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Electric Vehicle Conversion/Technologies

Note the presence of hazardous materials and conditions that must be approached with proper precautions and procedures to avoid damaging, injurious, or even fatal consequences.

Battery technologies
Considerations
 * Life cycle cost
 * Initial cost range
 * Energy density
 * Peak power capacity
 * Internal resistance
 * Voltage depression
 * Maintenance
 * Available form factors
 * Expected degree of discharge
 * Low temperature operation

Lead acid
Lead acid cells are sensitive to "break in", in that severe use early in life can shorten the lifespan. They are also sensitive to temperature, with low temperatures severely reducing the amount of energy available - sometimes battery heaters and insulated boxes are appropriate use in cold climates. If sufficiently discharged the electrolyte can freeze at extremely cold temperatures, which can break the case from expansion.

It is important that lead acid cells be kept charged. A deep discharge without an immediate recharge can significantly reduce the capacity of the batteries. Lead acid batteries also give the most total energy throughput over their useful life if the discharge cycles are relatively shallow, but such repeated shallow discharging can reduce the total energy available between recharges. The electrolyte is sulfuric acid in water and is not especially strong but is hazardous to skin, eyes, and clothing and corrosive to steel and aluminum. It does not affect most plastics and stainless steel. It is easily neutralized with common baking soda (sodium bicarbonate), which should be kept available near the batteries. (Note that a common "dry powder" fire extinguisher is charged with sodium bicarbonate and is appropriate for use on electrical equipment.) When combined with the acid it will evolve carbon dioxide, leaving a relatively harmless sodium sulfate residue. When working on the batteries some baking soda should be kept at hand in case of an electrolyte spill. Safety glasses should be worn when working near or upon the batteries. Sometimes acid will leak from the seal between the top and the case, or may be spilled when moving or testing the batteries. Such an acid leak can not only corrode the vehicle's structure, it can also cause a highA–resistance current leak, which can cause some types of battery chargers to fail with a ground fault. In the case of an acid spill, battery cases and tops should be wiped down with a solution of water and baking soda. This should be repeated until no bubbles of carbon dioxide are seen.

Discharge and failure to recharge will cause sulphanation, a chemical change on the surface of the plates that reduces capacity and increases internal resistance. Keeping the battery properly charged and well watered (where appropriate) is the best care to ensure long service life. Overcharge of some types of batteries can also be harmful.

If the battery is not likely to be used and quickly recharged it should be placed on a "float charge", where the charger applies a voltage that will not cause overcharging (which is harmless to wet cells but consumes the water in the electrolyte through electrolysis into hydrogen and oxygen and is damaging to other lead–acid battery types).

Batteries in general, and lead acid in particular, will sustain a greater lifetime energy throughput if only partially discharged, generally less than 50 percent being considered an economical design point. As lead acid batteries in particular have a high weight for a given capacity, and this weight must be hauled by the vehicle, it becomes uneconomical in energy to have much excess capacity, but since the greatest expense is not energy cost but rather battery replacement, the main effect of having too much battery weight will be in its effect upon acceleration performance and brake wear.

Flooded lead–acid
Batteries suitable for EV conversions are typically sold as "golf cart" batteries and offer the lowest initial cost per watt-hour of capacity, high watt–hour capacity and reasonable life when properly cared for. A typical configuration is a six volt battery containing three cells. They are also available in 4-cell, eight volt configurations but these are rarely used in EV conversions owing to a higher total life cycle cost. Flooded lead–acid batteries are conditioned periodically by overcharging to equalize the state of charge of individual cells in the pack. Care must be taken when charging batteries indoors due to the creation of potentially explosive hydrogen gas. If such cells are charged in an enclosed space the charging station (or other switched outlet) should also be connected to a vent fan of appropriate size and location. Being "wet" cells they require maintenance in the form of addition of distilled water, or the addition of a Hydrocap™ - a catalytic device that recombines evolved hydrogen and oxygen, reforming the water that would otherwise have to be replaced. When these caps are used the temperature may be monitored to good effect; when all cells are fully charged, all of the caps will be warm from the exothermic recombination of hydrogen and oxygen to water. Devices can be purchased that allow fast and easy central-point watering of the batteries, if catalytic recombiners are not used.

Wet lead–acid cells will also shed material from their plates, which accumulates at the bottom of the cell. Cells intended for long service life and deep discharge have extra space to accumulate these materials. When the accumulation reaches the plates it will cause a (non-catastrophic) short circuit, eventually rendering the individual cell useless.

This type of cell is particularly resistant to overcharging, since the dissociated water vented as gas may be replaced, or recovered using a catalytic cap. This type is less resistant to vibration than other types and the entire pack will become useless if the electrolyte in a single cell is lost due to case damage, which by not allowing current to flow through the cell will bring the entire vehicle to a halt.

The flooded lead acid cells used in EV conversions are readily available at low cost compared to other batteries owing to their high volume use in other vehicles such as golf carts. These batteries tend to have high weight in proportion to their peak capacity and a higher internal resistance than other lead-acid types. Owing to the lower voltage in a battery unit (three cells with a nominal six volts) it is not practical to build a high voltage light weight battery pack. Thus the advantages of the wet lead-acid cell are best exploited in a light truck conversion and in lower voltage automotive applications (96 volts or less using six volt batteries, or 120 volts using eight volt batteries) in lighter vehicles. Note that for certain battery voltages and sizes (e.g. the six volt Trojan T-105) the actual purchase cost can be significantly lower that for other related batteries (e.g., the 16% heavier Trojan T-145), due to the highly competitive golf cart market. Batteries using tapered post connections are generally considered better than batteries with other connection arrangements such as vertical stud, owing to the greater contact area and less tendency to loosen in service as a consequence of plastic flow of the lead. The more expensive cable to post connections will add to the total cost, however. If the stud type is used a small amount anti-seize paste (typically used on exhaust manifold bolts) consisting of aluminum flakes in a grease carrier, should be applied to only the stud threads before assembling the connection, keeping the electrical contact area clean.

Batteries intended for automobile starting are not suitable for use in EVs as they are optimized for a different charge-discharge profile and their short service life in this application will greatly reduce their cost effectiveness.

Wet lead acid cells offer a high ampere-hour capacity compared to other types, 225A·h being common in golf cart types. The 225A·h refers to a twenty hour discharge rate and the actual energy available under typical electric vehicle conditions will greatly reduce the total energy available from this type.

Periodically the battery pack should be given a balancing charge. For such a charge the charging voltage is increased to a value that will cause fully charged cells to electrolyze the water in the electrolyte. Any cells not fully charged will continue to charge. Note that this can only be done with the wet cell type as this procedure will damage or destroy other battery types.

A well cared for flooded cell pack in normal light truck service is generally expected to last about three years. It may be possible to extend this life through electrolyte treatments, an option not available with other lead–acid battery types. Buildup of shed plate material below the cell will limit the ultimate life of the battery.

The few major brands available for this type of battery use different connection locations and so the vehicle may require new cables if the type of batteries installed are significantly changed. Many house brands of batteries will use one of the few major manufacture's form factors.

Absorbed glass mat (AGM) lead acid
Compared to wet lead acid these cost far more, have shorter life, far less ampere–hour capacity, but much more maximum power output per unit weight, greater durability, and lower maintenance requirements. Owing to their high output and lower weight per cell this type is particularly suitable for high performance vehicles, being commonly used in electric drag racers and low cost sports cars. Some configurations have been optimized for light weight electric vehicles, offering 12 volts from six cells in a 45 pound (20 kg) package, but only 55 A·h at a slow discharge rate. This type of cell offers low internal resistance and so batteries made from these cells can deliver high power outputs for their size and weight. While substantially more expensive both per ampere-hour and in lifetime energy throughput than wet lead-acid cells they are still considerably less expensive than other types of batteries.

This type is suitable as a replacement for wet cells but must be carefully protected from overcharging as there is no means for replacing lost electrolyte water due to outgassing. The ability to mount these batteries at an angle may be an advantage in some smaller vehicles. The leading developer of this type of battery, Optima, was purchased by Johnson Controls and folded into their Interstate battery group. Subsequent problems with new dead batteries (palette load shipments) have been reported on some electric vehicle forums.

Lead acid gel-cell
Gel cells are sealed and the electrolyte is non-liquid. This requires that they be operated and charged within carefully controlled ranges to avoid overcharging. They are also unsuitable for the high-current requirements of a typical direct current application. They are suitable for low current high voltage applications such as is typical in an alternating current system. Gel cells are commonly used in electric bicycles and scooters, and in computer uninterruptible power supplies. This type of cell has been used in CalCars' plug-in hybrid conversion of a Toyota Prius, but is intended only as proof of concept for that application owing to its weight compared to other technologies. While infrequently used in EV conversions this type of cell is available in a wide variety of battery shapes and sizes and this is advantageous if battery space is limited. As many of these batteries have limited total power and current capacity they are sometimes used in parallel groups (called "buddy batteries") to construct a pack. This type is more sensitive to damage by incorrect charging profiles than is the AGM type. As the gel immobilizes the electrolyte it is not subject to stratification as is the wet cell type. The gel makes overcharging particularly destructive to this type of battery since any evolved gas bubbles (hydrogen or oxygen) will remain at the surface of the respective plate and so prevent electrolyte contact and hence can severely reduce the storage capacity of the battery. Gel-cells are used in the Solectra Force, a commercial conversion of the Geo Metro that is no longer in production.

Valve regulated lead acid (VRLA)
A version of this battery by Panasonic was used in General Motors' EV1 electric vehicle, and a version by Delphi in Ford Motor Company's Ranger EV. As with most other batteries, careful charging patterns are required to avoid overheating or loss of electrolyte. VRLA batteries contain catalytic materials to recombine evolved hydrogen and oxygen back into water before they escape to the atmosphere.

Foam plate and anti-sulphination coatings
A recent development the carbon foam grid was initially developed by Caterpillar Inc. in an attempt to create a more robust battery for use in grading and construction equipment. Such equipment is often inactive during a portion of the year and is subject to strong vibrations when in use. This environment will require the frequent replacement of lead-acid service batteries. Carbon foam was being investigated by Caterpiller [for use in radiators when it was noticed by an in-house battery investigator and subsequently applied for use in the cathode and anode plates of flooded lead acid wet cells. The carbon foam has a very good resistance to repeated bending (a high fatigue life) and a very large surface area, both beneficial to Caterpiller's battery applications. A spinoff company, Firefly Energy was created for the commercial development of this technology. The first commercial product of this effort, a Group 31 truck battery, is expected in 2008, will be sold under the Oasis brand. As trucks are needing considerable energy for "hotel" loads to operate sleeper cabs when the truck is not in use the application is more akin to that of a deep-cycle marine battery rather than that of a simple vehicle starting load. The expectations are that this new battery have better than 40 percent additional capacity and will allow up to 800 full recharge cycles compared to the typical 200 cycles for a conventional Type 31 truck starter battery, and this while replacing only the negative plate with carbon foam. A more advanced application will replace also the positive plate, with projections that at least a third of the weight may be eliminated for the same storage capacity. Special coatings have also been developed by Firefly that reduce the sulfination effects of long discharged times. It is unlikely that batteries specifically suitable for electric vehicles will be available before 2010, and the current Group 31 battery will initially be available only for fleet use. Given the expected performance and cost parameters of this technology there is considerable interest in these developments within the EV conversion community.

Nickel cadmium (NiCd or "Nicad")
The nickel cadmium cells suitable for EV use are "wet" or "flooded" cells. The cadmium in a nicad is particularly toxic, far more so than lead. The battery does not use an acid electrolyte but rather a base, potassium hydroxide also known commonly as lye, used in processing food, making soap from fat, cleaning drains and many other applications. The electrolyte is hazardous to the eyes and can burn skin but is easily neutralized with common vinegar, which should be kept available when performing battery maintenance. Unlike acids, bases do not attack steel but are extremely corrosive to aluminum.

For long term use the higher cost may be well repaid owing to longer life. NiCads will typically have about 50% more energy for the same weight than lead-acid, and can be safely discharged to very low levels. Most wet Nicads also are said to lack "punch", not having the ability to supply high currents seen from AGM lead-acid cells.

Nicads also exhibit "memory", requiring periodic deep discharge (usually a series of three full discharge-recharge cycles) in order to regain battery capacity

This type of battery was applied commercially in the Th!nk City EV.

Nickel metal hydride (NiMH)
These have been used in some production vehicles such as some versions of the Chrysler TEVan, Ford Ranger EV, GM EV1, Honda EV Plus, and the Toyota RAV4 EV. They are also used in most hybrid vehicles, Their use in hybrid vehicles may result in substantial reduction in cost over the next few years (written 2005). As is well known by cell phone and some digital camera users these batteries have a high self-discharge rate.

Lithium-ion (LiIon)
These offer the highest energy density commonly available, although at substantial expense. They were used in the Nissan Altra electric vehicle. They are currently not cost effective for most converters but the technology is developing rapidly and this type is being used in portable power tools. Previously available versions of this type of battery would degrade over time even if not frequently cycled - exhibiting a" calendar life". Improvements are expected in the near future as indicated by the recent development of enhanced versions of this type specifically for application in hybrid vehicles by Panasonic. This type will be used in a third party conversion of the Prius hybrid to create a plug-in hybrid, expected to be available in 2006.

A new development in lithium-ion technology may be promising to EV conversion. A123Systems claims their new battery technology delivers up to 10X longer life, 5X power gains and five minute recharge. This new product also boasts a significant cost and weight savings vs. NiMH or conventional Li-Ion technology. The price seems comparable to high end lead acid batteries with developer kits available. Homebuilders should be cautious of new technologies however until the product is in the marketplace for some time. Dewalt will be offering this technology beginning in 2006 so this should give real world testing of this battery

The Tesla Roadster will be powered by LiIon, with a range over 200 miles, 0-60 mph in 3.9 seconds, and top speed of 130 mph.

Pack sizing
Several considerations apply to selecting pack capacity, particularly when lead-acid cells are used. Lead-acid cells tend to degrade in capacity in a predictable manner. If the pack is undersized for the application it may perform satisfactory for a time, but due to loss of capacity may not provide sufficient range for its intended use, even though the batteries have substantial useful life remaining. Excess initial capacity will thus increase the service life of the pack. On the other hand, larger packs are not only more expensive, but have to be hauled, so excess capacity will both reduce economy of operation, acceleration and increase brake wear.

Pack voltage
Lightweight vehicles not suitable for freeway use will typically use 24, 36, 48, or 72 volt battery packs.

DC propulsion systems in EV conversions intended for freeway use will usually be 96, 108, 120, 144, or 192 volts. AC systems will usually be 192 volts or higher.

Using wet cell golf cart batteries
96 volts, obtained using sing sixteen 6 volt wet cells* (used in electric golf carts) and a nine inch DC motor in a light truck this will give sufficient performance for around town and for limited (but not hasty) freeway driving. The total pack battery, holddown, and cabling weight will be about 16×65 lb = 1040 lb (470 kg), representing a substantial reduction in the vehicle's useful load carrying capacity. The nominal watt-hour capacity will be 225×96 = 21.6 kW·h, with a practical yield considerably less than this value. Nominal specific capacity is 20.8 W·h/lb (45.8 W·h/kg). With sufficiently high (120VAC mains) it may be possible to use a simple non-isolated charger to charge 18 batteries for 108 volts nominal. An 18 cell pack using Trojan T-145 or equivalent will offer over 140 percent of the system capacity of 16 T-105 or equivalent, for a substantial increase in range with about 130 percent of the weight. The higher capacity batteries will be less cost effective (by a factor of about.92), due mostly to the larger volume demand for the popular T-105 type.

 * Calculations based upon Trojan-T-105 with two pounds allowance for cable and hold-down.

Using AGM batteries
With a light vehicle and eight 12 volt AGM batteries the performance should be substantially improved and quite suitable for short range use. Note that AGM batteries have a substantially higher peak current capacity and lower internal resistance than wet cells. The total pack battery, holddown and cabling weight will be about 8×46 = 368 lb (167 kg). This lower weight is much more suited to a lightweight vehicle than are the wet cells described above.

 * Calculations based upon Optima D34/78-950 (yellow top) with two pounds allowance for cable and hold-down. Use of blue tops would result in a pack weight of about 8×62 = 496 lb (225 kg).

120 and 128 volts
These are configured using twenty 6-volt, ten 12-volt, or fifteen 8-volt (wet cell golf cart) batteries. These configurations were rare since other equipment (the pack to 12-volt converter) was not easily available in these input voltages, a problem now solved by some vendors. 120 volts is especially attractive since a pack may be constructed with twenty six-volt batteries. As suitable wet cell traction batteries in quantity are packaged as pallet loads of 40, two vehicle owners may purchase and divide a pallet with no leftovers. Since common controllers will typically operate between 96 and 144 volts the controller is not operating at the upper limit of its voltage range.

144 volt
Under similar circumstances this should enable a DC conversion to operate with the acceleration normally obtained from the ICE original. If the same battery types are used one could expect about 40 percent additional range compared to a 96 volt system. Note that if six volt wet cells are used the additional eight batteries will weigh an additional 560 pounds (250 kg), representing a substantial decrease in load carrying capacity and in economy of operation. If more advanced battery technologies are used then the performance penalties are substantially less.

Using the popular Trojan T-105 battery a pack of 24 batteries (exclusive of cabling and tie-downs) would weigh 1392 lb (672 kg).

Where this voltage is desired in a somewhat lighter and more compact wet cell pack it may be constructed using eighteen 8 volt batteries. Using the Trojan T-860 a pack would weigh 1008 lb (600 kg). As the T-105 and T-860 batteries are the same size, the total volume required by the T-860 would use considerably less volume, 75% of a pack built with the T-105 (but would have only 66% of the 5 hour rate ampere-hour capacity. The nominal capacity will be 21.6 kW·h, so this pack will have the same overall capacity as that of a 96 volt pack using 6 volt T-105s, but will  require two more battery stations. The added voltage will give an improved performance, but if used often that extra performance will have less range. As there is far less demand for eight volt batteries as compared to the common six volt golf cart battery, the cost per watt-hour stored will probably also be higher.

144 volts is also a common upper limit for voltage applied to certain commonly available mid-priced controllers such as some models of the widely used Curtis. Owing to the current limitations of that controller the main effects compared to lower voltage systems will be to increase the range and to ensure effective performance at deep discharge levels. Effective exploitation of the higher voltage to obtain increased acceleration requires the use of a specialized high-current controller, such as the Zilla.

192 volt
This is becoming the conversion industry standard for high performance street vehicles such as sports car conversions. This voltage is not typically used with large wet cells due to the high weight of the total battery pack (32×70 = 2240 lb, about 1000 kg), Instead usually either AGM lead acid (740 pounds or 340 kg for Optima Yellow Top) or wet cell NiCads (908 lb or 410 kg for SAFT STM).

Higher voltages
Higher voltages are used in specialized vehicles such as drag racers and for some AC motor conversions. Since high voltage systems use substantially less current it is possible to use gel-cell lead acid, unsuitable for higher current applications as they are subject to permanent damage at high current flows.

Balancing circuitry
Most performance systems use other than the "flooded" wet-cell golf cart batteries. Unlike the robust golf cart batteries it is not practical to rebalance the pack by overcharging as this can damage the batteries. Instead, additional circuits and controllers are added to connect batteries to distribute the charge to cells that need it. These circuits are currently (2005) available only for 12 volt batteries. Note that individual cells within the batteries are not balanced by this circuitry.

Battery charging
A charger appropriate to the battery technology installed must be used to ensure the maximum battery life.

While a charger may be installed where the vehicle is parked, most conversions use an "on–board" charger. Some chargers are "transformerless" and so are of light weight, but more sensitive to ground faults ( some of these may be avoided by a specialized charging circuit shown in a later section). Where a higher voltage (144 volts or more) is to be charged it may be most practical to divide the pack into two banks. These may then be charged using two 110 volt chargers, each of which uses one leg of a 220 VAC circuit (North American 220 volt circuits provide a two-way neutral that allows this).

A means of providing AC power to the charger is required. By providing an Avcon paddle port it is feasible to use power provided at malls and transit stations. Alternative methods allow the use of a long extension cord, either for home use or for "opportunity charging". Such opportunity charging must be done using a ground fault protected circuit with a properly connected ground wire.

If only a single 110 volt charger is used and it is desirable to use a public charging station then the builder should include a 220 to 110 volt transformer of sufficient capacity and appropriate electrical connections. The use of properly polarized "pigtails" (short connectors) or disconnect methods such as switches or switching circuit breakers must be used to avoid shock hazards. Do not attempt to design a connection system with "hot" male plugs.

Charging station
A charging station is a source of AC ("mains") electricity used to power the AC to DC converter (the charger), which is usually installed in the vehicle. Most home conversions use a high capacity extension cord (U.S. wire gauge 10 or 12) plugged into a ground fault circuit interrupter (GFCI). Some EV owners obtain a commercial grade charging station such as is used at malls and transit stations. Some transit stations also provide four wire "twist lock" sockets for use by EV users.

Series DC (direct current)
The most common motor and controller combinations are modifications of air cooled devices originally designed for use in electric fork lifts (Curtis). A system with air cooled components is simple to install and maintain but is not suitable for high power operations. Similar controller and charger designs with liquid cooling are available for street and also extreme high performance applications (up to 2000 amperes) ('Zilla). Liquid cooling of components is especially suitable where liquid cooling is to be provided for NiCad batteries during charging, as multiple systems can use a common circulating pump and radiator.

Advantages

 * Low cost
 * Simplicity
 * High starting torque
 * Does not require particularly high battery pack voltage, enabling use of low cost flooded batteries

Disadvantages

 * Electrical and acoustic noise from commutator.
 * Relatively inefficient compared to AC technologies.
 * Radio interference from controller, unless higher frequencies are used
 * Regeneration (battery recharging when slowing down) requires special design of the electronics to prevent excessive arcing at the motor brushes and overcharging of the batteries (Otmar). Although Curtis has designed and produces a regenerative DC controller for use in Europe, this model is not marketed in the United States.
 * Limited speed range requires the use of a multiple speed transmission, and so also (usually) a clutch, frequently eliminated in production AC motor designs.

AC (alternating current) Induction
The conventional alternative to DC.

Advantages

 * Quiet.
 * No wearout mechanisms (i.e.brushes). No regular maintenance is required.
 * Efficient when cruising. Overall efficiency exceeds that of Series DC.
 * Effectiveness over large speed range allows elimination of transmission shifting, but with an overall performance penalty.
 * Does not have the unfortunate failure mode of DC motor controllers of failing fully ON.
 * Regen is very simple, usually comes at no cost.
 * Use in newer commercial EVs will make this technology more easily available.

Disadvantages

 * More expensive, largely due to increased controller costs since there are typically three sets of regulating components rather than one as is used in DC systems. Most AC systems have been built by or for large corporations for research projects with little regard for price.
 * Lower startup torque due to controller limitations. Induction motors have a similar current vs torque curve to series DC motors, which would be available if the controller were built accordingly.
 * If no gear shifting is available it is important that the motor be speed-limited, which will limit vehicle speed to a maximum determined by the overall gear ratio and tire size. Single speed gearing suitable for high speed will limit low speed acceleration.
 * Higher voltage demands require smaller batteries which have a higher cost per Watt-hour stored, more battery box locations, and more cables and terminators

Permanent magnet
Permanent magnet motors are now being used for auxiliary motors, low-power motors for ultralight EV use, and as assist motor/generators in the newest hybrid vehicles such as the newest Lexus SUV hybrid vehicle. This type of motor is expected to be used in the recently announced 2006 Toyota Camry hybrid. The brushless type of this motor is controlled using controllers similar to those used with AC motors. With appropriate control circuitry this type of motor may be used as a generator for energy recovery during braking cycles. Conventional brushed motors use the magnets to create the stator field, with a commutator carrying current to the coils of the rotor. High performance motors for EV use will instead use the permanent magnets for the rotor, with multiple stator coils driven by the controller. This eliminates the use of brushes and the commutator, a great advantage in increasing reliability and reducing maintenance.

On Board or Towed Genset
A genset uses some kind of fuel to make DC or AC electricity which is wired to charge the battery pack and provide power for the car's motor. A genset trailer mounts the genset on a trailer towed behind the vehicle. Such a system is a Series Hybrid. There are several practical problems building a series hybrid using a small, cheap genset: The space, weight & money used by the generator system may actually be better used adding more batteries or improving the efficiency of the vehicle in other ways. Alternatively the money spent installing a generator could be spent hiring an efficient car for long trips. There has been at least one attempt to produce a commercial generator trailer, the Rav Long Ranger and a related project for the tzero. It wasn't based on a cheap off the shelf generator. A photovoltaic cell can also be used to increase the range.
 * It requires a lot of power to push a car at highway speeds, usually in excess of 10 kW. A generator big enough to give unlimited range at highway speeds must have a continuous rating greater than that required to push the car. Such a generator is usually expensive, large and heavy. A smaller generator will require periods of slower driving in order to catch up.
 * Most generators have no emission controls. The pollution caused by the generator over and above the pollution caused by an alternative vehicle on the same trip may exceed the pollution saved during non-assisted trips. This obviously depends on how bad the generator is and the ratio of assisted to non-assisted driving.
 * It is likely that any generator would have to meet the emission control regulations that apply to the vehicle's original engine.
 * Most generators are not very efficient. If trips requiring the generator are rare, running costs may not be a concern.
 * The connection between the generator and the rest of the system must prevent overcharging of the batteries and overloading of the generator.

Battery Trailer
A trailer packed with extra batteries is called a baset trailer.

Pusher Trailer
A pusher trailer is a trailer with a motor driving its wheels, which pushes the "towing" car. Such devices are usually made from the driving end of a 2wd vehicle, where the donor's original motor, emission controls and efficiency are retained.


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Electric Vehicle Conversion/Powertrain

Note the presence of hazardous materials and conditions that must be approached with proper precautions and procedures to avoid damaging, injurious, or even fatal consequences.

Motor cooling
DC motors will usually include an internal fan on the driveshaft end to move air through the motor from the commutator end. This will usually be sufficient for most vehicles. When such a motor is placed within a rear drive that is enclosed (such as a Volkswagen Type 3 with battery boxes around the motor), this can lead to overheating since the warm air is exhausted in the forward part of the motor compartment and so may be recycled through the motor. In this case, some form of partitioning and venting (perhaps using a motorized fan) is required.

As the motor is cooled by an internal fan attached to the mainshaft the motor should not be placed in neutral to coast downhill after an uphill run.

Motor to transmission installation
This is one of the key elements in creating a successful EV conversion. A poorly made adapter plate will quickly wear the transmission's front bearing, which will produce most of the driveline noise and which may lead to oil seal and/or gear failure.

The adaptation of the electric motor to the transmission uses two elements, a stationary adapter plate to connect the motor housing to the transmission housing and a rotating coupler to connect the motor shaft to the flywheel/clutch plate/pressure plate assembly (manual transmission) or the flex plate/torque converter assembly (automatic transmission).

The adapter plate
The adapter plate provides the union between the electric motor and the transmission. Some installations such as for the Volkswagen Beetle and similar use such a simple machined adapter that it is easily obtained at low cost from a commercial supplier. Adapters for more complex or less popular vehicles may be quite expensive. It is possible for the builder to construct such a plate using simple tools as outlined below, but a great precision in layout and fabrication is required. For this reason most converters purchase an adapter plate and coupling as a package from a specialty converter or have the plate fabricated by a professional machinist. If a flat plate is used, some means of properly spacing it must be employed, typically by using hollow tubular or billet stand-offs. More common will be the use of a stack of flat plates, forming an adaption between the large diameter of the flywheel and the smaller diameter of the motor, with interior volume to accommodate any projection of the flywheel forward of the face of the transmission (or bell housing if a separate unit is used).

There are only a few critical dimensions in an adapter plate. The overall length (the distance between the motor aft face and the transmission forward face should be accurate to within 0.25 millimeter. This is less critical than some other dimensions but the proper distance is required so that the clutch will operate correctly and so that the pilot shaft will enter but not bind on the pilot bearing. The most critical dimensions are those that determine the alignment of the transmission center to the electric motor/flywheel center. The error here should be no more than 0.001 inch.

Manufactured
For some installations, such as an early Volkswagen or Porsche, the adapter can be made as a very simple lathe turning with a few precision holes for mounting bolts, while other vehicles such as the Volkswagen Rabbit may use a single thickness of low cost aluminum plate.

For other more typical vehicles a more complex adapter is required A few specialty manufactures will manufacture a motor to transmission adapter plate by using a numerically controlled milling machine to carve an adapter from a thick billet of aluminum. Owing to a high materials cost and extensive milling time the purchase of a plate will be a substantial portion of the cost of materials for a conversion.

Fabricating from scratch, using two or three flat plates with spacer blocks
By careful layout and simple machining an adapter plate may be fabricated at relatively low cost compared to milling a thick plate. By using multiple plates with spacers a substantial reduction in materials and milling expense can be obtained. This method is suitable for a person with machinist's layout skills and with access to a substantial drill press. As an alternative to the layout method shown below it is also possible to have a machine shop properly locate the center and to mill the motor locator hole using precision mill equipment. To do this a machine shop will require an empty transmission forepiece or bell housing.

Note: this method requires manipulation of the transmission and so it should be first drained of oil. Since residual oil will drain out through the tailshaft seal the end of the transmission should be bagged.

Some of the components may require either a lathe or mill, and this work can be performed at modest expense by a machine shop. The most difficult operations to do without a lathe are the fabrication of uniform and accurate spacer blocks and the boring of the motor locator hole. Most of the remaining tasks can be done with a drill press and a bandsaw or sabre saw, often obtainable at low cost as used equipment. If a used drill press is to be used the condition of the quill bearing will be critical to the accuracy of the machine, and so also to the accuracy of the resulting adapter plate.

The exact design will be determined by the specific bolt patterns of the motor and transmission and the distance between the motor and transmission. This latter distance will typically be in the range of 75 to 100 mm.

The design described below uses three plates that are spaced by simple cylindrical spacers cut from one inch (25mm) round stock. These must have parallel faces and perpendicular holes some of which carry the alignment dowels while others carry simple bolts.

Three aluminum plates are used. The material should be a high strength alloy such as 6061.
 * Motor locator plate - this has a locating hole (typically about 100 mm) or so diameter and 4 mounting holes for bolts that fit into threaded holes in the motor body. A 5mm thickness is appropriate for this plate as it is not highly stressed.
 * Transfer plate - this is between the motor plate and the transmission plate and has bolt patterns of both the motor plate and the transmission plate. It should be sufficiently thick to not flex under stresses between the motor and transmission, with 6mm being appropriate and this must be made from a good alloy.
 * Transmission locator plate - this has the bolt pattern drilled that matches the transmission. This should be about 2.5 mm thick for stability under milling or drilling operations, and if milled (and thin) should be clamped below the transfer plate, If made from stock that is too thick then the locator dowels will not protrude enough on each side to locate the transmission and the corresponding spacer.

These plates are separated by aluminum spacer blocks milled or cut to a precise dimension from a billet of square or rectangular solid stock. Alternatively. the sides of the adapter may built up from strips of plate but this will be more difficult to fabricate to high precision unless a "sandwich" of multiple cut-out plates is used - a process that can consume a great amount of material while producing a large amount of scrap.

The motor in an ICE vehicle is typically kept in precise alignment with the transmission by two hollow dowel pins through which two of the mounting bolts are passed. These are usually press fitted into the motor block. It is the accurate locations of these dowel pins and the motor locator hole that are critical to the accuracy of the motor adapter plate. New hollow dowel pins (a set of four, rather than the two usually used in the ICE vehicle) are obtained from the parts department of the automobile dealer and are used to ensure precision alignment, both when drilling the matching pieces and when the components are assembled to the transmission.

Only the turning and boring of the cylindrical spacers and the fly-cutting or CNC milling of the motor mounting hole need be done using professional shop services; the remaining work may be done using simple but accurate machinist layout methods and a substantial drill press. Only the brave, cautious, patient, skillful and otherwise unemployed should consider making the motor hole to conform to an accurately scribed line using basic hand tools (this is possible, but not practical for most people).

This fabrication requires the ability to accurately lay out and drill various holes. This layout is done by coating the portion to be marked with machinist's blue, which is then scribed with a pointed tool. (If no machinist's blue is available, candle smoke or whiteboard pen may be used if the resultant powder is "fixed" with a light lacquer such as common hair spray. The principle layout tools required are a good quality straightedge, a scribe, a divider, and either a large divider or a trammel scribe (a bar with a fixed pivot point and an adjustable scribe. These tools need not be purchased as they may be made by the constructor. They do not require accuracy, but rather rigidity, adjustability, and the ability to hold a setting. A good machinist's scale can be useful but is not required.

There are only a few critical points of layout and cutting and drilling. These are the relative distance between the dowel pin receivers and the position relative to these of the central point. This central point must be aligned with the design center of the transmission drive shaft. This shaft is an extension of the transmission mainshaft that mounts about half of the gears within the transmission. The forward extension of this shaft carries the clutch drive splines and also has a small cylindrical protrusion called the pilot shaft that normally fits into a bearing carried in a receiver hole in the ICE crankshaft.

It is often the case that with a used transmission that the transmission drive shaft will have some play or wobble due to bearing wear, which is a good reason to replace this bearing or to have it replaced if it is practical to do so, along with the front bearing seal which should always be replaced when the transmission is out of the vehicle. Note that much of the noise produced by an electric vehicle conversion will come from this front transmission bearing and the transmission gears. A newly rebuilt transmission is recommended to obtain a quiet installation.

It will be best if the three critical points are laid out using the manufacture's design dimensions. If these cannot be obtained then the following procedure may be used:

First the approximate location of the three critical points are determined. The location of these relative to the stock used to make the plate is not critical, but the locations should allow the transmission plate to have some extra material on all sides of the transmission face.

An approximate location for a clearance hole for the transmission drive shaft may be determined by simple measurement from the dowel pin holes. Using a simple hole saw a clearance hole for the shaft is made, but only in the plate marked for the transmission. If the pilot shaft extends beyond the transmission face this hole will allow the pilot shaft to protrude when the transmission plate is against the transmission face. If the pilot shaft does not extend beyond the transmission face this will allow the pilot shaft to be viewed through the hole. Determine an appropriate orientation for the plate, center the pilot shaft in the hole, and securely clamp the plate to the transmission with some C clamps.

Place some scrap wood pieces on a bench (if required for clearance of the protruding pilot shaft) and place the transmission with the clamped plate tailshaft up on on the bench. Using some spray machinist's bluing, lightly spray into the holes that carry the dowels. This is now an approximate marking for these holes. After the bluing dries, unclamp the transmission and set it aside. If you have not got a reasonable impression of the location of the dowel pin holes, clean the workpiece and repeat the procedure.

Scribe a line joining and crossing the centers of the two dowel pin locations scribe a perpendicular line across the center of one of one of the holes. Centerpunch this location.

The next scribe and punch mark establish a critical dimension requiring high accuracy. If not done accurately the transmission will not fit properly on the dowel pins that are to go into the holes determined by this mark. Place the dowel pins into the transmission. These pins will usually be beveled on their rim. Determine an appropriate reference place to measure on the pins Place a machinist's scale across the pins and determine the extreme distance D1 between the outer edges of the pins and the smaller distance D2 between the pins. Be sure to use the same concentric reference line relative to the pin - these may be the extreme measurements on the inside hole of the pin for example. The average of these measurements (D1 + D2)/2 is the distance between the centers of the dowel pin holes. Transfer this measurement to the workpiece and scribe the location of the second hole. Do not centerpunch at this time.

Place the two workpieces together, with the transmission side of the transmission plate upward. Clamp at several places. With the drill press drill a pilot hole for one of the holes through both workpieces. Redrill with the proper size for a press fit of the dowel pin. Mark the outside of the second workpiece (the surface facing down) as "motor side". Unclamp and separate the pieces. Carefully press the dowel into the "transmission side" workpiece from the transmission side, allowing it to protrude through both sides. Placing this on the bench with the spacers you may now place the transmission on the plate with the dowel mating and the pilot shaft through the hole. You may then pivot the transmission on the plate to bring the second punch mark main scribe line to the center of the second dowel pin hole. The intersection of the scribe marks should be in the exact center of this hole. If not, rescribe as necessary and recheck. Now centerpunch the second hole. Clamp the work pieces with inside faces together, being sure that the dowel pin is engaged in both pieces. Pilot and finish drill for the second dowel and insert as with the first. The joined workpieces should now mount cleanly on the transmission using the dowel pins. If not, consider re-doing the second hole with a 90 degree re-orientation of the workpiece.

Next: Laying out the center.

Blue an area along the center of the transmission plate face from edge to edge on both sides and around the pilot shaft hole on the inside face. Erect a perpendicular to the base line joining the dowel pin holes. This may be done from reference punch marks offset the same distance from each dowel pin on the base line. Strike several sets of arcs with the trammel or a large divider. Join the intersections of these pairs with a scribed line. Transfer this scribed line to the inside face of the transmission face. Alterntatively, you could drill a small (1.6 mm or smaller) hole at each of the two punch marks and scribe only on the inside face.

The goal is to find the center for the large motor locator hole on the motor side workpiece. This will be done indirectly by layout from the inside face of the transmission plate. To do this most easily prepare a fixture to hold the transmission vertically, or place it into a large box with blocking. (The transmission should first be drained of oil.) Spray or brush machinist's blue around pilot shaft hole on the inside face of the transmission plate. Place the transmission plate, inside face up, on the transmission, aligning with the dowel pins. You should observe that the pilot pin center lies very close to the scribed centerline. As previously noted, there will be some wobble in the transmission drive shaft, so in the following it is important that the shaft is biased consistently for each scribe by applying the same pressure in each of several appropriate directions. Note that the front oil seal (especially since it is new) may apply a spring force before the bearing limit is obtained. We want to be working against the bearing limit, and so must first override any seal force. The end of the pilot shaft will have a small conical center hole, used to align the shaft as it was initially cut on a lathe when it was manufactured and when the splines were milled or broached. This center hole will form the reference for one leg of the dividers used to make the scribe marks. Now it may be that the point of the divider may be pushed or pulled to one side or the other of this hole. As with the wobble, it is important that all scribes be made consistently by pulling the scribe to the side of the hole toward which the pilot shaft is pulled. We will assume here that this is in the direction of the scribe line.

Set the dividers to a fixed distance of a few centimeters.

Pressing the pilot shaft, and puling the dividers, strike an arc at each of the cardinal directions - up, down, left, and right All scribe marks must use the same setting of the dividers. Remove the workpiece from the transmission. Lightly punch the intersection of the up and down arcs with the center line.

Blue the motor face of the motor mount plate at the center and let dry.

Now we will establish the center point on the motor mount plate. This will be done with the plate order reversed but not flipping the plates. The normal order would be to have the transmission face of the transmission plate down, the motor face of the motor plate up. Orienting the plates this way with the dowel pin holes aligned, shuffle the plates, aligning on the dowel pins and secure the plates with clamps. What is now seen is the inside face of the transmission plate its centerline and the pilot shaft scribe marks made in the preceding steps. Through the central pilot shaft hole is seen the unmarked center of the motor plate, recently blued. Set the dividers a bit longer than was used to scribe from the pilot shaft but not so much as to prevent the following scribing. From each of the light punch marks on the transmission plate scribe and arc on the motor plate through the hole. Separate the plates and mark a straight line across the intersections of the arcs. Reassemble and extend this line across the transmission plate to where it intercepts the left and right pilot shaft arcs. Lightly punch the intersection of these arcs with the line and from these punch marks scribe a pair of arcs onto he motor plate. Disassemble and join these arc intersections with a straight line. The intersection of the two lines is the desired motor center. Centerpunch this location. Quality check: The motor center location should be consistently centered on the centerline scribe marks of the transmission plate when that plate is flipped, provided the transmission line center points are accurate.

This will form the center point for a flycutter or a simple CNC milling operation. You may want to have this work done at a machine shop. The other work that you may want to have done at a machine shop is lathe cutting of the spacer blocks.

Before cutting the motor hole, layout the bolt pattern for the attachment bolts. A typical motor will use four such bolts. The holes for the bolts may be of lesser precision that that for the main motor hole but should not bind against the bolts. The bolt pattern must be aligned properly so that the motor cabling is presentable in the proper orientation. Typically a square pattern (relative to up) is used, not a diamond pattern. With this layout complete you may drill the mounting holes or this may be postponed until after the major hole is machined.

The motor mount hole must be cut to a precise diameter to fit the alignment boss on the motor. If it comes out undersize it will be necessary to enlarge it while retaining its accurate positioning, which can be difficult. If it comes out oversize this may be corrected by appropriate precision shims which are a nuisance to maintain in position. Obviously it is far better to get it right the first time.

Before cutting the center motor hole, it is now appropriate to drill the remaining transmission mount holes in both plates. Be sure to mate the two plates in the proper orientation, to each other. You may want to mount the plates to the transmission, bolting at the dowel pins and clamping elsewhere. You may then scribe inside the holes or use a cut and sharpened shoulder bolt, twirled to make a small circle. Removing the plates, clamp them together and through pilot drill and finish drill with the drill press. Remount and check clearance by inserting shoulder bolts in every hole.

Upon completion of the motor hole this may be used to scribe a hole mark on the transmission plate. This may then be rough cut on the outside of the line using a sabre saw. The purpose of this hole is for clearance around the coupling. You may want to make this hole substantially larger as it will facilitate access to the motor attachment bolts. The outline of the transmission face may be marked on the appropriate side of the transmission plate and the excess metal removed, largely for appearance. This removal may be required in only a few specific locations. A similar removal may be performed on the motor side plate

(More detailed procedure is to be provided here)

For this type of adapter plate there will be open space between the stand-offs. To keep gravel, water, and mud from the clutch this area is closed off by selecting plastic buckets of appropriate size and cutting rings to fit in between the plates.

Upon completion of the face plates and the spacer billets the bluing may be cleaned off and the plates assembled to the transmission using bolts. A thin adhesive such as cyanoacrilate (CA, or "super glue") may be flowed between the spacers and the face plates to hold everything in place (do not glue the transmission to the adapter). When the bolts are removed the entire adapter will hold together in one piece - a convenience when assembling the motor-adapter-transmission unit.

If the motor with the coupler mounted may now be mated to the adapter plate. Then the flywheel and clutch assembly is attached to the adapter. If the clutch plate has been out of the assembly it must be aligned using a pilot shaft tool to alight the plate when the pressure plate is bolted to the flywheel. This is required so that the pilot shaft and splines will properly engage the clutch center splnes when the transmission is inserted. The transmission may now be mounted - it may be necessary still to slightly rotate the flywheel to obtain engagement of the clutch splines. The transmission may now be bolted up against the adapter using bolts of appropriate length plane washers and lock washers on both sides.

After mounting the transmission, do not forget to replace the oil!

The coupling and pilot bearing
The coupling transmits the motor torque to the flywheel or to the automatic transmission flex plate. This must be strong and accurate and is almost always purchased complete or made by a professional machinist rather than fabricated by the builder. Most couplings do not provide a pilot shaft bearing since this is usually incorporated into the flywheel. While some clutchless adapters have been designed without a transmission pilot shaft bearing, this bearing is critical to long transmission life and should always be included, either as part of the coupling or as an adapter that is part of the coupling assembly.

The pilot bearing in an ICE vehicle is usually a needle bearing, as this must take many turns as the engine idles. In the electric conversion, this bearing may be made of lubricated brass or bronze, since there is far less relative motion between the flywheel and the transmission input shaft.

The flywheel
For vehicles using a manual transmission, the motor drives a flywheel, a large disk. For the electric vehicle conversion the flywheel is needed only to mount the clutch, if a clutch is used at all. The outer rim of this disk will have a gear ring shrunk or welded on, intended to be driven by the starter gear. The after face of the flywheel mounts the clutch and forms one face of the two surfaces driving the clutch disk. The flywheel will have substantial weight to allow the ICE motor to idle smoothly at low speed. Rarely, this flywheel may have been balanced as a unit with the crankshaft, in which case it may be considerably out of balance for this new application. The extra weight required for ICE smoothness reduces acceleration and the energy to spin it cannot be easily recovered, adding to brake wear. For these reasons it is appropriate to lighten and balance the flywheel, which is done with specialized tools at an automotive machine shop. This may be lighted considerably more than is the case for ICE performance enhancement. Further, the starter ring is no longer used so it may be removed for a further weight saving except where this contributes to flywheel strength. Do not remove so much material that the flywheel becomes weak. Weight removed at the periphery will be more effective in enhancing performance and will also reduce loading on the inner portion, which may be made correspondingly light. If the outer portion that contains the treads for the pressure plate mounting screws is thinned excessively it will be necessary to use nuts to secure the bolts that hold the pressure plate to the flywheel. In this case it must be possible to access these nuts in some way in order to complete the assembly of the components. An appropriate access port in the forward face of the central transfer plate should be provided, or an access from the side via a penetration of the cylindrical dust shrouds.

The clutch
Some electric vehicles do not use clutches with their manual transmissions. Such installations offer greater acceleration, lacking the rotational inertia of the clutch disk, pressure plate, and the flywheel mounting the pressure plate. Such systems require accurate shifting to avoid damage to the transmission and are not recommended for a casual use vehicle.

The clutch should have sufficient closing spring force to avoid slippage in normal operation. It should be practical in most cases to use a stock clutch and springs. Other considerations apply to a high performance vehicle for racing, some employing triple copper plate racing clutches.

Using an automatic transmission
An unmodified transmission is usually not recommended for an EV conversion owing to the inefficiencies and rotational mass associated with the torque converter and a missmatch between the normal operating speeds of an ICE engine and the replacement electric motor. Furthermore, automatic transmissions typically depend on the engine's idling rotation to maintain the transmission in a ready state. Older automatic transmissions will use a considerable amount of energy to operate the transmission's oil pump. This pump produces pressure to operate hydraulic pistons that engage the clutch bands around the planetary gearsets. Some automatic transmissions have been converted by using a properly machined splined spool to replace the torque converter, in effect forming a permanent converter lock-up condition. A particular advantage to using an automatic transmission is the presence of a parking pawl, which prevents vehicle motion when the vehicle is not operating, as a supplement to the parking brake. Shifting should be performed manually at reduced throttle since there is no longer the cushioning effect of the torque converter.

The motor mount
The motor must be securely fastened to the frame. Depending upon the original mounting configuration it may be possible to use or adapt the existing mount supports to the motor support band. It is not necessary to use the highly flexible mountings that were used with the ICE as the electric motor does not produce the periodic vibrations prevalent in an ICE. On the other hand, hard mounting a DC motor can transmit transmission noises to the frame which may be effectively absorbed by a softer mounting. Note that the transmission can produce high twisting forces and so some portion of the motor-transmission unit must be secured against rotation. This may require a separate torque arm or a mounting using extensions on the adapter plate.

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/

title: Electric Vehicle Conversion/Powertrain


text:
Electric Vehicle Conversion/Battery disposition, security, and wiring

Note the presence of hazardous materials and conditions that must be approached with proper precautions and procedures to avoid damaging, injurious, or even fatal consequences.

Separate from passenger compartment
It is considered highly desirable to separate the traction batteries completely from the passenger compartment. As the batteries form a substantial portion of the vehicle weight it is very desirable to place the batteries as low as possible in the vehicle as this enhances stability, greatly reducing the probability of rollover. Owing to the bulk of the batteries and particularly their height, this placement can be quite inconvenient in most vehicles. This is why light trucks are strongly preferred as conversion vehicles as they can offer substantial volume around the frame rails without adversely reducing ground clearance.

Protected from road hazards
For any vehicle the protection of the batteries from road contact or road debris must be carefully considered. While it is good to place the weight as low as possible the batteries should not be directly exposed to road hazards. The cases on modern batteries are relatively thin and if the plates of a cell are damaged they can overheat from the short circuit. The internal contents of most batteries are also hazardous.

Note that more than just the bottoms and sides of the batteries should be protected, since if it is possible for a conductive piece of road trash to be flipped to the terminal part of the batteries this could create a shock hazard or a short circuit and possibly a fire.

Battery security
The batteries must be well-secured to the vehicle. This is very important, since a loose battery might cause contact between the terminals and some part of the vehicle, causing a dangerous short circuit and potentially a fire or battery explosion. A pull-up security factor of 4g0 is recommended; that is, the battery mounts should withstand negative forces of four times the battery weight, for security in case the vehicle rolls over in an accident.

Battery access
The batteries must be accessible for testing, cleaning, replacement, tightening of connections, and periodic service where this is required (such as the addition of water to wet cells).

Weight distribution
Battery location is one of the most important factors determining vehicle functionality and safety. If the batteries are placed low in the vehicle it will have less tendency to tip and rollover. If too much weight is distributed to the front the vehicle will be hard to steer without power steering and the vehicle will be somewhat unresponsive. If too far to the rear the vehicle may be unstable in hard turns, tending to "swap ends", although for specialty performance cars (such as are used in autocross racing) this "oversteer" may be an advantage when controlled by a well trained and experienced driver.

Moment of inertia
For purpose-built vehicles and some electric truck conversions, it is advantageous for handling to concentrate the battery mass near the center of the vehicle. This may be done by placing the batteries in a tray between the frame rails, in a center console, or in a "saddlebag" configuration on each side of the passenger compartment. In a custom built vehicle a center console may also contain batteries.

For conversions of most common passenger and sports cars there is insufficient centrally located volume for batteries. As it is considered undesirable to place batteries within the passenger compartment this will usually lead to a "dog bone" configuration. Batteries will be placed both in the front compartment and a rear compartment (the latter created sometimes by raising the floor of the trunk, using the location of the original gas tank. This configuration can be particularly effective in earlier Volkswagen models such as the original "beetle" and the type 3, since separate compartments are built into the vehicle for luggage storage (in the front) and the motor and its cooling fan (in the rear). Owing to the distribution of mass the vehicle will have a high polar moment of inertia. This will assist it to track well on straight line highways but will reduce its nimbleness in other road conditions.

Height of center of mass
It is highly desirable to place the batteries low in the vehicle while protecting them from road hazards.

If a light truck is converted the batteries should be between the frame rails or in a dropped battery box setting atop the rails at their low point (not at the "kick up" over the rear axle) but with their bottoms below bed level. This is especially important if a truck with taller ride height is used. Most light trucks are available in a two wheel drive version that will sit fairly low and sometimes these are available in long frame models (such as the Mazda B-2000 "Sundowner"). Other examples include trucks from Mazda, Nissan, Toyota, Ford Courier (a re-badged Mazda), the Chevrolet S-10, and the GMC S-15. In long frame light trucks a long bed version, rather than a short bed—long cab is preferred unless extensive cab modifications are to be made for isolated battery placement. Note that it is important that the batteries be protected from road hazards and that the exposed connections at the tops of the batteries are not exposed to trash flipped up from road level.

Many light truck converters install a hydraulic bed lift - intended to convert the pickup into a light dump truck. This allows easy access to battery boxes below the bed.
 * Caution: If such a system is installed this must include a positive mechanical up lock, so that the batteries may be safely accessed without relying on the hydraulic system to keep the bed up.


text:
Electric Vehicle Conversion/Auxiliary systems and control

Note the presence of hazardous materials and conditions that must be approached with proper precautions and procedures to avoid damaging, injurious, or even fatal consequences.

Vehicle service electrical system
The twelve volt system is maintained to operate the headlights and various running lights, instruments, radio, heater fan, and other components common to the ICE vehicle. This low voltage is also used to control both low and high voltage relays required by the EV conversion.

Using an auxiliary battery
A much smaller battery may be used as it is not necessary to crank an ICE to start it, so the large battery may be replaced with a motorcycle, garden tractor or similar battery with much less weight and capacity of that which came with the car. The additional space may be used for an EV component such as a power brake booster pump or the 12 volt converter that keeps this battery charged. The addition of a 12 volt battery of modest size greatly simplifies satisfying the basic electrical requirements of the vehicle and allows a relatively small capacity DC-DC converter to be used, since this need not supply peak current requirements. The battery should be large enough to provide several hours of emergency flasher or parking light use, a requirement that may be beyond the capabilities of a motorcycle battery. A typical installation will only charge the battery through the DC-DC converter when the vehicle is in operation. If the usage pattern for the vehicle includes long times at rest with automatic (timed) recharge you may find it desirable to activate the converter during the charge cycles. A system that is float charged for long periods could include a separate 12 volt float charge device, sold for use with vehicles that are infrequently driven.

Some means of operating the converter to recharge a dead auxiliary battery may be provided using a separate push-button for emergency bypass of the converter relays. The converter will then provide enough power to close the relays, even while the battery is being charged. As these are usually 12 volt relays, an EV with a dead service battery will be immobile since no voltage will be available to pull in the relays - even though the traction pack is fully charged. A conventional "jump start" from another vehicle will solve the problem. (It is possible to work around the situation using some wires, clamps, and a small portion of the traction pack, but that can be dangerous and/or damaging if not very carefully performed.)

Without an auxiliary battery
Some builders eliminate the auxiliary battery, using only a DC-DC converter to produce the required 12 volt output. For a vehicle intended for street and highway operation this will require a high capacity converter. This method has the advantage of eliminating the weight of the auxiliary battery.
 * This requires the use of some relays operating at the pack voltage.
 * The DC-DC converter must produce enough power to operate all electrical loads - the headlights, turn signals, horn, emergency flashers, heater fan, radio, and any other loads such as a spotlight - simultaneously and without failure.
 * Power must also be provided for parking lights, turn signals, and emergency flashers without the presence of the ignition key in case the vehicle must be left alongside the road for some reason. An auxiliary switch may be provided for this emergency function but this must not be left on in normal use, so an associated warning light should be included in the installation.

Power steering
If power steering is incorporated this is often done by driving a conventional pump with an additional small motor. The power steering pump may be driven directly from the traction motor, as can the air conditioning. Since the traction motor is stopped when the accelerator pedal is not depressed (unlike an ICE which "idles") special techniques will be necessary to drive the power steering when parking. Due to the complexity and inefficiencies power steering is not usually included in a conversion if the vehicle is suitably light. Note that if the original vehicle is equipped with power steering then it should be powered owing to fact that the ratios used in power steering units will lead to rather high wheel forces when the device is not powered. For this reason, vehicles with manual (unpowered) steering units are preferred. Some recent production ICE (e .g. late models of the Saturn) and particularly hybrid vehicles use electric powered steering, a solution well suited for an EV conversion, but not readily available as of 2005.

Air conditioning
While production electric and hybrid vehicles have been provided with electric air conditioners this modern equipment is not generally available in a converted vehicle. Some versions of propulsion motors include a front end shaft that may be used as an accessory drive, and vehicles have been converted to use the existing air conditioning pump. An alternative is to drive the pump with an auxiliary motor as described for power steering above.

Heater
The typical ICE heater uses waste heat from the engine cooling system. The fluid circulated through the heater may be warmed by an electric resistance heater and circulated with an auxiliary pump. It is more usual in a conversion to provide heat by replacing the water radiator (heater core) with a ceramic resistance heater. The parts and materials for this conversion are available from EV conversion suppliers although for a reasonable range of pack voltages (96 to 120 volts) a common ceramic core space heater may be adapted. As this will likely require bringing pack voltage into the passenger cab the installation must be done with care to avoid creating a fire or shock hazard. A heavy duty relay is required for power control and is typically actuated by both fan operation and an intermediate or higher heat control setting. Thermostatic control is seldom included but would be appropriate for colder climates.

Radio
Radios are sensitive to electrical noise from the motor controller and the service voltage (12 volt) power converter. This noise can come through the receiver as radio frequency interference (RFI) or through the power supply as noise on the 12 volt system. A satisfactory radio installation is one of the most difficult conversion tasks to complete.


text:
Electric Vehicle Conversion/Chassies, suspension, and running gear

Note the presence of hazardous materials and conditions that must be approached with proper precautions and procedures to avoid damaging, injurious, or even fatal consequences.

Unit body rust
Rust problems in a vehicle can be expensive and difficult to correct. Recent vehicles have been substantially improved in their corrosion resistance, using zinc plated metal and full dip priming. Older vehicles do not have this quality of build and may be subject to rust. This is especially important in unit body construction, where thin sheet metal provides the primary structure of the vehicle. This is another reason to convert a light truck - almost all are built with a sturdy frame to which the battery load may be transferred.

Tires and wheels
A selection of wheel and tire combination must respect both the weight and intended use of the vehicle and its expected loads. A low rolling resistance is desirable, obtained usually by choosing an appropriate belted radial passenger car tire. For light trucks this means using a tire intended for a rather heavy sedan, rather than one designed for a light truck, assuming that the vehicle is intended to be used on improved roads. For a light vehicle it will be necessary to use wheels and tires suitable for this weight, which may not be available as standard equipment, and suitable tires may not fit the wheels that are on the vehicle. As more popular vehicles will have a wider choice of aftermarket wheels and tires this might influence the choice of vehicle to convert.

The converter should resist the urge to add a wide stance to the vehicle by selecting a wheel with a greater rim offset. As with ICE vehicles this added offset can upset the carefully designed steering geometry and imposes additional stress on spindles and axles. On top of this, the conversion will carry weight near the maximum vehicle capacity at all times, imposing additional stress on the suspension components.

Suspension
The additional weight of the batteries will cause compression of the springs which in most vehicles will change the suspension geometry. This will also reduce the space available for suspension travel. Such compression might be rarely encountered in an ICE vehicle as it corresponds to the maximum load. In an electric vehicle this load will be present at all times, so the suspension travel and geometry should be restored by various modifications.

Ground clearance
It may be desired to restore normal ground clearance, especially important if the batteries are between the frame rails of a truck or similar vehicle. Under other circumstances such as the creation of a sports electric vehicle a low ground clearance may be desirable as it can reduce aerodynamic drag and reduce rollover tendencies. A low ground clearance may also be considered as a styling element.

Spring rate and spring force
Spring force is the amount of force applied by the spring at is normally loaded condition. If weight is added to the vehicle the springs will compress until the necessary force is obtained or the suspension "bottoms out", by resting on the "snubber pads" that prevent metal–to–metal contact at full travel.

Spring rate is the additional force applied by the spring for each unit measure of spring compression. Additional spring rate is used to prevent excess compression of the suspension due to road bumps and to reduce the tendency of the vehicle to lean in turns. Additional spring rate is especially important if the suspension travel is reduced as part of the vehicle's styling and handling modifications.

Additional spring force may be obtained by several means:
 * Air adjustable shock absorbers.
 * Coil spring over shocks. ("coilover shocks")
 * Stronger coil springs.
 * Air bladder within coil springs. These are adjustable with air pressure but require that the shock absorber is mounted outside of the coil.
 * Additional leaf in leaf springs. This is a common modification to truck suspensions.
 * Coil spring shims. This does not increase spring rate as do the methods above. Note that full suspension travel plus bump pad compression must be available, so this may not be a practical solution)

Shock absorber damping rate
When the spring rate is increased then the damping rate applied by the shock absorbers should also be increased. If the suspension modifications are by use of coil-over or air adjustable shocks then the appropriate damping may be obtained by proper equipment selection. Some high end shock absorbers allow the damping rate to be adjusted statically (by mechanical adjustments on the shock absorber).

Integrated struts
McPherson struts are commonly used in the front suspensions of lower priced modern sedans and coupes. These struts use a robust coil–over shock absorber to perform four functions:

 * To maintain suspension geometry by controlling camber and caster by its relationship to a single lower A–arm
 * To provide suspension travel
 * To provide suspension damping
 * To allow steering motion of the front wheels

In some suspensions the coil spring is separate from the strut and bears on the lower A–arm.

A similar device, the Chapman strut is used in the rear of some sports cars (such as the Fiat X1/9). The ability to obtain specialty racing equipment replacements for these struts should be considered when selecting a light car for conversion. Only a limited number of performance vehicles will have high rate or adjustable struts available. Where such components are available it will likely be possible to also obtain high performance brake components.

Brake capacity
Since the vehicle should never be driven if the total vehicle/passenger/cargo weight is above the manufacturer's GVWR, it might be considered that is no need for brake upgrades. Without energy recovery or dynamic braking there is not the retarding force of engine compression, so greater brake wear is to be expected, and brake overheating on a long downgrade is a possibility. For this reason higher performance brakes are preferred in an EV conversion, specifically the use of disk brakes at the front of the vehicle.

Vacuum brake boost system
With the heavy additional weight associated with the batteries it is important that heavier vehicles be equipped with power brakes. As these are (typically) operated by engine intake manifold vacuum a conversion will require a vacuum pump and a chamber to act as a reservoir. Additional control circuitry with vacuum switch(s) and relay(s) to regulate the pump motor is also required and is documented in another section of this book. Pumps may be obtained for EV use from specialty suppliers and some older production ICE vehicles used factory installed pumps.

For a list of production ICE vehicles with vacuum pumps see this site.


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Handbook of Genetic Counseling/Coffin-Lowry Syndrome

Coffin-Lowry Syndrome

Mode of Inheritance

 * X-linked dominant

Chromosome Location

 * Xp22.2-p22.1

Molecular Genetics

 * Coffin-Lowry gene is a growth factor regulated serine-threonine kinase (RPS6KA3 or RSK)
 * Kinase activation in a number of pathways
 * Plays a role in stimulation of the cell cycle between G0 and G1
 * Activates CREB (cAMP response element binding protein)
 * Involved in neuronal survival
 * Involved in conversion from short term to long term memory
 * Cells in patients with CLS have defective EGF stimulated phosphorylation of S6
 * There are normal variants/polymorphisms
 * Normal gene product: ribosomal protein S6 kinase alpha 3
 * Mutations in the RPS6KA3 give rise to CLS and XLMR

Penetrance

 * In males with the disease-causing mutation: 100% will be affected
 * In females with the disease-causing mutation are carriers and are at high risk for developmental delay and mild physical signs of CLS

Incidence and Carrier Frequency

 * No estimate of prevalence has been reported.
 * Estimate of A. Hunter et al., Children's Hospital Ontario: 1/40,000 to 1/50,000

Clinical Features

 * Growth Failure
 * Prenatally, growth is normal
 * Postnatal growth failure occurs early
 * Males usually fall below 3rd percentile in height
 * Microcephaly can be seen, but not in all cases
 * Dental Anomalies are common
 * Small teeth
 * Malpositioning
 * Hypodontia
 * Delayed eruption
 * Premature loss
 * Palate is high
 * Retrognathia in young children is replaced by prognathia
 * Neuropsychiatric
 * Patients are generally happy and pleasant
 * Severe MR occurs which may inhibit detailed neurologic assessment
 * Neurologic findings:
 * Loss of strength and muscle mass
 * Both decreased and increased deep tendon reflexes
 * Sleep Apnea
 * Stroke
 * Progressive spasticity
 * Progressive paraplegia with loss of the ability to walk
 * Due to calcification of the ligamenta flava
 * And Congenital stenosis of the spinal canal
 * "Drop Attacks"
 * Affect 10-20% of patients
 * Unexpected tactile or auditory stimuli/excitement trigger EMG silence in the lower limbs
 * Results in a brief collapse, but no loss of consciousness
 * Frequency of attacks may cause the need for a wheelchair to prevent injury
 * Cardiovascular
 * ~14% of males and ~5% of females have cardiovascular disease
 * Abnormalities of the mitral, tricuspid, and aortic valves
 * Short chordae
 * Cardiomyopathy
 * Congestive heart failure
 * Dilatation of the aorta and pulmonary artery
 * Cardiac anomalies may contribute to premature death
 * Musculoskeletal
 * Progressive kyphoscoliosis
 * At least 47% of affected males have this (32% of females)
 * Respiratory compromise can happen due to this
 * Hearing and Vision
 * Some patients have been reported to have hearing loss (14/89 males and 1/22 females)
 * Clustering of hearing loss in families may occur
 * Significant vision problems are uncommon
 * Cataracts, retinal pigment atrophy, and optic atrophy have been reported
 * Incidence of chronic eyelid irritation may be increased
 * Miscellaneous Findings
 * Singles cases:
 * Rectal prolapse
 * Uterine Prolapse
 * Unilateral renal agenesis
 * Pyloric stenosis
 * Jejunal diverticuli
 * Colonic diverticuli
 * Popiteal ganglion
 * Anteriorly placed anus
 * Increased facial pigment
 * Enlarged trachea

Lifespan

 * Mortality
 * Early mortality is increased in CLS
 * 13.5% of males/4.5% of females mean age of death 20.5 years
 * Complicating factors include:
 * Cardiac anomalies
 * Panacinar emphysema
 * Respiratory complications
 * Progressive Kyphoscoliosis
 * Seizure-associated aspiration

Testing

 * Ribosomal S6 kinase enzyme assay
 * Performed on cultured fibroblasts or transformed lymphoblasts
 * Available on a clinical basis in males
 * Not as useful in females due to broad range of enzyme activity resulting from X-chromosome inactivation
 * Molecular Genetic Testing
 * Uses of testing
 * Confirmatory diagnostic testing
 * Carrier testing
 * Prenatal diagnosis
 * Test Methods
 * Mutation Scanning
 * SSCP analysis (followed by squencing of abnormal exons)
 * Available on a clinical basis
 * In CLS patients, mutations were identified in 34% who had a clinical diagnosis
 * A negative study does not rule out the diagnosis of CLS
 * Protein Truncation testing
 * ~60% of 71 mutations idenitifed caused protein truncation
 * Western blot then sequencing of variants
 * Performed on cultured lymphoblasts
 * Is available clinically for affected males
 * Linkage Analysis
 * For families in which direct testing has not identified a mutation
 * Assesses probability that at-risk individuals have inherited a familial mutation
 * Acurracy dependent on:
 * Accurracy of clinical diagnosis of CLS
 * Informativeness of genetic markers in the family
 * Samples are required from multiple family members to perform analysis
 * Laboratories offering clinical testing
 * Universite Louis Pasteur
 * Institut Genet Biologie Molec/Cellulaire Illkirch, France
 * Director: Pierre Chambon
 * Contact: Andre Hanauer, PhD
 * email: Email: andre@titus.u-strasbg.fr
 * phone: (+33) 3-88-65-34-00 fax: (+33) 3-88-65-32-46
 * Methodology: Direct DNA analysis, Linkage, Enzyme Assay, Protein Analysis
 * Additional Testing Provided: Prenatal diagnosis

 * Laboratories offering research testing
 * JC Self Research Institute
 * Center for Molecular Studies Greenwood, SC
 * Director: Charles Schwartz, MS, PhD
 * Contact: Cindy Skinner, RN
 * email: cindy@ggc.org
 * phone: (800) 939-1920 phone2: (864) 941-8115 fax: (864) 388-1707
 * Description of Research: Mutational analysis using SSCP or DHPLC, is done on all exons of RSK2 in males suspected to have CLS. Contact prior to sending samples.

Surveillance, Management, Treatment

 * No specific therapy for CLS
 * Need for development of communication skills and self-care
 * Vision and hearing testing is appropriate
 * Cardiac studies should be done in childhood
 * Repeated every 5-10 years
 * Monitor for the development of progressive kyphoscoliosis
 * Intervention to prevent progression is appropriate
 * Should be suspicion for narrowing of spinal canal
 * Attention to gait
 * Bowel/bladder habits
 * Expression of pain
 * Focal neurological changes
 * Clonus
 * Abnormal tendon reflexes
 * Awareness of "drop attacks"
 * Allows early intervention to minimize occurrence of triggering stimuli
 * Trial of antiepileptic medication may be indicated
 * Significant social resources may be required to support women with CLS

Differential Diagnosis

 * Borjeson-Fossman-Lehmann Syndrome (BFLS)
 * X-linked recessive disorder
 * Severe MR
 * Hand findings
 * Short anteverted nose with thick septum
 * Small nares
 * Kyphoscoliosis
 * Facial appearances similar to CLS:
 * Williams Syndrome
 * FG syndrome
 * X-linked alpha-thalassemia MR

Resources/Support

 * NINDH Coffin-Lowry Information Page
 * http://www.ninds.nih.gov/health_and_medical/disorders/coffin_lowry.htm

 * Coffin-Lowry Syndrome Foundation
 * 3045 255th Avenue SE
 * Sammamish, WA 98075
 * CLSFoundation@yahoo.com
 * http://clsf.info
 * Tel: 425-427-0939 (M-F after 6pm PST

 * National Organization for Rare Disorders (NORD)
 * P.O. Box 1968
 * (55 Kenosia Avenue)
 * Danbury, CT 06813-1968
 * orphan@rarediseases.org
 * http://www.rarediseases.org
 * Tel: 203-744-0100 Voice Mail 800-999-NORD (6673)
 * Fax: 203-798-2291

 * National Institute of Child Health and Human Development (NICHD)
 * National Institutes of Health
 * Bldg. 31, Rm. 2A32
 * Bethesda, MD 20892-2425
 * NICHDClearinghouse@mail.nih.gov
 * http://www.nichd.nih.gov
 * Tel: 301-496-5133 800-370-2943

 * National Institute of Mental Health (NIMH)
 * 6001 Executive Blvd.
 * Rm. 8184, MSC 9663
 * Bethesda, MD 20892-9663
 * nimhinfo@nih.gov
 * http://www.nimh.nih.gov
 * Tel: 301-443-4513 TTY: 301-443-8431 Depression Info: 800-421-4211 Anxiety Info: 88-88-ANXIETY (269-4389) Panic Info: 888-64-PANIC (64-72642)
 * Fax: 301-443-4279

 * The Arc of the United States
 * 1010 Wayne Avenue
 * Suite 650
 * Silver Spring, MD 20910
 * Info@thearc.org
 * http://www.thearc.org
 * Tel: 301-565-3842
 * Fax: 301-565-3843 or -5342

 * March of Dimes Birth Defects Foundation
 * 1275 Mamaroneck Avenue
 * White Plains, NY 10605
 * askus@marchofdimes.org
 * http://www.marchofdimes.org
 * Tel: 914-428-7100 888-MODIMES (663-4637)
 * Fax: 914-428-8203

Conclusions

 * Review session
 * Answer final questions
 * Give card