspection sticker is still pending. Batteries seem to have a long lead time of 6 to 10 weeks from the lowest cost supplier so I will likely hold off on beginning the dismantling of the bike until a few weeks before the batteries and motor are expected to come in. The Google Sketchup model I showed in my previous post gave me confidence that there will be enough room to mount a 69.3Volt battery pack in the available space so I feel I can order batteries without more precise measurements with the engine removed.

3-D Model of Battery Pack with Google Sketchup

2009-09-10T19:55:00.000-07:00

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

Photovoltaic Panel Cardboard Mock-up

2009-09-07T19:55:00.000-07:00

September 7, 2009

I made a cardboard mock-up to help me start to plan and visualize how I will mount the photovoltaic panels. There seems to be enough room and solid mounting points to attach the panels sturdily and reliably. I am not convinced that exisiting solar charge controllers will work well for my application which requires using a low voltage solar array to charge a high voltage battery pack. I also want the ability to use a battery pack that is not necessarily in increments of 12 volts as current charge controllers are designed for. Having to design and build a custom charge controller will take a bit of time and research on my part, which means the photovoltaic portion of the project will take a bit longer than I had hoped. Freeing myself from the constraints of charge controllers on the market allows me to start with a higher voltage battery pack, however, and I am now thinking of going ahead with a 66V or 72V pack. Friday will be a big day as the new front tire, photovoltaic panels, and factory service manual should come in. As soon as I get the new front tire installed I will start removing the internal combustion powertrain components.

Battery Technology Selection

2009-09-06T13:50:00.000-07:00

September 6, 2009

I've been researching different battery types after finishing reading the "Secrets of El Ninja" motorcycle conversion guide. The guide was published in 2006 and it compares different battery technologies as they stood in 2005. The three technologies I was considering were 1)sealed lead acid (Absorbed Glass Mat), 2)flooded lead acid, and 3)lithium iron phosphate (LiFePO4).

I'm discarding the thought of using flooded lead acid. I don't like the idea of a tipped bike spilling Sulfuric acid all over itself and potentially the rider. The constant need to monitor water levels is also not my idea of maintenance free EV bliss. Sealed lead acid or flooded lead acid were the only economical options for conversions until recently. In 2005 the cost of a 4.1kWh lithium based pack would have been over $8000! Pricing in 2009 is now a little over $1300 for a 4.1kWh lithium pack and is very close in price to a comparable sealed lead acid pack.

It now seems that the logical choice is to go with a LiFePO4 pack. I've decided to start with a relatively low voltage pack, 48Volts, using Thundersky LiFePO4 batteries, http://www.thunder-sky.com/home_en.asp. EV Components is the company that currently has the best pricing on LiFePO4 batteries, http://www.evcomponents.com/SearchResults.asp?Cat=34. Chinese battery makers seem to be the only ones currently selling Lithium Ion based batteries in low volumes to U.S. distributors for the conversion market.

A total of fourteen, 3.3Volt Thundersky batteries are required for approximately 46.2Volts, but what amp-hour capacity to choose? Once the system voltage has been decided upon (46.2V), the amp-hour capacity has to be chosen based on the range needed. I need a minimum of 36 mile roundtrip range in case I cannot plug in at work. The two formulas in "Secrets of El Ninja" for estimating range are 1)best case at 30mph on flat ground with no wind, 2)stop and go range:

BestCaseRange = kWhrs x 9.8 miles/kWhr Where kWhrs is (pack voltage) x (battery Ah)

StopAndGoRange = kWhrs x 7.0 miles/kWhr

I analyzed the range for various Thundersky batteries from 40Ah to 150Ah and found that to meet my range target with 48Volts I need to use the 90Ah batteries or greater.

An issue with battery sizing is that I will likely increase the voltage in the future as funds allow. Increasing voltage improves range much as increasing amp-hour capacity can. At higher future voltages I could get away with a greater number of smaller, lower amp-hour batteries for the same range. I will be making some 3-D models to determine what the best battery size is with future expansion in mind.

Using hypermiling techniques, http://www.cleanmpg.com/, and based on my commute route, I estimated my range as the average of the two formulas above. A unique feature I will be adding in my conversion is two 30Watt photovoltaic panels as rear fairings that will be able to tilt up into position at the correct angle while parked. These two panels I estimate will add about 3.5 miles of range based on the following formula:

AvgSolarMiles=Watts x Derating x AvgSunHrs/1000 x AzimuthOptimizationFactor x miles/kWh

60 x 0.85 x 6.53/1000 x 1.064 x 9.8 = 3.5 solar miles

The Azimuth optimization factor adjusts for the fact that being able to adjust the panel angle will help increase power production throughout the year as the position of the sun changes with the seasons. I would also like to add a concentration feature to increase output further and will experiment with concentration once the panels come in.

Inspecting my purchase

2009-09-03T16:19:00.000-07:00

September 3, 2009

My initial test ride confirmed the brakes, suspension and wheels are in good shape. The bike only has 6400 miles but at 23 years old, age has taken an aesthetic and functional toll on some parts of it:

Front tire needs immediate replacement due to cracks in sidewall and minimal tread left
Loose front, right foot peg

Scratches requiring paint on forks, frame, fairings, brake lever, fuel tank

Faded front right side fairing

Small spider cracks on one gauge lens but not very visible

Crack near one fuse cover mounting hole

Cracks in some fairings

The front tire is my first order of business. It is a critical safety feature and I have felt very uneasy riding the bike with the front tire in its current condition. Tires are limited in 16”, bias ply sizing, but for the commuter intentions of this bike, I’m not looking for the latest and greatest race rubber. I ordered a Bridgestone BT45 from http://www.motorcycle-superstore.com/ today. The bike currently has a BT45 mounted and I have had a good experience with past Bridgestones on both cars and motorcycles.

The brakes feel weaker than my other bike, a 2006 Honda VFR800, but that was to be expected. I believe there is nothing wrong with the VF500’s brakes; my first motorcycle was a 2006 Ninja 500 of similar design vintage to the VF500 and the brakes felt very similar.

The rear shock in VF bikes of this era is known for being a common failure point. Both front and rear shocks use air for either damping or as a spring and the rear seals are failure prone. A much more reliable CBR shock can be adapted, but the custom work runs to close to $300. Anyhow, the rear shock on this bike does not seem to have failed yet. The air pressure range for the rear shock is 7 to 21 pounds and is currently set at about 18 pounds. The previous owner is heavier than I and had described the rear suspension as “bouncy” which led me to believe the rear shock was bad, but bumps are damped well at my lower body weight. I may try a bit higher pressure to see how it feels, but at this point, I don’t believe the rear shock is bad.

I had initially thought of immediately removing all the fairings and sending them off to be repaired and painted, but I have decided to patch and touch them up initially. I will later take on the painting task myself, especially since it looks like I will need to trim or modify some of the fairings in the back for my “surprise” feature. Learning to paint and repair plastic panels will be a bonus learning experience.

I have ordered the Clymer’s Service Manual from http://www.oldbikebarn.com/ and will wait for it to arrive and the new tire to be installed before beginning the removal of the engine, transmission, exhaust, cooling system, and stock battery. I’m a big fan/believer of factory service manuals. I do not want to damage any parts during removal as I may use them for another project or will offer them for sale online.

Why a 1986 Honda VF500?

2009-09-01T20:13:00.000-07:00

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.

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.
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.
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.

Why electric? Why a conversion?

2009-08-30T12:07:00.000-07:00

August 30, 2009

Why an electric motorcycle? I’ve become attracted to the idea of electric propulsion for several reasons:

An electric drive train is very simple. There are on the order of 50 parts for an electric drive train versus 500 parts for an internal combustion one.
Reduced emissions improve the air we breathe and reduce the effect of human transportation on the environment.
Driving electric reduces dependence on foreign energy sources.
A motorcycle makes more sense than a car or truck due to the low weight and resultant higher performance and lower cost.
Reduced maintenance time and cost stems from the elimination of liquid cooling, oil based lubrication, liquid fueling, and brake wear (if regenerative braking is incorporated).

Why a conversion?

Enough of a quality supplier base for conversion components now exists.
Many have treaded down this road by now and one can build on and learn from their experiences.
The learning experience is priceless compared to buying a readymade electric vehicle.
There is a risk of buying an electric motorcycle from one of the many current startups that may end up bankrupt, leaving customers without support. By building my own, it will be easier to debug the system since I will be intimately in tune with the components and how they were put together. Once the big 4 motorcycle companies (Honda, Yamaha, Suzuki, Kawasaki) start producing electric motorcycles, conversions may make less sense depending on OEM pricing.
Help recycle and older, unloved motorcycle.
It will be lots of fun! Right?

Below is an image of the donor bike I have selected. The purchase is in process; the agreed upon purchase price is $875 and I have left a deposit for the bike to be held while I transfer funds from one account to another to be able to pay for the bike in cash. I'm excited to get started on the project and the transfer should only take 2 to 3 business days. I will go into more detail about why this particular bike was selected as a donor in my next entry.