Above: The Doran
©1994 Michael Hackleman
The 1998 mandate for ZEVs (zero-emission vehicles) is still a long way off for many folks who are ready right now to roll down the highways in cleaner transportation.
Beginning in 1998, it's expected that 40,000 electric vehicles per year will be registered in California alone. Even if someone is patient enough to wait, the selection available to consumers may be poor. Major auto makers will steer clear of affordable commuting vehicles lest they compete with internal combustion engine vehicles. Fleets are the most likely recipients for vehicles that would fall into this category. Fortunately, there are alternatives in two general categories: conversion and purpose-built EVs.
The conversion of a standard automobile to electric propulsion is the most common way to obtain an EV today. Converted vehicles are available from or performed by a number of companies like Solectria, Solar Car Corporation, ElectroAutomotive, Burkhardt Turbines, KTA Services, MendoMotive, Electric Vehicles of America and others. Kits and components are also available for the DIY (Do It Yourself) crowd. Conversion manuals make it easier to understand what's involved. Do your own skills stop at the business end of a screwdriver? If so, manuals will also help you to select qualified people when you need assistance.
Purpose-built EVs generally fall into one of three areas: production vehicle, kit car, or POC (proof of concept) vehicle. A production EV is one that has rolled off an assembly line somewhere. Kit cars are prototypes that may be duplicated by anyone who purchases a set of plans from the designer/owner. POCs are vehicles that reveal good design features that anyone may integrate into their own prototype.
Don't undertake an EV project until you have read a lot. You can easily spend $75 or more on EV-related material. It will save you ten times that much. If that amount of cash sounds impossible, the same word applies to the probable success of your project!
Two examples of production prototypes are the City-El and the Kewet, both imports. The City-El is a good example of a neighborhood EV. It's a nimble three-wheeler that's been around in Europe long enough to have evolved to its current standard. Though limited in speed, it's an all-weather vehicle that's well engineered and easy to drive, operate, and maintain. While there's space for a child (rear-facing), this is primarily a one-person machine. Apparently, liability issues have halted its commercial availability in the USA. Even so, a number of them exist in the Sacramento area. The Kewet is a solid four-wheel machine that seats two and is completely at home on the street. Its no-nonsense look and high visibility to other drivers will give its driver a warm-tummy feeling. (The Kewet's two-year airbag exemption period expired in the USA. An extension has been filed. You may still be able to get one from Green Motor Works, Hollywood, CA).
The Doran and Vortex are examples of EV kit cars. Both are three-wheeled, two-seat prototypes designed to be built from plans. Since both vehicles were originally built around engines, they evolved significantly in design through use.
The Doran was designed and built by Rick Doran. Three wheels were chosen to minimize weight, decrease rolling resistance, and ease licensing. The Doran's front-wheel drivetrain is built around a 1980-89 Subaru Hatchback transmission and transaxle assembly. Two steered wheels up front makes an aerodynamically clean, teardrop-shaped body possible. A common fear held by the general public is that a 3-wheeler is more susceptible to a rollover than a 4-wheeler. Nonsense! A properly designed 3-wheeler can have an overturn resistance as good as or better than most modern sedans. In tight turns, the tires will lose adhesion long before enough side force can be developed to flip the vehicle. The specific physics of 3-wheelers, along with construction plans and diagrams (including fiberglassing notes) are thoroughly discussed in Rick's 94-page book. My copy is getting worn from use.
The Vortex is a three-wheeled sports vehicle designed by Steve Pombo. It's intended to be home-built from plans. The builder need only possess average tools and craftsman skills. In this design, the rear wheel assembly is powered. The rear swing-arm, axle and tire are built into a cradle for easy removal. The Vortex body is hand-shaped and built of urethane foam and fiberglass. The chassis uses a plywood monocoque structure. The front suspension is a sophisticated double A-arm unit from the Triumph Spitfire. It includes the Spitfire's rack and pinion steering, anti-roll bar, and oversized disk brakes. The vehicle is built directly from engineering plans (CAD-drawn plan sheets) and a 64-page booklet.
POC vehicles point the way toward a successful, scratchbuilt EV. Scratchbuilt vehicles have a very important attribute. It may be the only way to get exactly what you want. But there's a price to pay. Contrary to popular opinion, a scratchbuilt EV is not the fastest, easiest, or least expensive way to own an EV. It will take a long time to do. It will probably cost as much as a conversion. It also demands an honest evaluation of your competence and ability. One thousand pounds of human and machine hurtling along at any speed is horribly unforgiving of design or construction error. The wise scratchbuilder does not reinvent the wheel. Instead, this person mixes existing subassemblies from other vehicles. They combine the right proportion of weight, aerodynamics, rolling resistance, hill-climbing ability, efficiency, ergonometry, and crashworthiness. Each machine must unite frame, brakes, suspension, steering, and body-shell with the propulsion package. It's a big, big job. Think legal. An EV that will use the roads must be certified, registered, and licensed. Purchase a copy of the current Vehicle Code for your state. Look it over for anything that might apply to an EV. Don't get snagged on a technicality!
For the virtues they hold, and the direction they may give in "rolling your own", I've included six photos of POC vehicles. They include a kitcar Porsche, the Windmobile, the Sylph, the Formula E Autobat, an HPV Vector, and an Aerocoupe.
• John Sprinkle put a replica fiberglass Porsche body on a VW chassis to ease the overall process of building an EV. He quickly abandoned an early hybrid arrangement and enjoys cruising and commuting in his pure-electric machine.
• Jim Amick's Windmobile combines good crashworthiness and a dual-drive system (twin motors at each of the rear wheels) with lots of aerodynamic detail. It helps to live in a very windy area or enjoy lots of attention.
• The Sylph was designed by Matt van Leeuwen at a time when good EV components were unavailable. Despite the use of a Goldwing engine, this prototype represents the kind of packaging that would complement today's EV technology. It keeps a high-profile for street use, arranges the driver and passengers in spacious 3-seats, offset tandem style, and maintains cleans lines, despite its payload.
• The Formula E racer was built by Ely Schless and raced at Phoenix by the Hackleman-Schless team. It swept the 1st place trophies in its class in both events in 1992 and 1993. Its exchangeable saddlepack battery modules, combined with a single-ratio drive, a 10 HP propulsion motor, and a curb weight of only 1,200 pounds represents an exciting template for designers of 4-wheel street machines. Positioning a driver and passenger above the battery pack for better visibility would make this a strong, unlimited range vehicle.
• The Vector and Aerocoupe are lightweight, 3-wheel body-shells designed for HPV (human-powered vehicle) use. The Aerocoupe is used extensively with electric-assist or electric-only operation in the Electrathon racing circuit. Their value to the prospective EV builder is their commercial availability. This bypasses the need to use fiberglass for the body and windshield. Purchasing either one (or similar body-shells) can shave a big chunk of time and nastiness off an EV project.
Author: Michael Hackleman, POB 63, Ben Lomond, CA 95005 • email to [email protected]. This article, includes condensed material excerpted from The New Electric Cars: Simple, Efficient and Reliable, by permission of Chelsea Green Publishing. Available in May 1995. • Doran Book ($39.95) available from: Rick Doran, 6290 Sunrise Meadows Loop, Reno, NV 89509
Vortex Design Plans ($40.00) available from: Dolphin Vehicles, PO Box 110215, Campbell, CA 95011
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Electric Vehicle Suspension
©1994 Shari Prange
One important aspect of an EV that is too often ignored is the suspension. Atypical conversion has over a thousand pounds of batteries. This means the car overall is 800 pounds (or so) heavier than its original weight.
It's easy to spot the EVs with bad suspension; they're low-riders. Many are tail-heavy and nose-high. A few are nose-heavy. Some just squat on all four wheels. If you look at them from the end, you may see wheels splayed outward.
Poor suspension can cause other problems besides making you look silly. It will not be possible to get a proper alignment on the wheels. The most serious result of this is poor handling, especially in an emergency situation. If you have to make a quick maneuver, the car may not steer properly.
If the wheels are splayed out (a condition called "excess negative camber") the tires won't be able to grab the road properly. They'll wear prematurely and unevenly, mostly on the inside edge where you might not notice.
Also, if the car's springs and shocks are continually compressed, they won't be able to do their job properly.
Now is the time that some of the numbers you recorded before the conversion will come in handy. If possible, drive the car to a public scale and weigh it three times: front axle, whole car and rear axle.
Even if you can't take it to a scale, drive it just enough to get it settled down on its springs. Then park it on a flat, level spot and measure the ride height at each wheel. This is the measurement from the ground to the top of the wheel arch, at the centerline of the wheel.
These numbers tell you how much weight you added to each axle and to the car overall. You'll also know how many inches of ride height you gained or lost.
Above: Ride height is measured through the center of the wheel, from the ground up to the wheel arch.
If a car is heavy on one end, the other will be too high. Raising the heavy end will bring the light end back into line. If this is your situation, consider first whether you can redesign the battery layout to re-distribute the weight evenly.
Your suspension may be coil springs, leaf springs, or torsion bars. There are options for beefing up all of these.
Some kinds of suspensions, such as torsion bars, can be adjusted. You may be able to adjust the suspension enough to restore your ride height.
The easiest way to identify replacement springs is through the dealership. Find out if there is another model of car with a heavier-duty spring that would bolt in. This could be a luxury version of your car with a larger engine, air conditioning, or a towing package. It might be a completely different model - one that is heavier but uses suspension parts with the same dimensions.
If you can identify these parts through the dealer, you may be able to locate them in a wrecking yard and save a lot of money.
Another solution is an aftermarket replacement spring. Some models of cars are more likely to be modified by their owners than others. Those models will have commerically available overload springs.
Be sure you are getting good quality springs. The extra cost is worth it. If you have coil springs, don't be seduced into purchasing "coil spring helpers". These
Above: Springs come in different sizes and end styles. Shown are (left to right): late Rabbit front, early Rabbit front, and Rabbit rear.
little devices are installed between the coils of the spring. They prevent the spring from compressing in the way it was designed.
If you have leaf springs, there may be a good "helper" kit available for your vehicle. These are actually extra leaves that you add to your springs to stiffen them.
If you have no luck with the dealer or parts houses, you may need to get custom springs built. These may cost as much as $150 per wheel. Look in the Yellow Pages (of the major city nearest you) under "Springs".
The spring maker will want a lot of information about your old springs: height fully extended, height fully compressed, number of coils, diameter of coils, diameter of spring material, spring rate, and end mounting style. The mounting style refers to the way the end of the spring attaches to the car. The spring itself may be a continuous tube all the way up, or it may tighten into a "pigtail" at the end. It may be mounted "outer diameter constrained" or "inner diameter constrained".
As you might guess, the easiest way to get most of this information to the spring maker is to send him one of the old springs. He will also want to know how much weight you've added to each wheel (axle weight divided by two) and how many inches of ride height you need to restore.
Your new springs will probably look exactly like the old ones. They may look rusty since this type of metal develops a harmless surface coat of oxide. The difference is in the spring compression rate. This is the amount of pressure needed to compress the spring.
Finally, for cars with coil springs or torsion bar suspension that do not enclose the shock absorber, air shocks are an option. These can be pumped up with air to carry the necessary weight. If these are carefully installed in the beginning, they will give years of satisfactory performance without leakage problems.
If you have trouble finding air shocks for your model car, go to your aftermarket parts house and ask to see their KYB catalog. KYB has shocks for a wide selection of cars and trucks. Their catalog makes cross-matching easy.
First, locate the drawing and description that matches the dimensions and mounting style of your car's original shocks. Note the KYB designation for this style. Then check the charts to see which other models use this same style. Pickup trucks are good bets.
While the parts house may not show any listing for an air shock for your car, they may have one for another model which uses an identical shock.
Struts and Shocks
While we're on the subject, let's talk about struts and shocks. If you aren't using air shocks, this is a good
Above: Air shocks are a good option on many cars such as this VW Bug.
Above: Helper leaf springs beefed up the suspension of this Datsun pickup truck.
time to replace your struts or shocks with heavy gas-filled versions.
The purpose of the shock is to provide some resistance to motion and dampen the oscillations of the springs when your car goes over a bump. Your EV has more weight bouncing on those springs so a stronger dampening force is needed.
Do NOT attempt to change MacPherson strut inserts yourself. The springs are held onto the strut assembly under great tension. If you release that tension without the proper tool to contain it, you will create an instant unguided missile. The cheap "strut compressors" that use a piece of ready-bolt and a couple of hooks do not work. As you try to tighten them down, they simply "walk" around the spring.
Instead, take your whole strut assembly (or whole car) to a shop that specializes in that model of car and let them replace the inserts for you. It'll be much cheaper than a trip to the emergency room.
Anti-sway bars are not essential but they are recommended if they're available for your car. When you take a curve, the heavy batteries will try to continue to move in a straight line. Anti-sway bars counteract that tendency and help the car stick to the road in the curves. A good source for anti-sway bars is any place that caters to stock car road racers.
After you've installed your new suspension, take the car to a good alignment shop and get a full wheel alignment. Improper alignment will increase the car's rolling resistance which will decrease its efficiency and range.
A proper suspension will make your EV more pleasant to drive. It will increase the car's range and make your tires last longer. And most important, it will make your car safer on the road. After you've put this much effort and expense into your conversion, take the time to give it a good suspension and finish the job properly. You won't regret it.
Author: Shari Prange, Electro-Automotive, PO Box 1113, Felton, CA 95018 • 408-429-1989
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Hybrid Cars! Man! Is that a HOT topic right now! There are some good reasons why hybrids are so hot. If you’ve pulled your present car or SUV or truck up next to a gas pumpand inserted the nozzle, you know exactly what I mean! I written this book to give you some basic information on some things<br />you may have been wondering about.