Electric Conversion

I was driving Suzy ( my 2002 GEM eS) around an abandoned parking lot overgrown with weeds when I noticed a Nissan Pathfinder with a price of $2900 resignedly sitting in the corner of a used car lot right next to the abandoned lot. The thought crossed my mind: “Now if that were free, it might make a nice donor car for electric conversion.”

Why am I thinking such thoughts after I just got a NEV? Well, in part, it is because I am waiting still to get it licensed. It has been over a month since I purchased it and all I have done is drive around the immediate neighborhood, rather than to the grocery store, appointments, etc. (The purchase has presented me with another opportunity to practice letting go.)

You already have seen me make reference to electric conversion. In the previous post, I half-jokingly pointed to a wrecked Renault Clio and suggested that it might be a possible candidate for electric conversion. (The car had been run off into water and the engine compartment was submerged.)

So, other than it looked so forlorn and requires no shipping, why look at a SUV? Well, conversion of a utility vehicle is a popular high school or automotive training project because such vehicles have the extra capacity to accommodate more easily the greater payload that electric conversion requires. You give up the weight of the internal combustion engine in exchange for the greater weight of the energy storage system.

For instance, one recommended power source is a set of 24, 6-volt, T-105 traction batteries wired in series for a total of 144 volts. Each battery weighs 113 lb (51.4 kg) and measures 10-3/8” (264 cm) L X 7-1/8” (181 cm) W X 11-3/16” (284 cm) H. Do the math and you can see why hobbyists favor those vehicles, which offer the extra capacity to hold the batteries in battery boxes and carry so much additional weight. One also needs deep pockets; 24 long-lasting, deep cycle batteries are a significant portion of the total expense of the conversion, even when you purchase standard, “flooded” lead acid batteries, e.g., Trojan T105 or U.S. Battery 2400.

Note: A 6-volt battery in the T-105 group will provide 180 to 220 aH. (Amp-hours at a discharge rate of 20 amps per hour is a frequently reported measure of capacity.) Another means of comparison is the minutes you can expect the battery to discharge 75 volts. The more minutes that the battery can discharge 75 volts, the greater is its capacity, which translates to more work (force over distance) that electric drive propulsion system can do.

Some Electric Conversion Resources

  • Electric Vehicles of America is a good technical resource for electric conversion
  • The heart of an electric vehicle, so before you get started you may want to get a degree from Battery University or, at least, peruse the extensive information.
  • Simon Richardson started an Electric Car project and stopped due to shortage in funding
  • The Electric Vehicle Album is an example of “seeing is believing”
  • Electroauto.com offers a kit
  • metricmind is a place to shop if you are interested in high-end, AC drive systems and power electronics for electric vehicles
  • If you like to shop for discount parts, then take a look at EV Parts (Rod’s Garage)
  • evsource.com is another source for electrical components, e.g., Manzanita, Zilla, etc.
  • The George W. Bush Officious Forum has an interesting discussion about “Converting Your Car to Electric”
  • The Electric Vehicles Association of Greater Washington, D.C. provides an online resource: “Build an EV”. (Pictured above is not a GEM or even a Nissan, rather it is 1986 Ford Escort. Its conversion to a BEV is what is used as the example in the online document.)
  • The Mid-America Electric Auto Association has a FAQ, “So You Want to Build an Electric Car?”, plus a useful set of links
  • Shari Prange covers an important subject with electric car conversion: what to save and what to scrap.
  • Cameron Motor Works tells about a New Beetle Electric Vehicle
  • Kinetek Products is a corporation with several companies producing electric vehicle products
  • Fest-EV-a is a weblog of Stefano Landi who is converting a 1991 Ford Festiva L on a shoestring budget ($4500 CDN) with a garage full of household grade tools.
  • Peak Oil News and Message Boards has advice on building an electric car for those interested
  • Tell the Battery Layout Tool how many battery boxes you want, how many batteries to put in each box, what size and type of battery you’ll be using. The tool then creates an interactive page to let you experiment with the layouts. You can resize the boxes, drag the batteries and boxes around the page, and when everything is just right print out (or screen capture) the page.
  • Jerry Halstead (”Helping People Get Rid of Gas Since 1995″) has a weblog with alternate transportation news and links, plus regular updates as author converts a Ford Probe to an electric car.
  • EValbum's “So You Want to Build an EV?“

I recognize one reason why my mind is on electric conversion; I am second-guessing my choice, i.e., telling myself that a better choice might have been a previously owned electric conversion, one with doors that my spouse could use as a backup commuter vehicle. Nevertheless, such a project is somewhat intriguing.

I recently replied to someone who asked the evlist for help because he wanted to convert an AUSTIN MINI on a limited budget. I offered what I now know is standard advice to the novitiate; start with the power source and plan your retrofitting around it.

Another sound bit of advice was to consider how to transfer the power to the wheels. It was sound advice because that choice will dictate other choices, i.e., the choice of drive shaft effects the choice of motor, which effects the choice of controller that determines what sort of regenerative braking the vehicle can have.

With a low speed vehicle one can simplify by eliminating a transmission; the electric motor is directly coupled to the drive shaft. Besides lessening design requirements, elimination of the transmission reduces weight and maintenance. On the other hand, a lack of mechanical gearing is a disadvantage when hill climbing and is discouraged if one wants an electric vehicle that can reach highway speeds efficiently.

BTW: An extensive source of links regarding electric vehicles is electrischvoertuig.

Continue reading here: Fight Frumpy, Seattle, Go eBike on Lithium

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