The Hybrid-Configured Electric Vehicle Michael A. Hackleman ©1989 Michael A. Hackleman The general public currently perceives electric vehicles as poor performers -- slow to accelerate, and limited in speed and range. This belief is based on limited, first-hand experience with "pure EVs" -- ones using only batteries and is, for the most part, accurate. I have rarely experienced an EV, scratch-built or a converted vehicle, that is not sluggish. This turns me off since I find it difficult to ride in, or drive a sluggish vehicle. Accordingly, I find it difficult to advocate the use of electric vehicles to the general public. EVs are idyllic for environmental reasons and will gain prominence for this reason alone. However, if the North American driving public is to be weaned away from transportation using oil-based technology without a lot of kicking and screaming, performance and range of vehicles are major issues to address. I know that most people -- for the money, time and effort they might invest -- would be disappointed in EV performance today. More appropriate attitudes are needed. Rethinking the role of the automobile is one piece of the puzzle. Mindlessly using it to go just anywhere is nuts. Alas, we're "techie" junkies. Our addiction is obvious in light of impending oil depletion, widespread pollution and congestion, and social degradation from automobile-related issues. When it IS called for, personal transportation is archaic, lagging far behind the available technology. Major car manufacturers are NOT, for the most part, helping to change this situation. R&D efforts toward innovative vehicles are underfunded and the results of such work is undervalued, often shelved. Electric vehicle ventures rarely focus on weight, aerodynamic enclosures, or power train losses. Instead, exotic (high-density) batteries and alternate fuels get top billing -- at prices well beyond affordable levels. Even the hybrid EV is hard-pressed to compete with the convenience and performance of IC-engined vehicles. One way this gap closes is when the driver assumes some responsibility for vehicle operation. Again, appropriate use of the automobile is the best first bite. Driving habits also make a difference. Lower driving speeds of EVs ensures the highest electro-chemical efficiency in the batteries. That spells greater range for the same amount of power. Gentle acceleration and negotiating uphill grades at a slower speed also helps. Battery depletion is postponed by a significant amount. The life span of the battery pack increases, too. Transportation consumes more than 70% of our annual energy budget (not the low 13% I erroneously reported in my first article). Careful attention to issues like weight, aerodynamics, and hybrid energy systems will help the evolution of earth-minded transportation. I can easily envision operating my own high-performance, hybrid commuter EV within 1-2 years time. It must be affordable, efficient, and environmentally-benign. I call it the MBG prototype. (MBG comes from Michael, Brett, and Glenn, my three sons.) This article will discuss factors related to the MBG's design. Topics include: definitions, number of wheels, 3 versus 4 wheel design, the hybrid configuration, batteries, the onboard charger unit, photovoltaic panels, regenerative braking, instruments and controls, aerodynamics and crashworthiness. Definitions Several terms need immediate definition: hybrid-configured, high performance, and unlimited range. Hybrid-configured means that the vehicle uses two or more energy sources. In fact, the MBG will utilize four energy sources: batteries, an onboard charger unit (engine-generator assembly), photovoltaic cells, and regenerative braking. High Performance, by my definition, is the ability to accelerate quickly, reach freeway speeds, and climb grades at a reasonable rate. Unlimited Range is the ability to "keep going" as long as you add fuel, much like you would experience in a standard car. The addition of an onboard charger unit (OCU) -- a small, gas-fueled engine driving a generator, makes this possible. Specific design choices in the MBG enhance this feature by ensuring that the vehicle can, indeed, operate on the OCU alone, even when the main battery pack is depleted. It also means you won't get stuck somewhere because of a dead battery pack. Number of Wheels Our generation is used to seeing cars with four wheels. The Morgan, a 3- wheeled British commuter, was quite popular many years back. Three- wheeled vehicles are inherently more stable. (Think about it: you'll never see a 3-leg table teeter!). In vehicles, this stability is lost when two of the wheels are closer together than about 60 percent of the distance to the third wheel. The biggest advantage of 3-wheeled vehicles is that they are considered "motorcycles" in most states; this substantially eases the job of CRLI (Certification, Registration, Licensing, and Insurance) for an operational vehicle. Wheel Configuration There are two basic configurations of the 3-wheeled vehicle: the motorbike and trike. The MOTORBIKE has twin-steered wheels up front and a single-drive wheel in the rear. The TRIKE has one steered-wheel in front, and two drive wheels in the rear. Other arrangements are possible, but these two are the safest. Of the two designs, a MOTORBIKE is usually the easiest to build for several reasons. First, you're halfway there if you start off with the rear portion of a motorcycle. This gives you suspension, a sprocketed drivetrain, a wheel and tire, and a framework to which you attach the front half of the vehicle. If you're lucky enough to find a shaft-driven rear end, chances are the transmission will be separate from the engine (like in the BMW's) and you have the option of using it and the clutch as part of your design. Since most damaged motorcycles are crunched in the front end (ugh!), there's lots of hardware out there, ready and waiting to be recycled. Be picky! You want the registration and license plate! With those in hand, CRLI is simple and straightforward. The TRIKE is so-called because it looks like a big tricycle (you know, the old-timey version of Hot Wheels). Think CRLI. Either use the front end of a motorcycle with papers and license plate or the rear end of something that is certified and licensed (i.e., a small imported car, a Harley- Davidson Trike rear end, a Honda ATV, etc.) and hope that this is acceptable to the DMV. Note: A scratch-built EV without "carry over" papers is, if a 3-wheeler, normally registered as a motorcycle or "experimental". Meeting all vehicle codes is essential. Of all aspects of CRLI, insurance can be the formidable wall. You may have to pay a premium for your uniqueness. IF someone will insure you. Take heed. There are Motorbike advocates and Trike advocates. Each design has inherent advantages and disadvantages. High-speed folks generally prefer the Motorbike design. Twin-steered wheels up front means positive steering traction on corners and stable braking in fast stops. The MBG prototype is a Trike configuration and its advantages are strongly tied to the body design (more on this later). If you list what's important to you, the basic design you use, Motorbike or Trike, is usually quite clear. The Hybrid Configuration Why hybrid? Why the need for so many energy sources? Admittedly, hybrid sources increases complexity, initial costs, and overall vehicle weight. I offer these points in favor of a hybrid configuration. 1. Different energy sources are both available and most useful at different times. You, not the vehicle, know how far you're going. You can select the appropriate source for the task. 2. All sources have inherent advantages and disadvantages. Utilizing two or more sources frequently adds the good features of each source and offsets the shortcomings inherent in any one source. 3. Hybrids may increase vehicle reliability. In short, if a part fails or becomes inactive (discharged pack, out of gas, etc.), you may still get home. This is not inherent to hybrid usage. Take care not to compromise the capacity for independent as well as complimentary operation of the sources you select. 4. Combining sources ensures that propulsive power is always available. Here's more detail on the MBG's four energy sources-- batteries, OCU, photovoltaics, and regenerative braking -- and their functions: Batteries Initial design of the MBG prototype calls for three onboard sets of batteries to serve propulsion, control and instrumentation, and regeneration tasks. a. PROPULSION pack. Eight 12-volt, lead-acid batteries at 100AH capacity each. These are wired to a series/parallel arrangement of 48 or 96 volts and used with a 5-stage in-line resistive controller. b. INSTRUMENTATION pack. A dedicated NiCad pack for instrumentation, communication, microprocessor, and cooling system pumps and blowers. Rated 12-volt at 20 AH. c. REGENERATION pack. A NiCad pack for regenerative braking energy. Designed to store the energy generated by a full stop from 55 mph. Wired for series-parallel arrangements of 24 and 48 volts. Rated 48-volt at 3 AH. These battery packs can make use of one or more sources of EXTERNAL power (power from a utility grid or standby generator) or ONBOARD power -- OCU, photovoltaics, and regenerative braking. EXTERNAL power, utility-supplied or an owner-operated standby generator, will charge the Propulsion pack through a simple bridge rectifier. One benefit of a 96-volt propulsion system is that direct charging from utility power (or a 110-volt AC generator) is possible without a battery charger. For example, a 20-amp outlet will replenish the MBG's propulsive batteries in less than 5 hours. The timer and rectifier are carried onboard, cost $20, and weight less than 2 lbs. The Instrumentation pack is also chargeable from utility power via a small battery charger (also carried onboard). Onboard Charger Unit OCU (Onboard Charger Unit) power is available via a small engine- generator unit. As detailed in the first Home Power article, this provides power at a constant rate for direct use in the motors, for storage in the Propulsive battery pack, or both. By manual selection, both the Instrumentation and Regeneration pack can be recharged by the OCU via their respective onboard battery chargers. Two engine-generator combinations will be tested for the OCU in the MBG vehicle. Both use an IC (internal combustion) engine fueled by gasoline. Eventually, this will be converted to propane or alcohol. An 8-HP horizontal-shaft Honda engine is the present choice. One test bed will use a 110-volt ac alternator as the generator part of the OCU. This is a standard package: a 2500-watt unit. Its output will be directed into a transformer to supply full rated wattage at either 60 or 120 Volts after rectification into DC. This arrangement ensures that the OCU will "follow" the propulsive pack through its two arrangements, 48 and 96 Volts, during vehicle operation. The other test bed will use a ganged set of special-built PM generators, shaft-to-shaft coupled to themselves and the IC engine. One of the PM generators serves double-duty as the starter motor for the OCU. Each PM generator produces 1,250 watts at 3,600 RPM, and is wired in series or parallel with the other for the needed 60 or 120-volts output. The OCU engine will have manual linkage to control engine speed, with settings for idle (warm up), 3/4 speed (half power), or full speed (rated power). The Onboard Charger Unit (OCU) wears many hats. It operates as a battery charger (vehicle parked, propulsive effort low), a primary source of power (propulsive effort high, i.e., acceleration, hill climbing, freeway speeds), the sole source of power (battery pack depleted, vehicle stopped), an emergency source of power (for drills, lights, motors, or 110-volt ac loads through an inverter, etc.), and as one way to provide vehicle cabin heating (through resistive coils, as in a floor heater). These are all potential side-benefits. For me, the OCU is there to give the EV range and to avoid the stuck-in-the-outback blues. Photovoltaic Panels PHOTOVOLTAIC power is used in the MBG vehicle as an energy source. It is designed to supply daylight power full-time to the Instrumentation battery pack. When this pack is charged, solar power is load-diverted to the Propulsive pack where it serves a battery maintenance function. In the MBG vehicle, solar energy is not supplying a significant amount of Propulsion power. This is not an intentional constraint. Photovoltaics have a place in the transportation scheme. However, while the solar car race in Australia proved that it could be DONE for propulsion, the pricetag is too high to call it "practical". Consider that the average entry used $4,000 worth of solar panels, $20,000 worth of battery pack (silver-zinc), and at least another $5,000 dedicated to motor, controller, and lightweight material usage. Solar-electric technology is most practical in EVs in the following applications: 1. A large, fixed array that charges an EV during daytime hours. Or charges a spare EV battery pack that can be exchanged with the one in the EV. 2. A super-lightweight vehicle (i.e., bicycle or tricycle) needing less than 1/2HP of power occasionally. 3. A small onboard system to help with battery maintenance, instrumentation and DC loads (lights, horn, turn signals, radio, wipers, etc.) control system power, thermal management (components, and driver and passengers), blowers, etc. It is this last function that photovoltaics serve in the MBG hybrid. I expect to have room for 120-160 watts of solar panels. Regenerative Braking Regenerative braking is a process whereby the energy normally consumed in braking the vehicle's momentum (as heat in brakes) is made into electricity and "recovered" for use. Electric vehicles are an ideal platform for this wizardry because their motors can be "wired as generators" during the braking effort, and the electricity can be stored in the battery pack. Thus, the energy of a moving mass can be reclaimed and will slow down the vehicle at the same time! It's wonderful theory but, in practice, regenerative braking in most electric vehicles is impractical because the application is plagued by a combination of these factors: a. Complexity of circuitry needed to quickly "re-wire" many motor types as a "generator" and maintain correct controller usage. b. Mismatch of voltages, currents, RPM, and load between motor and drive wheels throughout the speed range of the vehicle and a variety of braking conditions. c. Low efficiency of the regeneration cycle due to the accumulative inefficiencies of generating electricity, storing it, and then using it. Batteries involve an electro-chemical conversion that occurs once during charge and again (reversed) on discharge. Losses occur in both phases. Regenerative braking in the MBG design is more practical than most EVs because it circumvents these obstacle in the following ways: a. The MBG involves relatively low-density power conversion. Lower electrical currents ease switching issues. b. PM (permanent magnet) motors readily convert from a "motor" to a "generator" configuration. c. PM motors are efficient as motors or generators. d. Power from regeneration is stored in a variable-voltage, high- efficiency battery pack. Nickel-Cadmium batteries are more efficient than lead-acid batteries. The KEY ingredient is the dedicated battery pack for regenerated energy. This bypasses the complexity of circuitry surrounding the main propulsive battery pack. A big plus is the variable voltage of the NiCad pack (series or parallel of 48 or 24 volts). It permits easy voltage/load matchup as vehicle speeds and braking needs vary. The energy salvaged during regeneration is used immediately in the next startup of the vehicle from a dead stop. With the first pressure on the accelerator pedal, the Regeneration battery pack is connected directly to the motors in the 48-volt configuration. Once a preset level of discharge is reached, this pack is disconnected and the main propulsive pack engaged. An unexpected bonus to this circuitry is that the Regeneration NiCad pack partially alleviates the voltage spike and high energy consumption attributed to stall motor current, a condition that exists at vehicle startup. Some voltages or vehicle speeds are too low to provide "recoverable" levels of electricity. However, this low-grade electricity can be channeled into resistive coils (like those found in floor heaters) to continue the braking effect. This is called dynamic braking. The use of dynamic braking minimizes the amount of hydraulic braking required to slow the vehicle. Also, both drum and disc brakes release asbestos dust to the environment as the brakes wear. Dynamic braking decreases asbestos pollution by reducing the rate of brake wear. Your pocketbook will appreciate the greater time between brake jobs, too! Both the regenerative and dynamic braking circuits are made to work off the standard brake pedal in the MBG. As the pedal is depressed, it moves through various detents. The regenerative braking circuit uses the first two (1 and 2) detents and dynamic braking uses the following two (3 and 4). Further pedal depression engages the vehicle's hydraulic brakes. Indicator lights on the MBG dashboard will inform the driver when regenerative, dynamic, and hydraulic braking modes are engaged. The braking effort, then, is completely under the control of the driver; he or she simply presses the pedal until the desired degree of braking effort is reached. There's one more feature here: coast versus slow down. In standard cars, when you take your foot off the accelerator pedal, some vehicle slow down occurs automatically. This is due to "compressive braking", an engine- related retardation of timing. This is pollution intensive, but a good safety feature because it acts like a "dead man switch". An electric motor cannot be compressively-braked. To duplicate this slow down feature, the MBG's motors are automatically put into a dynamic braking mode when the accelerator is released. Long-time EV Owners advocate the benefits of "coasting" in electric vehicles. Little wonder! It certainly increases vehicle range! It takes practice to anticipate traffic and stoplight timing, letting off on the accelerator pedal to take upmost advantage of this effect. But it pays off. I like this feature, too. So, the MBG will have a dash-mounted switch to defeat the "auto-slow" circuit described above. When selected, it permits the maximum coasting effect, letting vehicle speed bleed off to the natural resistance of bearings, tires rolling on a surface, and general aerodynamic losses. Instrumentation & Controls The MBG prototype will be equipped with lots of monitoring capability. So that the dashboard doesn't look like the cockpit of a Boeing 747, a microprocessor will be used to automatically scan through all of the onboard sensors (i.e., voltages, currents, temperatures, etc.). An audio and/or visual indicator will alert the driver of any parameter that moves outside the range of preset values, and display the errant reading for further evaluation. I prefer this system to idiot lights or gauges since I always seem to notice them too late! This may be too costly to include in a production version. Aerodynamics A standard car, speeding down the highway at 55 MPH requires fully 50% of its propulsive effort to move air aside. As more attention is given to the ways a vehicle can slip through the air, this power consumption is reduced, as is the need for the size of propulsive machinery. There is no mystery to this (we wouldn't have aircraft that could do 2,000 MPH if there were) but, for a long time, solid aerodynamics has been lacking in most cars. The main culprit is "style", truly aerodynamic vehicles are thin and taper at each end. Since we are quickly reaching the point where conspicuous consumption of fuel is no longer possible, the "style" is getting cleaner, softer edges, lean lines, recessed fixtures, and more attention to detail. However, there's a lot more "trend" than "slick" in most manufactured bodywork. What are the important aerodynamic considerations in landborne vehicles? A brief but accurate list includes four factors: shape, frontal area, closure, and ground effect. The ideal SHAPE of vehicles in the 0-60 MPH range is a teardrop, rounded at the front and slowly tapering to a point in the rear. FRONTAL AREA is the number of square feet of silhouette when the vehicle is viewed "head on". You want this as low as possible, suggesting that the vehicle be a thin teardrop. Exhaustive tests have concluded that unless the CLOSURE (the way the vehicle tapers in the rear) stays at less than a 14 degree angle (7 degrees each size of a centerline through the vehicle), you might as well chop it off abruptly. Rattail-looking vehicles have limited appeal, so you'll see mostly sharp cutoffs. GROUND EFFECT, in this context, defines a natural relationship between a road surface (or any surface) and the sky. A vehicle interacts with, and generally messes up, this intimate relationship in a way that defies easy description or remedy. It gets progressively worse with speed. Vehicles minimize the resultant drag with SKIRTS (shrouding that dips down to the surface to keep air from getting under the vehicle), UNDERPANS (smooth bottoms that minimize the yo-yo'ing of air between vehicle and ground), and ISOLATION (maintaining an elevation above the road surface that fools the road surface into thinking your car is an airplane). A measure of a vehicle's aerodynamics is its drag coefficient. (This is not directly affected by the vehicle's propulsive power or its weight.) The desirable value of drag coefficient is low. Streamlining is the art of achieving a low drag coefficient but it is thwarted by the air's propensity to cling to a surface. When it does, the air is turbulated at the parting, rolling and dodging, producing a thing called a vortex that's a real drag to the vehicle that experiences it. Careful attention to the four factors above, a clean shape, low frontal area, good closure, and minimal ground effect, will help. The MBG vehicle chops the typical frontal area of a passenger vehicle in HALF. One MBG prototype will be a single-seater, so no explanation is required for how this is achieved. However, the second MBG will be a twin-seater (one driver, one passenger). It will also have HALF the frontal area of a standard car because the passenger is positioned behind the driver. This is called tandem seating. An alternate arrangement is "offset tandem", which places the passenger behind and slightly to the right of the driver. This would result in a slightly greater frontal area but afford the passenger a direct view ahead instead of a "view of a head". The MBG prototype will have a low drag coefficient because of a painstaking attention to detail. For example, there will be no scoops. A scoop is a protrusion that is intended to force some of the air moving past the vehicle to enter and, hopefully, move through some portion of the vehicle. Scoops are used for ventilation (of driver and passengers), combustion air (for engines), and cooling air (thermal management) -- the latter application typically requiring the highest CFM (cubic feet per minute) of airflow. Scoops interfere with aerodynamics. An alternate technique is to identify high and low-pressure points on the vehicle's body, and position inlets and outlets at these points for any internal cooling needs. As well, one test bed will investigate an alternate cooling technique for engine, motors, and batteries to eliminate most inlets/outlets. Various aspects of the specific body layout also help to keep the drag coefficient low in the MBG vehicle. However, since these are side benefits of the vehicle's crashworthiness, they are better revealed in the next section. Crashworthiness If a transportation system were proposed today that killed 25,000 people worldwide each year, and injured or maimed another 2 million human beings annually, we'd reject it out of hand, right? I guess not. That describes our current system using automobiles! A major concern and design effort must be expended in scratch-built vehicles in the area of crashworthiness -- the effect of collision from the front, side, or rear of the vehicle. This could be a two-vehicle interaction or a collision involving the vehicle with a stationary object. Although this subject is important in the design of ANY type of vehicle, it is especially important in lightweight vehicles because it is a basic LAW of physics that more of the energy of a collision is transferred to the lighter of two vehicles. Weight is a linear function. Speed is a square function. At twice the relative speed of collision, the effect of the collision is four times as great. In view of this, if you're neurotic, you don't drive. If you're sane, you drive as little as possible. If you're cautious, you drive something slow and heavy. If you concede that life is all about risks, you drive small and lightweight and stay very, very alert. If you're building your own, stay aware of things that help: strength, collapse distance, and design. In vehicles, STRENGTH is often confused with weight, massiveness, and metals. Carbon fiber and fiberglass materials, and composite construction (fiberglass sandwiching) techniques make a lightweight vehicle tough. Stronger, in fact, than a vehicle several times heavier. COLLAPSE DISTANCE recognizes the importance of spreading the impact of a collision over the greatest amount of time possible, decreasing the RATE of energy transfer. All that sculpting of metal that occurs in vehicle crashes actually helps the occupants. It dissipates energy. It slows things down. It converts energy into noise, heat, and motion. The idea is to absorb energy that a softer body, like a human being, dissipates in a more messy and irreversible fashion. Good DESIGN confronts the possibility of a collision from any direction. It figures out how to be tough, malleable but rigid, dissipating and slowing energy. You do NOT worry about what happens to the vehicle. Every reasonable effort is made to keep a careening car or a telephone pole from penetrating or malforming the driver/passenger space AND it occupant(s). Lightweight EVs, with their fiberglass materials and long aerodynamic bodies, are typically a designer's nightmare when it comes to crashworthiness. Front and rear impact are relatively easy directions to fortify. Side impact is the tough guy. How can you be slim and still withstand a side impact? The MBG vehicle incorporates a TRIKE layout, as shown. In my opinion, this is one of the very best when it comes to overall collision protection and, most importantly, side impact protection. The MBG vehicle (see diagram) borrows heavily from the Amick windmobile (pictured in last month's issue). Note that, in this layout, a side-impact will first contact the vehicle some 1-1/2 to 2 feet away from the driver. Due to the vehicle's unique wing-like structure and the rear wheel housings, this would be a tough distance to collapse. At least, it will dissipate much of the collision energy. Then, simply because the vehicle is so lightweight, the vehicle will start sliding. Certainly, at lower vehicle speeds, this will occur before cabin penetration. The end result is a greater degree of survivability, since the collision energy is spread out over both distance and time. Note: One individual challenged this last statement, questioning the use of the word "survivability" since, almost assuredly, the vehicle in question would go careening off to collide with something else. Without any thought at all, I responded, "That's okay. I'd love to be in a position to worry about the second collision!" That still fits. I don't expect absolutes and, like life, I'll take things as they come. The MBG, then, uses a Trike arrangement, utilizing twin motors, one at each of the rear wheels. This eliminates the differential -- with its attendant weight and inefficiency -- as required in vehicles using one propulsive source, i.e., an engine. It's likely that the MBG motor/wheel assemblies will use fixed gear ratios, eliminating the weight and inefficiency of a transmission. The motors act independently of one another. So, one motor will bring you home if the other decides to play dead. The MBG vehicle is similar or different to the Amick windmobile in several ways. More specifically, the MBG prototype: 1. is NOT designed to use wind as an energy source. In the area I intend to operate the vehicle, there just isn't enough side wind to justify using it. Accordingly, the arch is lower. This will keep the wind's effect to a minimum and decrease the frontal area. 2. has a vertical fin between the uppermost point of the arch and the vehicle body. The arch is already a natural roll bar, and this fin strengthens this feature. It also stiffens overall structural support, increasing the side-impact protection. While this will affect the aerodynamics a bit, it also means that a side-impact must collapse the horizontal lower wing (compressive), the arched upper wing (compressive), the vertical fin (shear), and the wing which is attached to the outermost point of the horizontal wing on the other side of the vehicle (expansive). 3. has a narrower fuselage. As much as 9-12 inches in the width of the center vehicle body is removed since no true collapse distance need be added around the driver. This would decrease frontal area, assist with a proper tapering closure, and lower the drag coefficient. 4. has a flattened arch. This makes it able to accommodate rigid photovoltaic modules. 5. has, when viewed from the side, the arch angled backward. This retains the crashworthiness of the horizontal low-wing positioning (aligned to the driver) but permits better side visibility for the driver. 6. employs the arch as a means of promoting high visibility of the slight- figured MBG body. The overall MBG design, incidentally, helps drivers "see" in front of the MBG because there's so little of the MBG body to interfere with their view! 7. may use the arch as a "radiator" in MBG proprietary thermal- management system. How safe is safe? Buying a big, heavy car might exorcise your fears about collision, but ... will it? In any car, how much distance is there between the driver and the front end of a car that hits the vehicle on the left side? Think about it. A few inches. It may be good steel but there's going to be "penetration" and all of its nasty consequences. In this case, all of that fine steel everywhere else in the vehicle is working against the driver because it "plants" the vehicle massively (no pun intended), resisting the forces that would, for a lighter vehicle, cause it to start sliding. Final Comments I could go on and on. But -- it's time to zip this off to the Home Power folks. Besides, I've logged 22 hours on the Mac in three days doing this thing, and the key cooling system is going to come on at any second. It's writ-and- rewrit, edited and rearranged. A blackout right now would ruin the elation I feel in doing and finishing it. I've given up a lot of my gameplan for the MBG in this article and that makes me happy and sad. Happy because experience, like love, is something you can share without using any of it up. Sad because I'd like to make a million dollars and finish the MBG, and I can't sell what's in the public domain. Oh, well. The first article in Home Power #8 generated bushels of mail. Thanks! That's a welcome stroke. (I sometimes wonder if I sail strange seas of thought alone.) The EV networking newsletter is evolving into what may be a magazine (tentative title is Alternate Transportation Magazine.) EVs and HPV (human-powered vehicles), airships and ultralights, solar cars and waterbuggies. Shooting for a March release, newsletter or mag, of the 1st issue. Do you feel teased into building your own hybrid EV. Great! Give it LOTS of thought, glean every bit of info you can from anyone who is doing anything that looks interesting, and go at it. Please -- be careful. Too little knowledge is SO dangerous. None of what is written here is gospel truth. I'm talking at the edge of integrating all this technology and I could get something wrong. Feel free to correct me, if you think I've done that. Be gentle; I have good intent. The final arrangement of this stuff -- into something you'll drive down the road -- is a process. Winnow through the factors and see what fits. Good fortune. Wait! Lead-acid batteries always take it on the chin when it comes to propulsive power packs. Okay, so they do have low electro-mechanical efficiency and low energy density. In a hybrid EV, they work adequately because there's less to do, and storage isn't an issue like it is in pure EVs. In the MBG, there is an OCU there to recharge them immediately. These factors tickle the thought that standard SLI (Starting-Lighting-Ignition) batteries COULD be used for the battery pack. Although not intended for deep-cycle, they are adept at the higher charge/discharge currents involved, and good performance may justify more frequent battery replacement. It's worth investigating! Want more info on electric vehicles? Here's some options: 1. Electric Vehicles: Design and Build Your Own , Michael Hackleman, 214 pages, 1977. $10 from Earthmind, P.O. Box 743, Mariposa, CA 95338. 2. EV Sources & References. Lists publications, catalogs, manufacturers, and sources for components related to EV vehicles. Send $3 to Michael Hackleman, P.O. Box 1161, Mariposa, CA 95338. 3. EV Mailing List. Get on my mailing list for information on Alternate Transportation Magazine, Video Lending Library of EV films, and EV documentary film (now in postproduction). Send an SASE or postal money to Michael Hackleman, P.O. Box 1161, Mariposa, CA 95338. Sweet, colorful, detailed visions! Michael Hackleman