This Manual is for the Converted MG Midget, It is now Electric!

Table of Contents:

Acknowledgments

1.0 Introduction

1.2 Theory of Operation

2.0 Daily Operation

2.2 EV Driving Tips

3.0 Maintenance

3.2 Things That Don't Need Doing any more

3.4 A Few New Things

4.0 Trouble Shooting

5.0 Technical Info

6.0 Appendix

6.1 List of Suppliers (EV Components)

6.2 Information Sources (References)

6.3 List of Sponsors (Thanks)

Links to other places:

Technical Stuff

Project Main Menu

Acknowledgments:

The next group of people I would like to acknowledge are all the riders, sponsors and volunteers that helped put on the Ride for the Electric Car. With out their efforts and contributions the financing of this project would have taken a lot longer.

Last and certainly not least I would like to thank all the companies, organizations and individuals that contributed to the Project; to list a few: the Electric Auto Association who donated the motor, Curtis PMC who donated the controller, Empirical Engineering for the adapter plate, Good Year for the low rolling resistance tires, GNB for a reduced price on batteries, Dave at British Motor Sports for trading in of the old engine for MG parts, Bill Young Tires for free balancing and mounting of tires, Jeff Shrager for payment of battery delivery, Margaret Hebert for T-shirt design, Clare Bell for a second set of used batteries and many more.

David Coale

Electric Vehicle                          ____o\____
Project Leader                     =)----/()______()\

1.0 Introduction

1.1 Bay Area Action and The Project

The Electric Car Project was started with the donation of an MG Midget from Will Doolittle with the stipulation that the MG be converted to run on Electric power. An outline of the project was written up and interested project members met to work on the first task at hand information gathering; the "what" and "how" of converting a car to electric.

The "what" is what do you need to do this and the "how" we had to figure out. Bob Schneevies supplied the initial parts list and said when we had all the parts and the fund raising done he would help us with the "how".

It was at this point that I got involved with the project. We started with the parts list and wrote letters to the suppliers asking for donations for our project. This served us well as we got a 20 hp Prestolite motor from the Electric Auto Association (EAA) and a controller from Curtis PMC. These were both major items on the parts list and helped to reduce the amount of fundraising to be done.

By way of looking into the "how" of it, I found out about the EAA and started attending their meetings. I also took a one day class on how to convert your gas car to electric. Another very important "how" was to get to know Bob Schneevies and other people in the local Electric Vehicle (EV) community. This lead to helping Bob with a race car he was building for the 3rd APS Solar and Electric 500; but that is another story.

I had offered to have the conversion done in my garage. This way I would learn the most about it and this suited me fine. This also turned out to be quite appropriate as project leaders came and went; pursuing jobs and academic enlightenment; and I ended up as project leader.

With the place for the conversion and the few parts that were donated wehad enough to start. Meetings would now be at my house/garage and they would be working meetings; hands on. We got the car weighed and found an MG place that would take the old motor and all the other parts we would not need in exchange for credit for parts we would need (suspension).

The first major team assembled on a Friday night and by noon the next day we had the old engine and all the other parts, radiator, exhaust system, gas tank, etc., loaded into a small pickup and ready for delivery to the MG place. From here on out the work went more slowly. Now we had to think about how to fit the electric parts into the space left by the old internal combustion parts. We also had to raise funds for the parts we did not get through donations.

We had a brunch at my house to raise money and awareness about EVs. I had contacted several EV owners to come and show their cars. Many of them gave people rides and talked about their cars. It was quite successful but we would need a lot more then the $300.00 that we were able to raise at this event. So between figuring out where to put all the EV parts we also put together a benefit bike ride to raise the rest of the money.

The bike ride turned out to be ten times better then the brunch and was also more work, but well worth it. We raised over $3,000.00 for the project! I also had a variety of EVs at this event: two electric cars, an electric go-cart, electric bicycle and even an electric wheel barrow!

Work continued on the car and was again interrupted in early spring to help Bob with the 4th APS Solar and Electric 500. Several project members helped out with this effort and went to Phoenix with Bob. It was more immediate and more exciting to work on (sexy) then the MG. After Phoenix Bob donated his old batteries to us so we could test and have a working car by Earth Day; and we did! From the Project update postings:

Subject: EV birth announcement;

Congratulations, it's an electric car! On Sunday April 10th at about 1:00 PM, a maroon MG Midget rolled out of David Coale's garage under it's own quiet, smooth, electric power. Bay Area Action's Electric Car Project gave *rebirth* to a 2100 LB, 132 volt Zero Emission Vehicle.

The last bit of *labor* started at 10:00 am with the connection and tie down of 11 12V Optima batteries. This set of used batteries from the legendary SnoWhite (good electron pool, eh?), will get the car through its teething period, until our battery sponsor (GNB) delivers a new set of 12V EVB-1180 batteries sometime in mid May.

The first test drives revealed a few minor oversights which were easily corrected. Paul Hebert, team member and electric car owner, said the MG is peppier than his own electric Sunbeam and handles reasonably well.

The range will be quit limited with the used batteries but we will be able to thoroughly check the rest of the systems on the car and show a working car at this year's Earth Day events.

Now that the car was working it was time to show it off, and we did. The Earth Day showing was a rather damp affair. For those who missed it or showed up after 12:30 (canceled due to rain) perhaps the highlight of the day was to hear Senator Tom Hayden speak. He spoke about a lot of things, but what interested me the most was his knowledge about electric cars. He owns two electric cars, one in LA and one in Sacramento. It was great to hear a politician (of all people) talking about the practical use of EVs. He knows as much as any EV advocate.

One good thing about the rain on that day: I got to test the heater in thecar (driving home in the pouring rain, no top yet) and it works Great!

Sunday the MG made another appearance at BAA's Creek clean up. Much better weather that day. The car drew quite a crowd and I missed the band that played for the clean up volunteers because I was answering questions about the car. After charging for a couple of hours David Smernoff and I made a speedy getaway as the remaining people looked on in total silence.

The next showing was at the Palo Alto Concours d'Elegance May 29th. The Concours is an antique (and other) car show that happens every year at Stanford. The MG was there as one of the "other" cars, but this time it was not alone. Paul Hebert (project member and EV owner himself) arranged for 12 other EVs to be there! We had quite a showing. Everything from a grade school solar cart to SnoWhite (electric race car) and the electric wheel barrow. Most of the EVs were of the commute type. The crowd kept the owners busy answering questions and handing out literature. Good show; thank you Paul.

We made a final push to complete the car in time for the fourth Solar Energy Expo and Rally (SEER) happening in Ukiah; excepting a few optional items like the belly-pan and installing the convertible top. The tow-bar and attachment brackets were installed, the new batteries arrived and were installed and bracketed in. The car was test driven for several cycles and was generally performing very well. The few remaining items will be completed over the next 3-4 weeks and the car will officially be in maintenance mode.

Unfortunately, the motor was damaged during the tow to SEER and needed repair or replacement. This put a damper on the project to say the least. Now we had to find a repair place and worry about financing it. This took a while.

We finally got the Motor back from being rewound and installed it only to find that the rewinding job was not too good. We heard a knocking sound and had to take the whole thing apart (again). Found out it was the armature (inside rotating part) hitting the field windings (outside electric magnets). With the help of Otmar and Bob (local EV experts) the motor was reconditioned (long story) and is now in the MG and running!

With the car in working order again we were able to take it to various events for show and tell. The "All Right Now" Parade to celebrate homecoming at Stanford and a salute to the Palo Alto Centennial turned out to be a lot of fun. Paul and I managed to get 15 EVs together for this EVent. Bob Schneeveis had six EVs to his credit there. All the EVs got a good response from the crowd. Nothing like good positive vibes to get your batteries recharged!

The new GNB batteries have not worked too well. Two of the batteries have died and the others do not have the capacity that we expected. We are working with GNB to get all the batteries replaced. One other issue is the insurance for the car. Right now it is for a single driver only. This limits our plans of lending the car to the various project team members so that each of them can show it around and use it to help establish a charging place where they work.

We are still getting around and promoting the use of EVs as a clean, quiet commute alternative. We have been featured in several articles on electric cars in the local papers and we are planing to do a video about EVs. Stay tuned.

1.2 Theory of Operation

The energy produced by a normal auto engine is stored in the long carbon molecules of gasoline. This energy is released when the gas is burned in the engine. This process is not reversible and the main, and mostly un-usable outputs of the process are heat, noise, and exhaust. In fact, ICE vehicles have complicated subsystems devoted entirely to handling these unwanted effects of combustion - the exhaust, EGR, PCV, catalytic converters, and cooling systems of the car. All of these systems require regular maintenance and/or periodic replacement.

The energy in this Electric car is stored in the batteries. When a current path is provided, a chemical reaction takes place in the batteries. This reaction produces the electricity used in the electric motor, controller, and 12 volt auxiliary systems. Under hard acceleration or when the batteries are nearly depleted, some heat is produced, but not enough to need regulating systems. The chemical reaction in the batteries is over 95% reversible, which is what happens when the battery is charged.

1.2.2 Energy Delivery

In the normal auto engine, the power is controlled by changing the volume and mixture of gasoline and air entering the combustion chambers and the timing of the ignition spark. This is done by a carburetor or a fuel injection system and the distributor and spark plugs. The carburetor/fuel injectors provide a mixed vapor of gasoline and air, which are ignited at the correct instant by the spark produced by the ignition system. These systems also require regular maintenance and periodic adjustment for maximum efficiency. The maximum energy efficiency of a modern ICE is ~20- 25%. If an ICE is running poorly, these systems are the first to be checked. During normal operation, the ICE is always running at or above ~600 RPM. If the speed falls below this the motor will stall and need to be restarted (the starter subsystem is another feature not required in an EV).

In the electric version, power control is handled by an electronic PWM controller. This has no moving parts and its only adjustments are current limit and ramp-up speed, neither of which needs adjusting after being set initially. Under normal operating conditions both the controller and the motor produce a modest amount of heat. In this vehicle the controller is cooled by an aluminum heat-sink and a small cooling fan. Some EVs also use a blower to force cool air through the motor if the motor temperature exceeds a preset limit.

The current is fed to the electric motor, which has five moving parts: the armature assembly and 4 carbon brushes. None of these require adjustment although the brushes may need to be replaced after ~60,000 miles of use. The energy efficiency of the motor controller combination is ~ 70-80%. When the vehicle is stopped, the electric motor is also stopped, and no energy is being used. The same is true whenever you take your foot off the accelerator pedal. Some EVs (not this one) have motor-controller combinations which allow them to act as a generator when braking, thus recovering some of the energy used to accelerate the car and reuse it at the next opportunity!

2.0 Daily Operation

2.1.1 Yellow Indicator

This light used to indicate an alternator problem, now it just means the car is on. Since there is not much else to tell you the accelerator pedal is live, we though it important to have a clear indicator.

2.1.2 Red Indicator

This used to indicate low oil pressure, now it indicates the car is plugged in or over temperature on the motor. When the car is plugged in, this light is on and the main contactor is disabled. If this light comes on during driving it indicates that the motor is too hot. Driving in a higher RPM range will help cool the motor. 2.1.3 Blue Indicator

This still indicates your high-beam lights are on.

2.1.4 Voltmeter

This new gauge shows the main battery pack voltage at all times. When fully charged it will register between 145 and 150 volts. It is normal for this to waver when you are accelerating. As the battery pack gets depleted it will read a lower voltage even when there is no load (foot off the pedal).

2.1.5 Ammeter

This new gauge is not the same as the ammeter's on conventional cars, which indicate whether the starting battery is charging or discharging. This one indicates the current being supplied by the main pack to the controller. It registers up to 400 amperes, but typically stays below 200 amps except on hard acceleration.

2.1.6 Ignition

The key is still used to turn the car on, but there is no need (or effect) to turn it all the way over when you start the car. When the car had a gasoline engine, turning the key all the way over ran the starter motor. If the yellow light came on, the power is on.

2.1.7 "Cutoff" switch

The emergency power cutoff is the silver plunger between the seats. Pulling it forward towards the front of the car turns it off. Pushing it back to the rear turns it on. With this switch turned off, the car won't go, nor will the batteries charge. It serves as a safety disconnect when working on the car (e.g. tightening connections) and as an emergency power cutoff should anything ever go wrong in the high voltage circuit (if you smell smoke, hear sparks, or anything else makes you nervous, just turn it off).

2.1.8 The Heater

The heat in a gas car comes from the internal combustion engine. In an EV the heat must come from some other source. The MG has an electric heater. The heater element is powered from the main battery pack while the fan is powered from the 12 volt system. This new heater is placed underneath the dash on the drivers side. The heater switch is on the left side of the dash while the vent adjustment is on the heater. The old vent adjustment to the left of the heater switch is inoperable.

2.1.9 Tachometer

The tachometer is not working at this time. Since the tach. ran off of the distributor, and there is now no distributor there is no tack. At some later point the tachometer may be made to work; but for now it will read zero.

2.2 EV Driving Tips

When you learned to drive a standard shift the key skill was slipping the clutch when starting out from a stop. If you didn't do it right the engine would stall, you would need to put the car into a neutral gear and restart the engine (very embarrassing). An electric motor cannot be "stalled" in that sense (the motor used to start the gasoline engine is a close cousin of the EV power plant). You can put the car in 1rst gear (do use the clutch when actually moving the shift lever), let the clutch out, *then* gently depress the accelerator; this is a lot like putting an automatic transmission car into gear. Some EV manufacturers have modified the controller to provide a small current at a stop to the motor so that it will "creep" like an automatic (not this car). The MG starts out without much of a jolt, and accelerates nicely. You could also have started out in 2nd gear. The only difference is that the initial acceleration (0-5 mph) is not as dramatic. (In many urban traffic situations, there is no practical benefit to starting off in 1rst.)

2.2.2 Shifting Gears

Once you're moving, shifting gears is straightforward. There is one guiding rule and one important warning. The guiding rule is that the motor is more efficient at higher RPM, so deferring shifting rather than early shifting is a good idea for efficiency' sake. The warning is: NEVER downshift an EV. There is little braking power available via downshifting and it is relatively easy to over-speed the motor this way. This can be a hard habit for standard shift driver's to break, but motor replacement/rebuilding is an expensive way to learn the lesson. Typical speed ranges for each gear follow:

	1rst gear	0-15 mph
	2nd gear	[0]15-35 mph
	3rd gear	35-65 mph
	4rth gear	60-75 mph (for passing)

Since converted electric vehicles tend to weigh more than they did originally, they often require more pressure applied to the brake pedal than their gasoline predecessor. Also, since there is no "compression" effect in an electric motor, the car does not slow down noticeably when you take your foot off the "gas".

Finally, the momentum of the motor armature/hub/flywheel/clutch assembly is contributing to the forward momentum of the car even if your foot is off the accelerator. Shifting into neutral or pressing in the clutch can help you slow down more quickly if needed. If you do this, the armature may continue to spin for a minute or more. I sometimes use this "flywheel" to help start out after a brief stop.

2.2.4 Handling

It has already been mentioned that converted EVs weigh more than their predecessor. It is also true that the weight is positioned very differently than before. Many EVs have more than half of the battery weight in the rear of the car. Some have a significant fraction of this weight behind the rear axle. This affects the way the car handles when cornering. Even though the EV will tend to lean less when cornering, it will often sway from side to side more.

Also, the extra weight in the rear end is slower to bounce back from a bump or a pothole. It is wise to take rough roads or speed bumps nice and easy in an EV - especially a low slung one like this MG.

Most EVs (this one included) also use low-rolling resistance tires to increase the range of the car. These tires trade off some ride comfort and traction for greater efficiency. Again, under normal conditions you won't notice the trade, but on wet or slippery roads, the harder tires combined with the rear battery pack can cause the rear tires to slip sideways when you turn a corner (like on a freeway ramp) at moderate speeds or trying to accelerate. Being aware of this is sufficient to prevent a mishap.

2.2.5 Maximum Range vs. Nominal Range

Given that the comparatively low range of EVs is their most cited drawback, this next item is a bit of bad news. Although the deep- cycle batteries used in EVs can tolerate being deeply discharged many times, frequently driving the car close to the range limit will reduce the overall life of the batteries. As a general rule, it is wise not to drive more than half the maximum range before some charging is done. If you normally discharge the battery more than 50% then the cycle life of the battery pack can be reduced by half (instead of lasting 3-5 years the pack will need replacing in less than 2). Several studies have indicated that most people drive less than 30- 50 miles a day on average. Since most EV conversions get between 40-60 miles on a charge, it should be easy to meet the goal of keeping cycles reasonably shallow.

2.2.6 Opportunity Charging

If possible, practical, and politically correct ;-), find out if people at intermediate destinations mind if you plug into a convenient outdoor outlet while you are there. Even 15-20 minutes of charging can make a surprising difference to your battery pack. This has been dubbed "opportunity charging". If you regularly shop at a specific supermarket or shopping center, find out if they have outdoor outlets and would allow such charging. Many companies are supportive of employees who drive an EV to work and will allow you to charge up during the work day. Generally, the cost of the electricity is less than what it would cost them to bill you for it, and in some counties and states, employers receive special consideration or incentives to provide such infrastructure. My rule is, don't be shy *and* don't be a pest.

2.2.7 Conservation of Energy

The range of your EV is a function of your driving habits. The batteries are designed to provide the best range at a steady current of about 75 amps. During accelerating the current quickly climbs to 200-300 amps and beyond. Although the batteries can easily produce this power level for short periods, they cannot sustain it for long. For a short time after a high current push, the battery is chemically imbalanced. Given a brief rest, this imbalance is self correcting. That is why it's possible to drive on a short while after "running out of juice".

All of the tips that follow are the same as for gas cars in terms of increasing mileage and ultimately boil down to treating the batteries as gently as possible. #1 Accelerate moderately - try to keep it under 150 amps, 100 would be even better. #2 Coast whenever you can, down hills, approaching a traffic signal. Anticipate lights changing. #3 Follow at a distance of 2-3 car lengths at least - just like they teach us all when we get our licenses. That way you won't have to slow down every time the car in front of you does or speed up immediately after that. #4 Learn and use EV 'friendly' routes. These are roads with relatively few stop signs/lights and normal speeds in the 35-40 mph range with few hills. If lights are timed, learn how to pace yourself through them. Often times these routes take only a few minutes longer than the highway. 2.2.8 Where's the Fuel Gauge?

Some folks use the voltmeter as a fuel gauge. As the voltage at rest drops, you can be sure you're getting low - but how low can be tricky to estimate. The best indication is a combination of voltage and current. One handy trick is to maintain a 50 or 100 amp current and check the voltage at that time. Make notes when stopped about how many miles into the cycle you are and what the 50-amp voltage is. After a short while you will be able to make a small table that lets you know the condition of the batteries using such a check.

A more mundane, and perhaps user friendly method is to zero the trip mileage counter after every full charge. Comparing the cycle miles to the known range of the car, you can easily assess your fuel status. This will vary some what with the terrain and type of driving (freeway/hard acceleration or constant 35-40mph).

These two strike me as the most practical. Some EVs are equipped with more sophisticated indicators - watt-hour meters and such. These are better than the simple current and voltage method - but I'd still take the precaution of tracking the miles driven each cycle as back up indicator.

2.2.9 Running Out of Juice

If you drive an electric car, sooner or later you will run out of "juice" short of your destination. Most often this is because of human error - a circuit breaker tripped and you didn't realize the car didn't charge last night, or someone used it and thought they'd charged it but it wasn't completely charged. Sometimes there may be a problem with one battery or another that impedes charging. For whatever reason, it is likely to happen.

When it does, it usually happens quickly; one minute everything is running fine, and the next you are losing power and slowing down. This is especially true if you are driving on the highway, where it takes significantly more than 75 amps continuous power to maintain highway speeds. As quickly and can safely be done, find a place to pull over and stop. If there is not any place obvious nearby, slow down to 30-35 mph, turn on flashers, and maintain that speed as well as you can to nurse the car to a safe stopping place. If this enables you to get to a familiar location, a gas station (how ironic) or a residential neighborhood, so much the better.

By letting the car sit for 15-20 minutes, you are giving the batteries a chance to equalize their chemistry and recover some. Of course, if you are bold enough and stopped someplace where they may help, go on and ask if you can plug in. Depending on many things (pack size, terrain, need for lights or other accessories), after resting for a short spell you can probably go another 2-5 miles if you accelerate very gently and keep the speed under 35 mph. Of course you've had 20 minutes to consider where within that range you want to go and what story to tell when you get there ;-).

3.0 Maintenance

3.1 Charging (plugging in, charging times and tips)

Every time the car is charged, it is the beginning of what is commonly called a cycle. Ideally, each cycle begins with the batteries fully charged, and ends before the battery pack has been more than 50% discharged. Opportunity charging often results in a partial recharge, which extends the current cycle.

3.1.1 Procedure

To charge this electric MG, you can use either a 220 volt outlet (commonly used for electric dryers) or a standard 110 volt outlet (preferably an isolated 20-30 amp circuit). If a 220 volt outlet is available, use the adapter in the trunk and follow the procedure for charging from a 110 volt outlet after that.

To charge from a standard outlet, plug in an extension cord (kept in the trunk) to the wall outlet and the short charging cord which sits on the front bumper, passenger side. Make sure the car is turned off, the parking brake set, and the emergency cutoff switch is still in the "ON" position. Reach in to a push button on the charger just inside the front bumper and push it. If the charger starts, you will hear ventilating fans turn on both in the front and at the rear of the car. This charger is set to shut off automatically when the batteries are fully charged.

Normal use for most EVs involves driving and occasionally opportunity charging during the day and evening, plugging the car in for a full recharge overnight. After a fairly deep cycle it can easily take overnight (8-10 hours) to reach a full charge, depending on the quality of power available at the outlet. If an outlet is a great distance from the main fuse box, or is wired as a 15 amp circuit, it takes longer to charge due to losses in the household wiring. After a full recharge, reset the trip mileage odometer to zero, to make it easy to keep track of the miles this cycle.

3.1.2 Keeping a Log

Typical deep-cycle batteries used in EVs are good for 700-900 cycles before needing to be replaced. If they are regularly discharged more than 50% they will not endure as many cycles. Conversely, if most cycles are relatively light, they may last longer. The best way to keep tabs on this is to keep a battery log, numbering the cycles consecutively, noting the miles driven, and whether any opportunity charging was done that cycle.

Other useful information to collect could include any of the following data: + End of cycle pack [and/or individual battery*] voltage[s] + Start of cycle pack [and/or individual battery*] voltage[s] + Specific gravity of individual battery cells ** + Check whether any batteries are noticeably warmer than others at the beginning or end of charge The most reliable way to check battery voltage is to turn on the car heater, which draws ~15 amps, and check the voltage under that load (make sure the charger is not operating during this check). The slight load will yield a more reliable voltage indication than can be gotten under no load conditions.

* Since individual battery voltage checks and logging is time consuming we recommend it be done at most once a week. Under many circumstances once a month is sufficient to notice a trend.

** Specific gravity checks apply only to flooded cell batteries. Once every other month is sufficient for this, and can be combined with checking the level of the electrolyte (See below).

3.2 Things That Don't Need Doing any more

Change the oil or oil filter
Add anti-freeze or water
Get anything tuned up
Replace spark plugs
Get a Smog Check
Fill'er up
Replace muffler, fan belts, timing chain or hoses

3.3 Some Things Don't Change

The original suspension components and most of the drive train are usually retained in a conversion. These parts still require periodic checks for wear and/or adjustment. Since EV conversions usually weigh more than they did in their ICE days, this translates to more wear and/or stress on the parts of the car that were kept.

3.3.1 Check Tires Periodically

Tires should be checked and rotated a little more frequently than the original maintenance schedule calls for. Many EVs (this one included) have low rolling resistance tires which are inflated to higher pressures than normal tires. Tire pressure should be checked and corrected at least monthly, since proper tire pressure can have a big effect on range.

3.3.2 Brakes

The brakes are perhaps the most noticeably affected by the added weight, and tend to wear out faster than they did before. Checking the front disc pads and rear shoe adjustments every other month will allow you to track the wear and plan for replacement/adjustment as needed. When they need replacing, you may want to replace them with "metallic" pads, or ask your parts store if there are slightly larger pads which will fit you car than the standard replacement. 3.3.3 Lubricate and Check Suspension

The need for front end alignments and occasional replacement of shocks or other moving joints is unchanged in an EV. If the owners manual called for annual service and checks, these should still be done. Many owners counted on the manuals to be conservative in stating the time span between such checks. Again, given the greater weight and changed distribution, a good rule of thumb is to do these checks *at least* as often as originally recommended.

3.4 A Few New Things

Normal vibration during operation along with temperature swings can conspire to loosen battery connections. On your old ICE all this meant was that the starter might run slowly or not at all. On an EV, however, this can have dramatic and damaging results. Because of the extremely high currents, even a slight rise in resistance at the battery terminal can cause very high temperatures. On batteries with lead terminals, this can cause the terminal itself to melt, freeing the connected cable to make other hazardous connections. This can all happen very quickly. Therefore it is a good idea every 4- 6 weeks to check the tightness of each high current connection, cleaning and tightening as needed. This doesn't take long, and it is easy to correct a loosening connection before it results in damage.

3.4.2 Checking Battery Voltage

Most systems monitor the pack voltage. Although checking the electrolyte in wet cells with an hygrometer is sufficient, checking the voltages across individual cells under a steady load can quickly identify small variations in individual batteries, signaling a need for equalization and/or replacement of a failing battery.

3.4.3 Watering the Batteries

For flooded cell batteries the water level should be checked and filled once a month. Also check and clean the tops of the batteries at this time. Dirty battery tops can be the cause of current "leaks" to the car chassis and could be a potential hazard. Note: always check and add water to the batteries when they are charged; the volume of the electrolyte is grater then. This is also a good time to run an equalizing charge on the pack (after watering). To run an equalizing charge, adjust the shut off voltage to the maximum on the charger and charge the car at this max. voltage (approximately 163 volts DC on the battery pack) for several hours.

3.4.4 Replace Failing Batteries

A single bad battery in a pack has a negative impact on the whole pack, so if equalization does not bring it up to par, it is better to replace it quickly than to wait for it to degrade seriously. Either the voltage check or the specific gravity checks mentioned above are sufficient to indicate a battery that is under par.

4.0 Trouble Shooting

Most often this is because one or another of the safety interlocks is still engaged, or the main cutoff switch is in the off position. The main cutoff switch is operated by a push-rod located between the seats and extending under the car to the rear. The on and off positions are clearly marked. This is typically only switched off when working on the car as a safety precaution, although some drivers may turn it off when parking the car out of habit. Check to see that it is ON.

If the charger is plugged in, it disables the main contactor, so the next thing to check is whether the car is still plugged in. While charging there should also be a red light lit on the dashboard.

The next thing to check is the pack voltage. It should be between 100 and 151 volts at rest. If it is zero, or much lower than the specified range then there may be a bad connection or one of the in- line fuses may have blown. The main fuse is located in the rear battery pack. To check them, test continuity from one side of the fuse to the other. It will read open if the fuse is blown.

The main contactor is controlled by the ignition key. The yellow light on the dash is an indicator only and does not tell you whether the main contactor is energized or not. You should hear a "click" as the contactor switches on and you should see the voltage on the volt meter increase slightly. If this does not occur, then the in-line fuse to the main contactor may be blown.

4.2 Car Won't Stop

Although unlikely, there are certain failure modes that could cause the car to be full on. First make sure the accelerator is not stuck on. Place your foot under the accelerator and lift up. If this does not stop the car turn the ignition key off. If the car is still on, push in on the emergency switch to disconnect the main power. Try to avoid putting in the clutch and braking to a stop. This will work but it will most likely cause the motor to over spin and self distruct. This method also does not turn off the main power.

4.3 Lights/Fan/Wiper/etc. Won't Operate

Check the fuse to the particular accessory that is not functioning. These fuses are located under the hood on the left hand side as you face the car from the front. The fuses are under a black plastic cover. If all the accessories are dead check the voltage of the 12 volt system. If this is dead, check the in-line fuse to the DC to DC converter. Switch off the emergency disconnect when checking this fuse as the DC to DC converter is wired to be on all the time.

4.4 Charger won't turn on or main battery pack is not charging

Check the extension cord, circuit breaker and GFI reset switch on the AC side of the charging circuit. Try pressing the start push button on the outside of the charging box. Check the circuit breaker on the battery charger box and check that the emergency disconnect switch is on. If all these items are in order check the fuse inside the charging box. Switch off the emergency disconnect when checking this fuse. Last check the in-line fuse to the battery charger box. This fuse is located in the wire bundle on the right side of the DC to DC converter.

4.5 Flat Tire

Many EVs do not carry a spare tire. There may not be room or it may have been left out to reduce the weight of the car. The MG does not carry a spare. The spare would take up all of what is left of the trunk space allowing for no extra carrying space. The spare is currently in David Coale's garage. Since the range is limited and the tires are new this is not thought to be much of a problem. The jack for the MG is in the trunk if needed.

5.0 Technical Info:

Prestolite 20HP 96 volt DC Series Wound motor. The HP rating on this motor is a thermal rating for continuous use. Electric motors can operate at higher voltages and currents for short periods of time (acceleration, hill climbing) with out any harm. It takes about 20 HP to move the MG down the road at 65 MPH.

5.2 Controller

The controller is an Auburn C600, 144v, 600A controller with heat sink and cooling fan. This controller is a sealed pules width modulated (PWM) controller for DC series wound motors. The cooling fan is on when ever the ignition key and controller are on.

5.3 Batteries

Main battery pack; twelve, 12 volt SCS225 deep cycle Trojan batteries. These are flooded cell lead acid batteries that are suitable for EV use. These batteries have an amp hour rating of 130 amps at the 20 hour rate and weigh 66 Lbs each.

Accessory batteries; The 12 volt accessory system is made up of two 6 volt Power Sonic sealed gel cells wired in series. These batteries are connected in parallel to the DC to DC converter that is connected to the main battery pack. The DC to DC converter keeps the accessory batteries charged in much the same way as an alternator keeps a the starting battery charged in a gas car.

5.4 Wiring Diagram

The main battery pack is isolated from the rest of the car (negative side not connected to the car frame). This is for safety and to keep the main battery pack and the 12 volt system separate. The DC to DC converter is wired to be on all the time. This is to make sure the accessory batteries are always charged so that the accessories (ignition and hazard lights) are always available.

5.5 Suspension

This car has the original suspension in the front end, although the toe-in has been set to zero. The rear end leaf springs have been augmented by doubling several leaves until the original ride height and good spring shape were achieved. Otherwise the shocks and adjustments are unchanged.

Table of Contents

Technical Stuff

Project Main Menu

6.0 Appendix:

6.1 List of Suppliers ,EV Components

6.2 Information Sources (References)

6.3 List of Sponsors (Thanks)

The list is sort of in order of the donations received: Will Doolittle 1978 MG Midget Electric Auto Association, SV Chapter Prestolite Motor Curtis 1221B Motor Controller Bob Schneevies Adapter plate, used batteries, use of tools Otmar Ebenhoech Varisous Parts, use of tools, etc. British Motor Sports Engine trade in and MG parts Jebb Eddy Steam claen of engine compartment GNB Battery Comp. Battery Sponsorship Good Year Tire Low rolling resistance tires Bill Young Tires Balancing and mounting of tires Clare Bell Used batteries Maaco Auto Painting New paint job for the MG David Coale

David Coale                         ___o\____
(650) 493-4503               =)----/()_____()\

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