Help with electric car idea

I have an idea for an electric car that although is not new, I simply have not seen anyone go in this direction. Since I am only a hobbyist type of engineer, I and embarrassed to ask if perhaps I am barking up a wrong tree. Please bear with my ignorance as I ask a few simple questions and give you a brief description of my ideas.

I do not like the current crop of hybrid cars. although the technology is better than nothing at all it is only a minor benefit over none at all, and frankly almost all the hybrid cars would be better off as a efficient 4 cyl car, without any electrics.

I think they (the car manufs) have it all backwards. I envision an all electric driven wheel car, with a small 200-400 CC engine running on any type of fossil fuel (Diesel propane, natural gas, and or petroleum). this is a small unit designed to run at the most efficient speed (2500 RPM). It runs all the time it is needed to charge the batteries and also runs the Air conditioner, and any other "power" accessories that might be needed.

The batteries would be of efficient lithium ion type (probably 1-2 thousand of them). they could be arranged into any needed voltage levels. As well as the battery power and the electric engine (Could be dc or AC brushless) there would also be a shared shaft DC engine with completely different winding sharing the same shaft as the primary windings. what this secondary winding would do (Either AC or DC) would be to kick in when a large boost in power (initial acceleration and or passing at hwy speeds) is needed. I would like to ask if there is any large capacity capacitors that could be used to store energy and allow for a dump of 3-7 seconds of boost. Are capacitors available that are small. lightweight, and of sufficient size that they could be used in a gang style connection?

The little 200-400 CC engine could be run all the time or only when the caps are not full. The little engine would first fill the caps, then maintain the caps charge. After that the engine would charge the Li ion cells. It is also able to take a charge from the AC wall outlet, so that during the night your car would be fully charged. The little engine in the back could be used to charge when an AC wall outlet is not available and of course during the operation of the car to recharge the caps. What I really want is a minimum 20 HP equivalent from the main Li Ion batteries, and a 50 hp boost as the caps dump to the booster winding.

Does any of this make any sense? I do not know if I am describing it properly, and I beg your indulgence re my lack of formal engineering... But I am reasonably capable of machine shop use, and I have a couple of "well off" friends who might be interested in funding a prototype. Whet I do not know is if such capacitors exist in the size and weight I might need.

Any ideas, would be appreciated...

If you could.... A CC to my email address of would be appreciated....

Thanks in Advance.

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In principle, there is some sense to at least most of what you say. The problem is that it requires engineering. That is, the problems are in the details you do not provide.

There has been recent work on capacitors which may or may not end up doing your peaking. Charging and discharging capacitors can be a lossy operation if not handled well.

To bottom line it another way, I am not ready to invest in your ideas.


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As for your battery choice.

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Seems the lithium batteries do not like it warm. Nor cycled very often. That leaves out a lot of the densely populated areas of the south and west for sales. Lets see each cell weights ~2 ounces times a thousand equals about 125 pounds. Probably not enough power there to go to the corner. It runs in my mind that the GM EV batteries weighed about 2000 pounds. Your concept is a long way from 20 horse power. I personally have seen my share of capacitors go nuclear in industrial settings. I would not choose to get into a vehicle with them as part of the power circuit. Wonder what would happen in an accident greater than a fender bender. The utilities use caps for power factor correction. They are beefy and make one hell of a bang when the grenade.

Sorry to be the doubting Thomas, but I think your idea is full of holes. To many holes to be salvaged. Do you have any voc tec schools near? Check with them and see if they have an electric program. Go volunteer for awhile. Then maybe you will have a flash that can be called genius. That's what I did. Sure awakened me up. I even volunteer for the universities solar racer once in awhile. That baby cooks, 80 mph for 20 miles. Does not meet DOT specs and can not be driven at night. There are no headlamps. Donated parts are now approaching 6 million bucks.

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You are still describing a hybrid. The first hybrids were better than the current ones since they had smaller engines. The problem is Americans still want performance and that requires energy. You still can't get something for nothing. Basically a hybrid only tends to level out the energy demand. If this is stop and go driving, without too much drag racing there is a big saving to be had but if you keep your foot in it, you are burning energy and thay has tro come from somewhere. At interstate speeds that saving, starts to fall off.

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That type of car is in design for the last 10 years. One issue was a electric motor on each tire, or one central one.

Google it.

Reply to
night dalits

Please correct my arithmetic, anyone - it is a lovely sunny morning and I am just waking up...

Storing enough energy to provide 50hp for 7 seconds? Call it

50kW and you have 350 kilojoules. With capacitors at around 350joules/kg, your capacitors are going to weigh 1000 kg. They are going to be a tad large too..

Not my field and the figures above are just ones plucked from Google. Others more experienced in this area might like to correct me.

One thing I do have experience of is injuries caused by capacitor failure. Very messy. If all those joules let go in a fraction of a second, it could be quite "interesting".

Personally, I have this idea about tamper-proof cartridge battery packs. You drive your electric car into a "filling station". The pack is slid out and a value given, depending on what a sexy little processor built into the pack says its life story has been. A replacement, charged, one is slid in and you pay the difference. You can even have a dashboard display showing current (hic) value and well as current (hic) capacity..

You could even choose how much you wanted to pay - by choosing the replacement pack. If you were skint, you could even swop your nearly-new but depleted pack for a very old but charged one - and get money back.. Plus keep a spare in the garage and/or tow a spare for extra range..

The filling station would, for a fee, be recharging the pack(s) using power utility power.

It must have been thought of..

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Warning! Rant ahead! Move on if you don't have the time!

There is a basic problem with all of these ideas. Convenience. We want to be able to get in our vehicles, drive to where we want to go, and get out after we park it. Occasionally we will put up with stopping to refuel, but many studies have shown that if it is any less than every

250-300 miles or so, people consider that a nuisance. That is why you see 25+ gallon fuel tanks on monster SUVs that get 10MPG. Those people don't care about economy, they just don't want to stop at the gas station every 2 days to refill. ELECTRIC VEHICLES CURRENTLY AVAILABLE THAT NEED TO BE PLUGGED IN FOR RECHARGE AT THE END OF EVERY TRIP HAVE NEVER TAKEN OFF BECAUSE OF THIS. Even the "power pack" idea is impractical. If I had to stop and swap out power packs every 2 days, I would trash that thing in under a month!

Hybid cars are not just about recharging the batteries in as much as providing a usefull range. The big problem with electric powered vehicles has always been range. You can go 70, maybe 100 miles betwween recharges, but then the recharge process takes too long to be usefull for most commuters. Internal combustion engines are actually quite good at converting chemical energy to motion at a constant rate, but are extrememly inefficient for acceleration torque and idling, making them wasteful for stop-and-go traffic. The hybrid is a way of supplementing the lack of range of the electric motor by having the gas engine take over for the long hauls when they can operate at peak eficiency. The electric motors provide better acceleration efficiency and can allow the entire system to shut down when not moving at all.

Having the internal combustion engine idle continuously and soley to keep recharging batteries is just increasing the wastefulness. You lose 25-30% of the available stored chemical energy in the conversion process alone. In addition, 400cc's of I.C.E. will net you about 5kW (6.7HP) of generated electric power under the best of conditions. If you are running even just 20HP of electric motor, you are using energy at a rate of 3x the recharge rate. How long do you think you can run that motor before you deplete your stored energy capacity? The only way it could possibly work would be to allow the I.C.E. generator to run even when you were not using the vehicle. So what have you saved?

Electric motors are really good at only using power as it is required, so the whole capacitor thing is pointless anyway. Put a 50HP motor on it if you feel it needs 50HP for acceleration, but when it needs only

20HP to maintain speed, it will only draw power related to that 20HP load requirement. The only problem with electric motors is that the power it consumes must be carried with it in some form. The batteries to carry around enough chemical energy storage for a 250 mile trip still weigh too much. Trust me, there are a LOT of people working on this issue all the time, and it is not easy to significantly change the formula. Hydrogen has promise for the future, but the storage issue is still a big hurdle there as well. Solar is quasi-"free", but too slow to be practical for transportation. Capacitors can store a lot of energy in terms of voltage, but not a lot of net power since they will dissipate that voltage relatively quickly. As a point of reference, a capacitor bank for a 20HP VFD can hold up the electric motor for about 1 cycle, or 16.7 milliseconds when the line power is turned off, and weighs approximately 1 pound total. So if you extrapolate to your wanting to run the motor for only 7 seconds, it would likely weigh 400+ pounds, and what good is 7 seconds going to do for you? You still need batteries. Then the energy to recharge that capacitor bank is going to be robbed from the charging cycle of the batteries, furthering your energy deficit from the little 400cc I.C.E. generator.

Conclusion: In the world of portable power sources, an I.C.E has yet to be bested. I do think that the I.C.E. component of the currently available hybrid vehicles could probably be improved by being diesel, but here in the US we have a lot of environmental concerns associated with small diesel engines so it may not be practical at this time. I bought a Prius in 2001. I think it is one of the finest examples of engineering compromise in human history. I don't get the advertised

50+ MPG, but I do average 44 MPG fairly consistantly, and coupled with an 11.9 gallon tank, I can go a little over 500 miles between fill-ups. I doubt anyone can beat that with an all electric vehicle.

Rant complete. Time to go back to work.

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Well, I have a different look at it. Yes, finding a place to 'plug in' in every parking lot is a problem for sure. But another one is "Why should I have to have two different kinds of cars?"

For the daily commute, an EV would work for a lot of folks. Just park at work and plug-in when you get home at night. So the only charger socket one needs is in the garage.

But for long-distance trips, even if every filling station on the interstate had a 'socket', who wants to sit around for four to six hours after driving for just two?? So, one needs a *different* car for visiting grandma's house on Thanksgiving, or spending the weekend at the beach?

Two different cars, different mechanics, maintenance schedules, parking spaces.... Easier to just have one car that does it all. Or if a family has to have two cars, it's still easier to have two with the same technology.


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The snipped bit was suggesting that the complete power pack be swapped at "filling stations". It could be as simple as driving over an "X" and a fairly simple mechanism could pull out the existing pack and shove in a replacement - almost certainly in far, far less time than it takes to refuel a conventional vehicle.

You may have to swap packs more often than you fill a tank - but the total time could easily be comparable.

Certainly you could also have recharge facilities at home and elsewhere (ISTR power outlets on parking meters, for plugging the sump heater into, in Canada, in Winter - do they still exist? We have never had them in the UK).

The "filling station" could be of radically different design and easily combined with other things - eg a combined drive thru fast food/ATM/etc and "filling station".

Of course, it would help if all vehicles took a "standard" battery pack and had a common exchange port design.

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The power pack swap scheme was illustrated on the cover of Popular Science sometime in the late 1960's - early 1970's. As I remember it, the artist's concept showing the grid assembly being lifted out for exchange while the old electrolyte was pumped out so that fresh fluid could be pumped in. That sounds like some 1920's auto battery repair manuals I've seen.

An updated version of battery swapping could merge two business models that exist now, at least in the U.S.: "15 minute oil change" type shops and the propane tank exchange that can be found mostly at convenience stores. The drawback is that aging battery packs aren't as easily refreshed as propane tanks. Maybe the pack could have its own meter showing available kWh, and you would pay for the available energy in the fresh pack while receiving some credit for the remaining charge in the used pack.


Reply to
Mike Lamond

The credit concept was something I had in the snipped bit -=20 but a bit more sophisticated than simply a meter showing=20 available kWh. I had in mind a tamperproof microprocessor=20 system that would store the life history of the pack. So its=20 age, number and depth of discharge cycles, number of swaps,=20 even previous vehicle types etc would all be available it to=20 produce a commercial value for the battery pack - which=20 would be the credit off the replacement unit (which may=20 actually have a lower value, if it is an old pack replacing=20 nearly-new). So, when you drive up, instead of choosing how=20 much fuel you want, you choose the value of the replacement=20 unit, from those that are in stock at the time..

This is going even more OT but I hadn't heard of these=20 propane tank exchange - is this for propane-powered (or=20 dual-fuel) vehicles? And they really do remove and replace=20 the tank? Ta!



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Good point, I like your logic. But to address your "charging station" issue for commuter cars, I had an all-electric car for a while. I commuted to a rapid transit system station in the SF Bay Area (B.A.R.T.), and they provide a free plug station at the parking lot for EVs. It was great when there were only 5 of us EV users using the

6 plug stations, but one day I arrived to find them all filled, and when I got back to the station that night, I didn't have enough charge to get home. In other words, the logistics of even having an EV strictly for commuting are very problematic.
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OK, instead of focusing on the relatively minor issue of technology involved in tracking battery life (and I doubt that it is in any way minor), lets look at some quick internet data on the logistics just for the US (since that is where I live and have information available).

As of Y2000, there were 195,455 stations where gasoline can be purchased.

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For simplicities sake, lets assume there were 204,000 by 2003.

Also in the year 2003, there were 204,000,000 gasoline powered household vehicles in use in the US, the ones that would be eligible for conversion to EV technology.

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That means each service station must be capable of handling an average of 1,000 vehicles (assuming even distribution of course).

The average number of miles driven in 1998 was 11,725 per year. (same NPN report as above). Again, for simplicity, lets even assume we can all cut back to 10,000 miles per year (LMAO).

1,000 vehicles x 10,000 miles/yr = 10 million miles driven by customers for each available service station.

If you can get, lets say, 100 miles out of a battery pack (and that would be a stretch), that means each service station must be capable of changing out 10,000,000 / 100 = 100,000 battery packs per year!

Assume we can miraculously design a machine that can change out a set of battery packs in 5 minutes, including the time it takes for each driver to line up on the "X" (again, LMAO). Another side-splitter: getting the industry to standardize on battery packs being universally interchangeable! ROFLMAO!

Let's now also assume that a service station can afford to install 4 of these machines (big ASSumption), and that each service station runs

12hrs/day (720 minutes). 4 machines, x 720 mn/day continuously = 2880 changeout minutes capacity. At 5 minutes per customer = 2880/5 = 576 customers per day if they are all lined up ready to be charged. 576 x 365 days = 210,240 customers per year capacity versus the 100,000 minimum capacity, so that part is doable when you consider the real logistics of how people would refuel.

If each machine cost only $50,000 installed (LMAO again), x 4 machines per station, each station would need to invest $100,000 in the machines alone. Theoretically doable again, but to make it work, the service stations would need to cough it up PRIOR to everyone switching to EVs, but lets move on from that side track.

So as a whole industry, 204,000 stations buying $100,000 worth of machines makes this an $20.4 billion dollar investment!

Now lets not forget the cost of moving and storing 100,000 battery packs per year added to that. 100,000 battery packs / 365 days = 274 packs per day to handle assuming a steady flow. That is roughly 23 / hour in that 12 hour day. That's a lot of weight alone, too much to expect a person to manhandle, so assume at least 1 fork lift for each station, Add another $20,000 investment for each station, bringing it up to $120,000, or almost $25 billion in up-front infrastructure investment for the service station industry. Not looking so good any more as a big picture.

Now the batteries themselves. 100,000 battery packs need to be used at each station per year, which as shown above is 274 packs/day in a 12 hour sales day. Assume that you only need to actually carry 1/2 of those in stock, because you have the other 1/2 being recharged, and it takes 1/2 of the day to recharge them (complicated logistics however). So now the stations need to buy 137 battery packs. 137 battery packs x

204,000 stations = 28 MILLION battery packs! Assume, what, $500/battery pack? (another laugher because the replacement batteries for my Prius are more than that, and they don't need to run the car full time) Now you have an overall UP-FRONT battery investment of $14 BILLION dollars! Makes the machines look relatively insignificant. I want into the business of making battery packs!

So $25 Billion in machine installations plus 14 Billion in batteries is now at $39 Billion in infrastrcture.

Now add to all of this the cost of everyone switching to EVs. ASSume you can get the price of a reasonable EV down to $25,000, roughly the cost of a Prius right now. 204,000 vehicles x $25,000 / each = another $5.1 Billion investment as a society in EVs.

To all of this we will leave out the cost to society of disposing of the gas vehicles, gas tanks at service stations etc. etc., as well as the eventual cost of disposing of spent batteries.

Now consider that the US used $205 Billion worth of gasoline in 2002

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nearly 1/2 of it was used on commercial trucks, busses and motorcycles (NPN study), and so not available as savings by switching to EVs. With $110 Billion in annual gas sales being displaced by making a $44 Billion investment in EV's and infrastructure, it appears to make some sense as a society. But with getting anyone to cough up that kind of up-front investment AND suffering the economic impact of telling 1/2 the petrochemical industry to just go away, it is not likely to happen.

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The same arguement could have been used when horses were replaced by automobiles. Substitute hay and oats for gasoline, blacksmith shops for gasoline stations, paved roads for lanes, etc. And the pollution from the horses could be used as fertilizer not like the pollution from autos. I could park my horse in any meadow and it could fill itself up while I worked. And, unlike an auto, they were self-replicating.



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But the analogy is erroneous. Automobiles quickly became so vastly superior to the horse that any comparison leaving that superiority out is flawed. In the battery vs gasoline "debate" the two vehicles are roughly equivalent, with the present performance superiority going to the existing technology, not the new.

A battery powered vehicle will have to offer significant benefits over the I.C.E., as perceived by the consumer, before it replaces existing technology to the same degree that the auto has replaced the horse. But it won't be in line with the dicsussion which seems to center on relatively "overnight" replacement. A phased in approach is more likely, and is in fact what is happening. How far it goes remains to be seen.


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I'm not disagreeing with you. There are always problems with the introduction of new technology. How do you sell pre-recorded tapes to people who only have record players? How do you sell CDs to people who only have tape recorders? How do you sell DVDs to people who only have VCRs?

My feeling is that we will have to go to all electric eventually. Some sort of battery will have to be devised that lasts the life of the automobile. My '71 Jag still runs on gasoline 34 yrs later. What will I do for batteries 34 yrs later with any battery car I buy? And the source will have to be nuclear; anything else is a pipe dream. We have go get over our collective consciousness of nuclear danger which was embedded into up as kids in the '50s.


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You left out the cost for additional power plants, dismantling the existing refineries and underground lines used to move fuel across the country, and the fact that the pollution is moved from the vehicle to the power plant.

What happens when there is a fire at a charging station with all those spare batteries? Does the site get added to the super fund list?

Do you want high current charging equipment near a place that has thousands of gallons of gasoline in underground tanks where the fumes could be ignited by a spark?

Reply to
Michael A. Terrell

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