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The EVMaine Electric Car Project Blog - Page 1 of 4 |
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By Bill Drinkwater / EVMaine.org
I am working on the car again. . I want a relatively inexpensive electric car, so I will build it. Construction will take several months. I will keep a planning and construction diary, starting on this page. So you can follow the design decision-making processes, if you like, and the construction stages as they occur. There will be many photos included. Expect a lot of rambling statements and opinion-changing until the dust settles on the final design decisions along the way. And even they will change as I build it. Sorry, but that’s the way my creative process works. I design-as-you-go. That means backtracking occasionally, and redoing something as I change my mind about how to proceed. This entire blog is being repeatedly revised, so you might want to occasionally reread it from the beginning. First I must decide on the basics of my vehicle.
Design Criteria Purpose: A one-person car that I can use to run local errands, to drive for fun and to take to car shows, schools, environmental and alternative fueled vehicle shows and to my PowerPoint presentations to meet like-minded people and to promote this website, and its mission of informing Mainers about their options concerning electric vehicles. Hopefully my car will have a range of about 40 to 50 miles per charge, and will probably have a top speed of between 40 and 50 mph. Spring/Summer/Fall driving only/no heater needed. Open cockpit with (eventually) a removable hardtop which will be a 110 watt Mitsubishi solar panel. . Although I can garner some very good design ideas from solar racers, my vehicle will weigh hundreds of pounds more than any of them because of its steel frame and six 12 volt lead/acid batteries that will weigh close to 50 pounds each. Exotic high tech batteries that are used in solar cars only weigh about 5 pounds each, but they currently cost far too much for me to consider. Also, the carbon fiber material that they use for their car body is extremely light, but it is also too expensive and high tech for me to use for my car body, not to mention the $100,000 worth of solar cells on the body of them. I may use thin sheet aluminum for my car body, but fiber panels or fiberglas seems more likely. My car should cost no more than four thousand dollars by the time it is finished. I’ll include one small solar panel to trickle charge the auxillary battery that feeds the lights and horn. My car will have to be highway-legal. I live on a highway with a speed limit of 45 mph where I live, so I cannot drive a Low Speed Vehicle around here, also known as a Neighborhood Electric Vehicle, to get to town (5 miles away) because they cannot be driven on roads with a posted speed limit higher than 35 mph. A 3-wheeled vehicle would weigh less than a 4-wheeled vehicle. Since vehicle weight is extremely critical in electric vehicles because they must run on very little energy, my choice is to build a 3-wheeler. A 3-wheeled vehicle must be registered as a motorcycle in Maine even though it will look more like a 3-wheeled soapbox derby racer with two wheels in front and the drive wheel in back. Toad and Delta are the two shape names for 3-wheeled cars. A toad has the two wheels in the front, while a delta shape has the two wheels in the back. Mine will be a toad design. The two wheels on front has proven to be more stable, especially on corners. Photos of over 160 3-wheelers are found at this URL: http://www.3wheelers.com/projgall.html Although most of them are gasoline-powered, they show many interesting and innovative body and running gear designs. My car will have a safety glass windshield, and a windshield wiper. It will have LED taillights and turn signals to reduce consumption of electricity, and a bright headlight or two with both high and low beams. I want the vehicle to be unique enough to attract attention to the EVMaine.org logos that will be painted on its sides, so I cannot buy a kit car because that would look too much like all of the other kit cars. Instead I will build a vehicle from scratch with a totally unique design. Why not just buy some books on how to build an electric car? Because they tell how to convert a standard car to electric, which is very different from building a simple, usable, small electric car from scratch. For starters, a standard car has a very heavy steel frame and a heavy steel body that requires a powerful motor and electronics, and therefore needs lots of very heavy batteries to move it. Mine will have a smaller and more lightweight steel frame. My little peawee car will be much simpler to build, and I think it will be a lot more fun to drive, than many larger electric cars.
The ill-fated Sinclair C5 (British). Once touted as THE great personal tranportation breakthrough for the UK, it proved to be too small, too weak and too dangerous in traffic. http://www.speedace.info/sinclair_c5.htm
Safety Features to be Included Safety is a major concern for me, so it will have disk brakes on all 3 wheels, a horn, a steel roll bar, a seatbelt, break-away side mirrors on both sides, a recessed door handle, a rear view mirror, a backup light, a backup alarm, a passenger-side door only, and a hand-operated (emergency) brake. Safety bumpers front and rear with air-filled boat bumpers. Inertia switch (cuts power automatically in case of an accident) A high voltage kill switch. It will have larger diameter wheels than are usually found on a small car which will make it safer and more comfortable when negotiating potholed roads. The relatively low speed and proper front end geometry should prevent ‘scrubbing’ or sliding (loss of traction) of the narrow front tires on corners.
I like this basic design
http://www.youtube.com/watch?v=2hX7DWtnLBc I will use six flooded lead/acid deep cycle marine batteries for 72 volts total. The car frame will have nine inches of ground clearance, but must still have a center of gravity as low as possible to deter rollovers, so the batteries will be placed as low as possible. . The driver’s seat is a very comfortable passengers seat from a junked ‘99 Dodge Caravan. It will have all-wheel suspension so the vehicle won’t be bone-jarring to drive on mostly side roads in the real world. The two front wheels must have fenders of some sort, probably plastic. Wheels: 26.5 inch sturdy spoked wheels with Kevlar belted tires on front and a slightly smaller diameter, but heavier single motorcycle tire in the rear, which will be the back end of a motorcycle frame with a highly modified fork. Relatively narrow tire treads will reduce rolling friction and thereby help to increase the vehicle’s range per charge. This is a 3-wheel design that I like, but mine will be much taller.
My vehicle will have a top speed of most likely around 40 to 50 mph, as measured by an electronic bicycle speedometer. It won’t have a transmission since small electric cars don’t need one for such relatively low speeds. That will help keep the vehicle weight to a minimum. I will be running a 72 volt, DC system. That translates to six, 12 volt, 125 amp/hr lead/acid deep cycle batteries onbooard. It’s a lot of weight, but necessary. DC motor systems tend to be much simpler and cost less than AC motor systems, so I’ll have a DC system. Despite what many experts recommend, I have decided not to have regenerative braking in my vehicle. I will include a small solar panel to keep the extra battery for the car lights and horn topped off. The dash will have an electronic speedometer (bicycle-type), a Curtis battery ‘fuel gauge’, an ammeter and whatever other instrumentation and switches are deemed necessary. I will put some lightweight, noise-reducing foam between the driver and the motor/chain drive. The car will have a square steel tubing frame. A more unconventional body material could be fabric stretched over an aluminum tubing body frame. That would be almost weightless. http://www.mit.edu/activities/solar-cars/flash/vehicles/present.shtml An absolutely superlative solar car blog with LOTS of useful information is below: http://www.stanford.edu/group/solarcar/equinox.html A lockable compartment for groceries, an onboard charger, etc will also be included. The car will be painted either bright yellow so that it will be more visible in traffic for safety. Basically, a light color, not a dark color will also be physically cooler than darker colors in a warming climate. I will paint it myself using a good quality brush. Here are two quirky 3-wheeled designs from Italy that are somewhat appealing, to me at least.
My car will be tall enough that people in regular vehicles will know that I am in the traffic mix. I will sit upright in the car over the battery box, so the car will be taller than recumbent vehicles. Wheelbase: Looks like around seven feet. Width of Body: The body is only 24 inches wide at its widest (the driver compartment). The front wheels are now 45 inches wide. In/Out: A grab handle on the dash. Ignition: I’ll get a key switch and contactor. I’ll run all wires in plastic conduit. Although this will be a one-person vehicle, it must also include enough room for a couple bags of groceries in a locked compartment so the car has some real utility. It will have an extension cord and charger onboard for “opportunity charging” wherever possible in any 110 volt grounded AC outlet. Trailering: I will get an eight foot long trailer for taking it more than 30 miles from my home. Towing: I will attach sturdy tow hooks on the ends of the frame. Here’s a somewhat similar design concept: http://www.mcn.org/a/omni/elite/elite.html
This is the Pod One 3-Wheeler from www.gaiatransport.com
Other Considerations Where will I build it? I am building it in my backyard in Summer 2008. How will I pay for this project? I will sold my 2003, 250 cc Honda Reflex scooter. Its been a lot of fun, but it is time to move on to this new project.
Do I have adequate skills for this project? I have done much mechanic-type work and repairs on my own vehicles over the years (before vehicles became too high tech to work on), and have designed and built many of my own projects, including several RVs. I had a job building prototype safety cars for a company with a contract with the U.S. Department.of Transportation many years ago, hence my preference for safety features. I also was an arc and oxy-acetylene welder for many years. I have only a few hand and power tools left, but I won’t need many for this project. I also have a smalll cored wire-feed welder to use on this project. However, I am NOT using any exotic tools or techniques on this car that anyone who can hold a hammer in their hand cannot easily do. What is my budget for this project? $4,000 max, hopefully only $3,000. The electronic motor controller and other electronics jack up the price considerably, putting it closer to the $4,000 mark, unfortunately. Next Page: I’ll start selecting the components needed after much research and studying on the Internet.
Let us know how you would do things, or have already done things differently. We will publish your comments as we receive them.
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