Electric vehicle conversion
In automobile engineering, electric vehicle conversion is the replacement of a car's combustion engine and connected components with an electric motor and batteries, to create an all-electric vehicle. Another option is to replace a large combustion engine with an electric motor (for power) and a small combustion engine (for speed), creating a hybrid electric vehicle or a plug-in hybrid electric vehicle.
The general trend appears to be that ground vehicles will "go electric," and automakers have slowly but steadily responded to public demand by producing both hybrid electric vehicles which get 5.2–2.6 l/100 km; 45–90 mpg‑US gasoline, and electric vehicles which get similar or better mileage by mpg equivalent efficiency rating.
In general, commercially-manufactured electric vehicles are inhibited by the limited range per charge of batteries (up to 560 km, 350 miles), battery charge times that are slower than gasoline filling times, apparent greater initial cost over combustion engines, and potentially high service costs for used or worn-out batteries. Electric conversions are often inhibited by either the difficult labor and specialized knowledge involved in a do-it-yourself (DIY) conversion, or the expense of a purchased conversion service with conversion components, often costing US$8-12 thousand. There is a small but steadily growing DIY community for electric conversions.
- 1 Simple steps
- 2 Elements of a conversion
- 3 Hobbyists and conversions
- 4 Solar power
- 5 Conversion process
- 6 Industry
- 7 Vehicle types
- 7.1 Electric bicycle
- 7.2 Economy coupe
- 7.3 Compact sedan or coupe
- 7.4 Full-size sedan
- 7.5 Sports car
- 7.6 Light truck
- 7.7 Other trucks – full size and most SUVs
- 7.8 Classic Cars
- 7.9 Electric buses
- 7.10 Racers
- 7.11 Custom chassis
- 7.12 Novelty vehicle
- 8 Registration of converted and newly constructed vehicles
- 9 See also
- 10 References
- 11 External links
Assumes a simple design of a DC or AC motor.
- Obtain an electric motor, electric vehicle (EV) motor controller, and batteries which match the car size and the performance characteristics (range, speed, power) desired. Smaller vehicles can use smaller ("8 inch") motors, and larger vehicles will require larger electric motors.
- Remove the combustion engine, fuel tank, muffler and exhaust, and other ICE related components.
- Keep the transmission, and design an adapter out of an aluminum plate material, or steel tubing, which will accept the electric motor and mount it to the transmission at the precise distance. Adapter plate machining (and other machining jobs) can be outsourced to a machinist.
- Design a coupler for connecting the motor shaft to the transmission.
- Mount the motor to the transmission, with coupler and adapter firmly mounted.
- Build compartments to house the batteries. Cutting out part of the auto body is possible, and steel tubing should be used to frame the compartment.
- Install the batteries and the motor controller, linking them up to the motor.
Elements of a conversion
- Almost any vehicle can be converted to electric. Many people prefer to pick a vehicle that is light and aerodynamic in order to maximize distance traveled per battery charge. There must also be adequate room and load capacity for batteries.
- If obtaining a vehicle for conversion, chose a car which has an undamaged body (unless also doing the body work).
- The battery pack, which provides a source of electrical power. The most commonly available and affordable batteries are lead-acid flooded type. Next are the AGM (Absorption Glass Mat) sealed maintenance free batteries, a little more powerful and expensive. Then there are the more exotic batteries like Ni-MH and Li-ion; more difficult to find but light and longer lasting, maintenance free, and much more expensive. The new lithium batteries are showing some promise for EVs in the near future.
- 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 electric motor(s), controlled by an electronic throttle.
- 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
Hobbyists and conversions
Hobbyists often build their own EVs by converting existing production cars to run solely on electricity. There is a cottage industry supporting the conversion and construction of BEVs by hobbyists. Universities such as the University of California, Irvine even build their own custom electric or hybrid-electric cars from scratch.
Short-range battery electric vehicles can offer the hobbyist comfort, utility, and quickness, sacrificing only range. Short-range EVs may be built using high-performance lead–acid batteries, using about half the mass needed for a 100–130 km (60–80 miles) range. The result is a vehicle with about a 50 km (30 miles) range, which, when designed with appropriate weight distribution (40/60 front to rear), does not require power steering, offers exceptional acceleration in the lower end of its operating range, and is freeway capable and legal. But their EVs are expensive due to the higher cost for these higher-performance batteries. By including a manual transmission, short-range EVs can obtain both better performance and greater efficiency than the single-speed EVs developed by major manufacturers. Unlike the converted golf carts used for neighborhood electric vehicles, short-range EVs may be operated on typical suburban throughways (where 60–80 km/h, 35–50 mph speed limits are typical) and can keep up with traffic typical on such roads and the short "slow-lane" on-and-off segments of freeways common in suburban areas.
Faced with chronic fuel shortage on the Gaza Strip, Palestinian electrical engineer Waseem Othman al-Khozendar invented in 2008 a way to convert his car to run on 32 electric batteries. According to al-Khozendar, the batteries can be charged with US$2 worth of electricity to drive from 180–240 km (110–150 mi). After a 7-hour charge, the car should also be able to run up to a speed of 100 km/h (60 mph).
In 2008, several Chinese manufacturers began marketing lithium iron phosphate (LiFePO
4) batteries directly to hobbyists and vehicle conversion shops. These batteries offered much better power-to-weight ratios allowing vehicle conversions to typically achieve 120–240 km (75–150 mi) per charge. Prices gradually declined to approximately US$350 per kW·h by mid-2009. As the LiFePO
4 cells feature life ratings of 3,000 cycles, compared to typical lead acid battery ratings of 300 cycles, the life expectancy of LiFePO
4 cells is around 10 years. LiFePO
4 cells require more expensive battery management and charging systems than lead acid batteries.
On-board solar cells can be used to power an electric vehicle. The small power generated by solar cells mounted on a vehicle means that the other components in the system must be special to compensate for this. For example, the body of even a small conventional car converted to electric is still too heavy to be driven by on-board solar cells. A practical solar-powered vehicle is designed from the ground up with specially made parts.
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. In some cases, the vehicle itself may be built by the converter, or assembled from a kit car.
A two-stage vehicle is a vehicle that has been built by two separate manufacturers. The result is a standard, complete vehicle. In this process, vehicles may be converted by a manufacturer (as was done by Ford Motor Company to create the Ford Ranger EV). Alternatively, in a process known as "third-party (power)trainization", an independent converter will purchase new vehicle gliders (vehicles without a motor or related equipment) and then perform the conversion, to offer a two-stage vehicle.
In some countries, the user can choose to buy a converted vehicle of any model in the automaker dealerships only paying the cost of the batteries and motor, with no installation costs (it is called pre-conversion or previous conversion).
An electric bicycle is a conventional bicycle that has been fitted with an electric motor. Converting an existing bicycle by retrofitting it with a "conversion kit" is the simplest and least expensive electric vehicle conversion option. Most often electric bicycles or "e-bikes" 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 supercapacitors 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 a small amount of energy from braking and can re-charge the batteries while braking or traveling down hills (regenerative braking).
Some electric bikes have features where the motor can move the bicycle by itself (immediate start) if the rider chooses not to pedal with a button or throttle controller, while others require the rider to pedal at all times (pedal assist). 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).
Many battery technologies are available for powering electric bikes. The most common and least expensive battery technology is sealed lead acid but LiFePO4 is fast becoming the battery of choice for the e-bike.
Converting one's bike to electric with a conversion kit is an easy and affordable solution for most people interested in learning more about electric vehicle conversion.
There may be some problems with the warranty however on the original bicycle being converted, if an electric bike conversion kit is added. Low-speed scooters are not typically suitable for on-the-road use. These may be configured for either standing or sitting use. Some local laws apply bicycle laws to scooters, such as helmet and pedestrian right-of-way considerations.
Owing to its light weight and efficiency, a light vehicle can make an excellent choice, particularly if care is taken in component selection and placement. 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 Golf.
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 increase range in many practical driving conditions. In the same way that a gasoline-powered economy car is cheaper and more efficient to run, an electric-powered economy car is as well.
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. 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. Another example is a 1987 Mitsubishi Tredia where the rear batteries have been raised above the trunk floorspace, sealed, and externally vented. With suspension modifications, increasing shock length & spring rating, the car must still be below GVWR, even with the driver and passengers. Exceeding the total design weight of the vehicle would be illegal in some states, and might result in cancellation by an insurance company.
There is an effort by several engineers in California to make the Toyota Prius a "Plug-In Hybrid Electric Vehicle," or PHEV, whereby the first 40 miles are driven by all-electric power, then the gasoline engine comes on to re-charge the batteries, only if the commute is further than 40 mi. If it is less, one can just plug it into the utility grid to re-charge the batteries. The process is done by removing the nickel-metal hydride batteries, and installing different batteries, and a different battery management system.
Full-size sedans and minivans are generally considered to be poor candidates for EV conversion. As the suspension and tires are already operating close to the maximum permissible[clarification needed], 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.
One of the possibilities is using the body of Audi's D2 platform A8 (1994–2003) Audi A8 or sports sedan S8 (1998–2003 or older European market models where the German model weights 1730 kg) Audi S8 both of which are all aluminium monocoque "Audi Space Frame" vehicle, which helped to significantly reduce weight without being any less rigid.
For a person interested in sports car performance and appearance, the creation of 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. These vehicles can offer stunning performance in the lower speed ranges owing to light weight and rear wheel drive, and may also offer good range due to their superior aerodynamics.
The 1969–1976 Porsche 914 is one of the more successful sports car conversions, as well as being one of the most popular. Once converted, it boasts better performance in range, acceleration and top speed than most other vehicles. Also, its low acquisition costs contributes to its popularity as a conversion candidate. Some manufacturers of conversion kits have made a kit specific to the 914.
Another popular sports car used for conversion is the 1984–1989 Toyota MR2. Reasons for its popularity are low weight before conversion, low cost to purchase the car, and available locations within the car to place the large batteries that most people use (lead-acid and its derivative technologies). The later MR2 body style (Mark 2) does not seem as popular, and as of March 2008, there is only one known conversion.
A 1983 Mitsubishi Starion was converted to all-electric in 2009 by Carmel Morris and Nathan Bolton in Australia. This sports vehicle had divided front/rear battery load for well-balanced low center of gravity performance. The battery pack consisted of 45 x 3.2v nominal lithium-ion batteries. The tar weight of the final result was not much greater than the original specification, allowing the sports car to be engineering road-certified as a four-seat vehicle. The builders wanted to prove that an electric car conversion could also include other options such as power steering and air conditioning (as is the norm for new electric vehicles), without sacrificing excess energy or comfort. Information on the successful Electric Starion conversion can be found on the web.
The Bradley GT II as well as other VW-based kit cars are very popular conversion candidates due to their being inexpensive, extensive support groups as well as their simple sports car design. Availability of conversion kits for these cars are quite prevalent with commercial retail establishments that specialize in EV conversions.
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 or below the cargo bed, much or all of the spatial utility remains. A light truck is highly recommended as a first conversion effort because of the simplicity of component layout. With proper battery placement the stability of a late production truck can be improved over the ICE version. While a number of suitable vehicles are available in pre-2002 models, the modern evolution of this type has become taller, heavier, bulkier and less efficient, and their excessive height makes under-bed battery placement essential to keep the center of gravity low enough for stability on curves.
Other trucks – full size and most SUVs
These are rarely converted due to their excessive weight, and aerodynamic inefficiencies. To make the situation worse, many modern trucks and SUVs continue to get bulkier, heavier, and their high stance means the height of the center of gravity leads to instability while making high speed turns, a distinct disadvantage if there is not enough room between the frame rails to enable low battery mounting. 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. (Such considerations are important due to price, weight, and performance limitations of current battery technologies.) 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 Land Rover EV converted by Wilde Evolutions, and the 1988 Jeep Cherokee EV converted by Nick Viera.
Although technologically feasible, classic cars are not widely converted in order to maintain a car's authenticity. The German company ReeVOLT has however made it one of their business branches to convert old Trabants for use in tourism in the east of Germany in connection to the car's regional historic significance and to allow easy access to environmental zones such as city centers and in particular the partially car-free island of Rügen. The car is considered ideal for conversions because of its low used price and low weight due to the small size and resin fiber construction.
The most economically effective development in this area involves the creation of hybrid electric buses (mainly plug-in hybrids), well suited to this application owing to frequent stops and starts and effective energy recovery and release in this cycle.
Transdev York in the United Kingdom currently operate the world's first diesel-engined buses that have been converted to full-electric propulsion. A fleet of five late 1990s Dennis Trident 2 open-top double-decker buses, operated for a local City Sightseeing contract, have been converted from diesel to electric power.
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" 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.
EV's have proven successful in autocross competition. The electric motor's ability to deliver maximum torque at 0 RPM and a comparatively broad torque band provide good throttle response and allow running an autocross without any time lost to shifting gears. The short distance of the typical autocross requires less stored energy than most forms of motorsports. This minimizes electric vehicle's most obvious competitive disadvantage, the weight penalty of batteries compared to gasoline.
Intended only for specialized straight line quarter-mile (acceleration) racing this type of vehicle is used only "off road" at specialized "dragstrips".
High speed straight line racer
- For an example of a straight line racer see Buckeye Bullet
Even more specialized than the drag racer, this is intended to obtain high speeds on long, straight, and flat raceways, such as the dry lake beds found in locations such as the Bonneville Salt Flats.
Closed circuit road racer
Closed Circuit Road racing, particularly any type of endurance racing, is one of the greatest challenges for EV's. Pound per pound, gasoline contains far more energy than even the most advanced of current batteries. An electric vehicle must be heavier or more efficient to run the same distance as its gasoline competitor. Endurance racing strategies include battery packs that can be changed quickly and "Dump charging"
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. Many VW-based kit car companies have tube chassis ready to start with.
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. This vehicle is ideal for the beach (where not prohibited) and to promote tourist places but will usually require trailering to its operating site.
Registration of converted and newly constructed vehicles
The ease of registration will vary by state. Some states require safety inspections, usually to ensure body integrity in areas subject to severe corrosion from winter road de-icing materials. In any case, for general registration all functional safety equipment should be operating – turn signals, brake lights, headlights, horn, etc. The windshield should have no running cracks (small stone chips and "stars" may be acceptable if not in the driver's principal line of vision). If the vehicle has been reconstructed from a salvage vehicle (a vehicle whose registration has been forfeited) inspection may be more severe to ensure compliance and the legitimacy of sources of salvage components by presentation of proper purchase receipts.
Registration procedures will vary by state and will usually be more difficult (even bizarre) in states with strict emissions requirements (even though a plug-in only conversion will be a zero emission vehicle). Arguing with DMV staff is typically futile in all jurisdictions, but there may be appeal procedures available but whose availability may not be openly publicized.
On the other hand, changing the registration allows a conversion to qualify for tax incentives available in some states, such as Oregon, for either the vehicle, the charging system, or both.
California (US) conversion registration and taxation
Registration of a converted existing, or newly self-constructed electric vehicle in California is no longer difficult.
This falls into two categories; First, if the vehicle is built from new frame components and possibly some salvage parts, (i.e., it has never been a previously titled motorcar previously, but it has brakes or axles that were obtained used/rebuilt.) In California if you "create" a car from scratch and want to register and title it with DMV, you need to go through the "Specially Constructed Vehicle Emission Control Program" or SPCNS for short, this is also called California "SB100" program. Or Second, a previously registered vehicle converted to electric propulsion.
SPCNC: In the past, the process of registering an SPCNS vehicle required meeting with an outside referee at a community college or one of the states mobile referee stations to verify the vehicle. The current process happens at the DMV with the inspection being done by A DMV inspector. The inspector will need to be able to see the motor and batteries and verify that there in no internal combustion engine. The vehicle will still need a brake and light inspection By an outside inspector to verify its compliance with other vehicle codes.
Currently Registered Vehicles: If you are converting an existing vehicle and it is older than 1975, you may opt to not bother to get the vehicle converted to the "E" code unless you are looking for the Diamond Lane stickers, since these vehicles don't require a smog inspection. For vehicles newer than 1975 you will need to go the DMV and have the vehicle inspected as a conversion. The batteries and motor will have to be exposed so the inspector can see them and verify that there is no internal combustion engine.
The next step requires the clerk at the local California Department of Motor Vehicles (DMV) office to call the Sacramento office. Only the Sacramento office can make this entry into the computer system. If the local clerk tries, the system will default to the "Q" code for hybrid. (These procedures are in place to inhibit fraudulent registration of ICE vehicles as Electric in order to avoid smog inspections.) A hybrid is not exempt from smog inspection. Before you leave the DMV make sure your printout has the proper "E" code or you will have to go back to do it again.
There is weight fee of $87 for vehicles under 2,700 kg (6,000 lb) or $266 for vehicles from 2,700 to 4,500 kg (6,000 to 10,000 lb). This is in addition to any regular registration fees.
- Aftermarket (automotive)
- Electric car
- Engine swap
- Green tuning
- Kit car
- Maker culture
- Plug-in hybrid (PHEV)
- Vehicle glider
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