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Electric vehicle conversion

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An electric vehicle conversion is the modification of a conventional internal combustion engine (ICE) driven vehicle to battery electric propulsion, creating a battery electric vehicle. In some cases the vehicle may be built by the converter, or assembled from a kit car, and vehicles of this type are also noted below.

Vehicles may be converted by a manufacturer (as was done by Ford Motor Company to create the Ford Ranger EV or by an independent converter that purchases new vehicles without motors and related equipment (these are called "gliders"). Most conversions in North America are performed by hobbyists who typically will convert a well used vehicle with a non-functioning engine, since such defective vehicles can be quite inexpensive to purchase. Other hobbyists with larger budgets may prefer to convert a later model vehicle, or a vehicle of a particular type.

Elements of a conversion

  • The battery pack, which provides a source of electrical power.
  • The charger which restores energy to the batteries (which may be mounted within the vehicle or at a special charging station at some fixed location)
  • The power controller, which regulates the flow of energy between the battery and the motor(s)
  • One or more electric motors and their mechanical attachment to the driveline
  • Power conductors connecting the battery, controller, and motor(s)
  • Accessory equipment to power auxiliary equipment such as power brakes and heating system
  • Control circuitry and equipment to allow control and interlocking of the various components
  • Instrumentation specific to the operation and maintenance of the conversion

Vehicle types (including scratch built)

Economy coupe

Owing to a lack of load carrying capacity, a light vehicle can make a poor choice unless substantial care is taken in component selection and placement and use restrictions are accepted. It is possible to obtain conversion kits for some popular light vehicles, most notably the rear motor, rear drive Volkswagen Beetle, its Type 3 evolution, and its successor, the front motor/drive VW Rabbit. One should not expect to convert such a vehicle and then use it to transport four full size (or oversize) adults - the cars simply do not have the safe load carrying capacity both the normal maximum live load and the heavy battery pack. Instead, count on simply removing the rear seat to obtain space for light luggage. Rear wheel drive vehicles are especially suitable for high performance applications as the weight transfer due to acceleration will increase the traction on the driven wheels.

By converting a light vehicle it is possible to use a smaller motor, which both weighs and costs less than a larger motor. A lighter overall vehicle weight will reduce power consumption in start and stop traffic and so increase range in many practical driving conditions.

(At least one commercial converter, Solectria, has converted the front wheel drive General Motors Geo Metro for electric use, creating the Solectria Force.)

Canadian Electric Vehicles have conversion kits for an electric Geo and a whole range of vehicles from compacts to trucks.

Compact sedan or coupe

A compact sedan may be a better choice than a subcompact owing to better load capacity and more room for battery placement. Some commercial EV Conversions use vehicles in this size range. One example is a 1992 Honda Civic [1]. In this conversion, the back seat was retained, and there is still enough room to sink nine flooded lead acid batteries low in the trunk where the spare tire was located, as well as another nine batteries under the hood. With suspension modifications, (increasing shock length & spring rating), the car will be at GVWR as the driver gets in the car, but since most vehicles are engineered with a little "wiggle room" in their ratings, the vehicle is still quite safe.

Full size sedan

Full size sedans and minivans are generally considered to be poor candidates for EV conversion. As the suspensions and tires are already operating close to the maximum permissible it may be necessary to make substantial modifications in these areas. It may be easier to obtain upgraded suspension components for some smaller vehicles, if these are also typically used for sports racing (particularly autocross). Starting with a heavy vehicle and adding batteries will result in poor performance in acceleration, handling, braking, and economy of operation.

Electric motorcycle

A specialty niche, this can offer an opportunity to build a relatively low cost electric vehicle. Most of these use a two wheel configuration, although the two types of three wheel vehicle (and sometimes four wheel vehicles) are classified as motorcycles in many jurisdictions if their weight is sufficiently low (typically around 1000 pounds maximum). If a tricycle layout is employed the single wheel should be at the back, with normal automotive type front wheel steering, as the single wheel forward type is notoriously unstable in handling.

Electric bicycle

An electric bicycle is a class of bicycles that are fitted with an electric motor. Often they are powered by rechargeable batteries however some experimental electric bicycles run directly on or recharge their batteries via solar panels, fuel cells, gas generators or other alternative energy sources. Some experimenters have even used super capacitors to store energy. Using an on-board generator may impact the legal jurisdictional definition of an electric bicycle. A few types of electric bicycles are able to re-capture energy from braking and can re-charge the batteries while braking or travelling down hills (regenerative braking). With the advent of newer technology further features can be expected.

Some electric bikes have features where the motor can move the bicycle by itself if the rider chooses not to pedal, while others require the rider to pedal at all times. This latter type may in some jurisdictions allow the vehicle to be used on bicycle trails that otherwise prohibit motorized vehicles of any kind. (See motorized bicycle).

The conversion of a bicycle to electric power is probably the lowest cost means of learning conversion methods. Battery packs are usually lead acid gel cells since these are available in small sizes suitable for this application. It is also practical to experiment with more expensive battery types since only a small pack is required. It is possible to repurpose battery packs and chargers intended for powering toys and similar small electrical devices.


Electric Scooter

Not typically suitable for on the road use these may be configured for either standing or sitting use

Sports car

For a person interested in sports car performance and appearance a satisfying conversion will likely lead to a number of difficulties in such details as battery disposition, as such vehicles generally have available space distributed in small volumes around the vehicle. This leads to complexity in securing and wiring batteries. Such vehicles can offer stunning performance in the lower speed ranges owing to light weight and rear wheel drive and may also offer good range from their superior aerodynamics.

Tesla Motors has produced a spectacular high end electric sports car.

Light truck

Light trucks are especially suitable for hobbyist conversion because it is easy to locate batteries remote from the passenger compartment and there is a good load handling capacity for the use of heavy batteries such as the flooded lead-acid batteries commonly used in golf carts. Light trucks also offer substantial utility in use simply because they are trucks. Even if a portion of the weight capacity is removed by the presence of batteries within the cargo bed, much of the spacial utility remains. A light truck is highly recommended as a first conversion effort because of the simplicity of component layout.

Canadian Electric Vehicles produce conversions for many types of vehicles - including light trucks.

Hotrod

While this type of vehicle is usually made to be a "street legal" performance machine it may also be developed for occasional use as a drag racing vehicle. The leading vehicle in this field is the "Maniac Mazda" [2] a Mazda RX-7 sports car converted from rotary engine to electric by Roderick Wilde. This vehicle can outrun Dodge Viper and Ferrari sports cars in quarter mile drag races.

Autocross racer

EVs may prove to be especially suitable for autocross contests as low speed acceleration is especially important to success in this type of racing. Specific classes for electric autocross (called electrocross ) are being introduced in some venues. Vehicles for these will typically be economy car conversions or custom built chassis but with excess rear weight bias to allow agile handling under the control of an experienced driver (such rearward balance may be dangerous for everyday use).

Drag racer

Intended only for specialized straight line quarter mile (acceleration) racing this type of vehicle is used only "off road" at specialized "drag strips".

High speed straight line racer

Even more specialized than the drag racer this is intended to obtain high speeds on long, straight, and flat raceways, such as the dry lakebeds found in locations such as the Bonneville Salt Flats.

Custom chassis

Suitable for a builder who is capable of constructing a kit car, with good abilities and equipment in machining and welding this can result in a unique vehicle. It is especially suitable for the construction of a lightweight vehicle that can offer exceptional performance.

Other trucks - full size and most SUVs

These are rarely converted due to their excessive weight, instability, and aerodynamic inefficiencies. To make the situation worse, many modern trucks/SUVs continue to get bulkier and heavier while their frames (or unibodies) are built thinner and lighter. As a direct result, the payload carrying capacity and thus the GVWR of the vehicles goes down. Such a trait is not desirable because it limits the weight of the battery pack that can be carried, limiting the maximum battery-to-vehicle weight ratio that could be achieved for the vehicle when converted to an EV. For a given battery type, reducing the battery-to-vehicle weight ratio always results in reduced vehicle range per charge. However, despite these mostly unavoidable limitations, several SUVs and larger trucks have been successfully converted to electric power by hobbyists. Some examples include the "Gone Postal" van converted to an EV racer by Roderick Wilde and Suckamps EV Racing, the 1971 Land Rover EV converted by Wilde Evolutions, and the 1988 Jeep Cherokee EV converted by Nick Viera.

[3] 2005 Dodge Ram converted by David Taylor, Re-Involt.

Novelty vehicle

At the 2005 Stanford University EV Gathering

Above: Bob Schneeveis[4][5][6] demonstrates his Silver Sofa to the delight of his passengers. This can spin rapidly in place like a carnival ride and its batteries are recharged by the solar panels.

A novelty vehicle or an electric powered art car may not be suitable for on road use. Applications include electric vehicle show demonstrations, parades, parade floats, float towing, and eclectic off-road gatherings such as Burning Man.

External links

Wikibook available