THE Electric Vehicle (EV) Thread pt 1 (merged) Archived

[Whitecrab]

Electric vehicles exist today, and they work. They are not yet mass produced, sure, and you have to use expensive batteries and light material and still get less range then a normal tank of gas. The biggest problem is the batteries: although cheap to charge and in some cases maintenance free, it's very difficult to design a battery that is long lived, maintenance free, takes many charges, stores a lot of energy, and can deliver sufficient power. Everything else about an electric car sounds solved to me.

However, we have a whole plethora of battery designs that are in the "decade away" category. Advanced lead. Nickel metal hydride. Nickel...there's about a half dozen nickel-pair batteries in the works. Suflur-based batteries. Alluminium air batteries. We have a lot of different materials that may all be able to pay off, meaning we have a fair chance of getting at least one working within a decade, and we may eventually have several options (which helps alleviate the "well what about peak nickel?" problem. Recycling helps, too). We can assume that if the technology is in place and the peak hits, the automakers will finally feel enough push to develop the damn thigns properly.


Most electric vehicles on the market today take hours to charge, can only go about 30 m.p.h., and can go <50 miles on a charge. Mostly because the good protoypes are held back and EVs are used just for airport busing and golf carts. However, most of the new generation of batteries are promising ranges of 150-300 miles (about half a full tank of gas, and perhaps more), and charing times in the range of a few hours to as low as 15 minutes! Overall, the EVs will cost about the same as a normal car: more upfront for the batteries, but less in maintenace and fuel. EVs may never attain the range of a regular car, but is it really so bad?

Supposing you can get a truck working with a comparable performance. That means, at least until technology further improves, maybe the trucker has to stop twice as often and charges for a few hours at each stop. Although he's saving tons of cash on gas. That would mean that trips that once took 3-5 hours and full tank of gas might take a full day now, because you have to blow a few hours charging. Trips that took longer could probably be shunted to trains, or trucks running on what little oil or biofuel we can manage to produce. It's still quite a step up from shipping goods by horse.

That's not so horrible, is it? And if an electric vehicle means going to the cottage involves charging for a few hours at a tourist town along the way, that's not so bad. If it's really a cross country tour you take the train or rent a gas car. It's a lowered standard of living, but it seems reasonable to me that - if we can solve the natural gas crisis with renewables/conservation/nukes - we can solve most of the land based transportation if just one of the dozen battery technologies manage to pay off. The average daily commuter can charge his car at night, when power is cheap and under utilized anyway.


Is there any reason for more pessimism? Can anyone provide estimates on how much metal that would cost?

[OilBurner]

Let's wait and see. You're saying range in the 150-300 mile mark. Is that with a regular sized vehicle that a family can use or a golf cart sized prototype?

In any case, 300 miles I could live with, but 150?? On that end of the range it just isn't going to sell.

These new batteries better be longer lasting than current ones, most mobile phones I've owned start to lose their charge capacity very quickly. I wouldn't want to have to keep replacing the battery in the car every year to keep a decent range. Still, with no fuel bill you'd have quite a budget for maintenance and still save a lot of money overall.

Fingers crossed though. I'd buy such a vehicle if it met my needs.

A little off topic, but I wonder if EVs took off (not literally!!), would manufactuers have to add a fake engine noise to stop a massive increase in pedestrian fatalties? Has anyone even thought of this or are they too busy trying to strech another 5 miles on the range?
Let's face it, many people are too dim or lazy to actually stop and look before crossing a road!!

[Devil]

Electric vehicles generalised? No way, unless you want hundreds more nuclear power stations to keep the batteries charged. As a rough guideline, you will need 4 1.6 GWe nuclear reactors for every million mid-sized cars or twice that number for electric SUVs. And don't talk about wind or solar. Nobody wants their cars to not start in the morning because weather conditions are not favourable.

There is NO way that the electricity grid in any country I know of could cope with the extra load: as a rough guide, it would require tripling the capacity.

[OilBurner]

Triple the capacity? Whoops!!

It seems range and battery life are the least of our concerns then!!

[PhilBiker]

There are important advances in electric motor efficiency that can get a lot more power out of a given charge. I read a good article about this in the Washington Post Magazine one Sunday a few weeks ago.

[Devil]

Electric motors have been getting efficiencies of 90-95% and even more for decades. It would be great if the "important advances in electric motor efficiency" could take it up to >100%: THEN, we would have the perpetual motion machine!!! :D And have a "lot more power".

[lowem]

The batteries, dudes, the batteries! 2 orders of magnitude too lousy!

[Devil]

Lousy = too big and too heavy with too short a lifetime for too high a cost. That is why the hybrid wins hands down; the battery is small.

[Doctor Doom]

Cars with specs better than that already exist. The Toyota RAV4 EV, discontinued in 2004, could go freeway speeds and had a 100 mile range. It takes hours to charge up. The batteries are the real problem; batteries are a factor of 100s (like 400x) worse than gasoline in energy storage capacity per unit weight. With batteries 10 times better than the best we now have (unlikely ever to be developed), you would still be off by a factor of 10+ versus chemical fuels. And they will continue to require a lot of time to recharge because there are limits to how much electric energy you can push through a reasonably-sized wire in a given period of time. Already you are seeing prototype power packs for laptops that use methanol fuel cells. Finally, a lot of people (like me) don't have any place we could charge an electric vehicle (I live in an apartment). I think electric cars could find a niche as commuter cars for people with houses and another petroleum-powered car for general family use. The issue is that it's very hard for most families to justify the expense of a car whose use is limited solely to a short-range once-a-day commute. This is why I think plug-in hybrids are a more likely way forward.

[Whitecrab]

Let's wait and see. You're saying range in the 150-300 mile mark. Is that with a regular sized vehicle that a family can use or a golf cart sized prototype?

In any case, 300 miles I could live with, but 150?? On that end of the range it just isn't going to sell.

These are full sized cars, in some cases ones that can win racing competitions. The cars are designed to be as light-weight as possible, use composites instead of metal, be aerodynamic, etc., but then again so are hybrids.

From this 1997 book I'm reading: Some 40 million households in the US have 2+ cars, and 90% of these second vehicles travel less then 30 miles a day. According to the US Dept. of Trans., the average commute is only 12 miles, and the average travel for all purposes is less than 30 miles. Only 25% of all commutes exceed 60 miles in length, and 90% of all vehcile trips are under 60 miles in length.

So now you rent a normal car or hybrid when you have a long trip, or take the bus or train. Boo hoo. In return you get ridiculously cheaper fuel, and a low maintenance vehicle. Every few years maybe you have to replace $5,000 batteries, or something, but you don't have to pay for literally dozens of components that an internal combustion engine relies on.

A little off topic, but I wonder if EVs took off (not literally!!), would manufactuers have to add a fake engine noise to stop a massive increase in pedestrian fatalties? Has anyone even thought of this or are they too busy trying to strech another 5 miles on the range?
Let's face it, many people are too dim or lazy to actually stop and look before crossing a road!!

I'd thought of that myself. I remember reading an article about a hybrid owner who wasn't sure whether he should be honking his horn in an underground parking garage, to warn people he was there! (The battery was fully taking over at low speeds).

There is NO way that the electricity grid in any country I know of could cope with the extra load: as a rough guide, it would require tripling the capacity.

Electric vehicles are even bigger money gains for the utilities, because they can be charged largely during off-peak hours in the night, allowing companies to make a tidy profit instead of under-utilizing the grid. Solar is about the only thing that doesn't work at night. It's been estimated each electric vehicle is a bonanza of several 100-$1000 over it's life.

This flow of cash from oil companies to power companies, and from trade debt to in-country generation, would help provide the cash at least to make this more feasible. (You don't need to point out that there's more to building plants fast enough then cash :D)

[kenbathrhume]

I think electric cars have a good future.

The batteries need some improvement.

I think they'll be a couple versions. One type you'll drive 50-100 miles and then recharge. This wouldn't be practical for long trips, so families would have 2 or 3 cars. 2 would be 100 mile jobers and 1 longer gasoline or gas/electric vehicle.

Another type of electric would be a plug in hybrid. It would have enough battery power for 50 miles at full speed. You'd also have a small engine, like the Prius and use that on long trips.

As to how much power you'd need....last year the US produced and used 4 trillion kwh of electricity (kilowatt-hours). Each kwh is say 10c, so that's about 400 billion $ of electric.

A gallon of gasoline has 36 kwh of energy. We used about 150 billion gallons of gas. So to replace that you'd need 36* 150 billion or 5.4 trillion kwh of energy. So this would mean a doubling and then some.

BUT WAIT!!!! Gasoline to wheels is 20% efficient at most. Electric to wheels is much MORE efficient. Maybe 4x. Also electric vehicles would be smaller and lighter. There's no reason to think that in the future people will be driving 8000 pound SUVs. If there is a true "crises" then prices will rise and people will switch to cheaper, lighter vehicles as much as they can.

As to the "4 1.6GW of nuke plants for each million vehicles" I don't know if that's right. Sounds high. A 1000MW (1GW) nuke plant will produce 8 billion kwh of power per year. Given gas is 36 kwh/gallon but only 20% efficient it's effectively 7.2kwh per gallon. So that's about 1 billion gallons from the nuke plant (equivalent).

1 billion gallons would feed 1 million vehicles 1000 gallons per year each, so if they're getting 20 mpg they could go 20K miles per year. So I think that 1.6 number is off by a factor of 6 or 7. If it's not then show me where my assumption is off. ASsumptions are

a) energy efficiency of gasoline (effective)
b) energy efficiency of electric (effective)

To replace all gas would take 1/4 (because it's 4x as efficient) * 5.4 trillion kwh to replace ALL gasoline, or about 1.3 trillion kwh, which is about 1/3 of what we use now.

1.3 trillion kwh is about the output from 150 nuke plants. We currently have 100. The 100 or so produced about 800 billion kwh last year.

And that's for replacing ALL gasoline. We'd still have some oil, lots of it actually so we'd be replacing gasoline with electricity SLOWLY. So need to triple the grid.

Also much of the recharging is at NIGHT, when the grid is underused anyway.

It's one solution to the puzzle I think, along with conservation, diesel, higher efficiency in general, etc.

Oh and the battery energy density. You'll probably never be able to drive 300 miles on batteries and fill up in 15 minutes and drive another 300 miles. The batteries would be too heavy. That's where the plug-in hybrid would come in.

Anyway, gas is 36000 wh / gallon which is about 12000 wh/ kg. Batteries are quoted in terms of 10 wh/kg (lead acid) or 100wh/kg (lithium) or 45wh/kg (Prius NiMH batteries). So they're less dense by a factor of 100 or so for lithium. Lithium is supposed to be able to get up to at least 200wh/kg. Also gas is only 20% efficien, so only 20% of the energy in gasoline hits the wheels. So effectively it's only 2400wh/kg.

So if lithium becomes 200wh/kg it's 1/12 as dense per weight as gasoline (effective). That's not too bad.

A small car (like a Corolla not an electric small car) could probably get 4-5 miles per kwh electric, so with lithium batteries at 200wh/kg you'd need 10kwh to go 40-50 miles. 10kwh would be 50kg or 110 pounds. The equivalent weight in gas needed would be 1/12 * 110 pounds or 9 pounds which is about 1.25 gallons. A small car could go 40-50 miles on 1.25 gallons of gas.

With the success of the Prius, alot of money is flowing into making lithium ion batteries into hybrid and eventually plug in hybrid batteries. We'll see. Right now the impediment is cost. Lithium ion is $500/kwh of energy. So the plus in hybrid with 10kwh has $5000 of batteries. But prices should come down.

Also on a per mile basis the electricity alone is much cheaper than gasoline. 2c / mile (8c/kwh and 4mile/kwh) vs. 10c/ mile for gasoline ($2/gallon and 20mile/gallon). So partly the battery cost isn't as much of a problem as you'd think because the electricity per mile is so much cheaper. If $5000 of batteries last 100,000 miles then that's an additional 5c mile in transport costs. Still cheaper than gasoline.

[kenbathrhume]

Should say "no need to triple the grid".

[Devil]

BUT WAIT!!!! Gasoline to wheels is 20% efficient at most. Electric to wheels is much MORE efficient. Maybe 4x. Also electric vehicles would be smaller and lighter. There's no reason to think that in the future people will be driving 8000 pound SUVs. If there is a true "crises" then prices will rise and people will switch to cheaper, lighter vehicles as much as they can.

Wrong! The average to wheels efficiency of an ordinary mid-sized car today is about 35%, rising to 55% for a hybrid.

Also, electric cars, size-for-size, are much heavier. You can't compare a Hummer with a Corolla, and they will still drive Hummer-equivalents, if they are available. Electric to wheels is typically 80%-85% efficient, provided you have regenerative braking and know how to drive them, but electric to electric in the battery (when it is new) is, at the best, 70% efficient, so the overall efficiency is 56-60%, hardly better than a Prius. Of course, having to accelerate the extra weight of the batteries will require more energy, so the actual energy consumption will rise on a size-for-size comparison.

If everyone charged an electric vehicle each night, the current (pun intended) grids would still be greatly inadequate and would require at least doubling. In reality, it would be tripling, because everyone arriving at work at 8.30 or whenever will need to plug in again for the evening commute back. This is no miracle.

Of course, it would save energy if there were a legal weight limit on drivers and passengers of, say, 75 kg for men and 60 kg for women with swingeing fines for overweight persons in cars :D

[PhilBiker]

Electric motors have been getting efficiencies of 90-95% and even more for decades. It would be great if the "important advances in electric motor efficiency" could take it up to >100%: THEN, we would have the perpetual motion machine!!! And have a "lot more power".

The problem with today's electric motors is that they are designed to run at one speed and need to be geared or transmissioned somehow like a gasoline engine. This means it's only running at maximum efficiency at one "speed". There is much work underway on a variable electric motor which would not need a transmission, but are set up to run at various speeds. The pioneering work in this area has been done by competitors in the various worldwide solar car races in the last 10-15 years. There was a very good article on one company trying to get investors to start producing these in earnes in the Washington Post Magazine a couple months ago. Here's a little description:

http://www.theverylastpageoftheinternet ... _motor.htm

This type of motor has been prototyped and run for years now, it is not just "theoretical", but practically applicable. It can be mass produced with not much more thant the normal start-up time of any production facility.

[Devil]

Do you really believe everything you read in the Washington Post? Yes, Conceptual Solutionz has been trying to get venture capital for a long time, based on this idea. I agree that AC "squirrel cage" motors are efficient only at a single speed, just under synchronism, but there are two ways of achieving high efficiencies at variable speeds. One is to use AC motors with a DC>AC converter running at variable frequencies. This good for a wide range of speeds but it has a relatively low starting torque, so is no use for traction purposes. The other is to use the stepping motor principle, which offers both high torque at low speeds and high efficiency. Multiphase stepping motors have been around for decades. In fact, they resulted from the development of power semiconductors, needed to drive them.

The motor, as described in your link, seems to use a similar type of pulse sequence as a single phase stepping motor, from what little I have been able to glean. If I understand it (I'm not sure), it would seem to use a series of radial solenoids pulling round a crankshaft. This could work, but the efficiency and reliabilty must be lower than a straightforward multiphase stepping motor, as the mechanical conversion from a reciprocating to a rotary movement must involve losses (this is the key advantage of the Wankel engine over a conventional piston engine).

As a Chartered Electrical Engineer and an MIEE, I must register my scepticism. Unfortunately, their web site, www.conceptualsolutionz.com does not even appear to have a Home Page, so I can glean no info there; don't you think they would publicise it, if it were so wonderful? The only useful info I could glean was that the shareholders of a venture capital company, IT Corp. have been up in arms, because they considered that capitalising the "inventors" was throwing money down the drain.

I also bring the following to your attention from the link you cited:

However, a Canterbury University professor of mechanical engineering who saw the motor at the Innovate conference this month said the design was large and complex and he would be surprised if it was more efficient than a conventional electric motor.

"We see crazy designs for things that work but are never going to find a foothold in the market," said Professor John Raine. "Any new design of this kind has to be able to demonstrate a decisive advantage in some area, such as energy efficiency or power to weight ratio or manufacturing cost advantages."

Finally, there have been many designs for electric traction motors with very high efficiencies and starting torque. These vary from hub motors on each wheel (disadvantage is a high unsprung weight gives an uncomfortable ride, as it needs a soft suspension) to 4-wheel and 2-wheel drives from independent inboard motors (all of these direct drive with electronic differentials) to one single motor and conventional mechanical drives.

The electric motor is NOT the problem for traction. The batteries ARE the problem.

[Guest]

BUT WAIT!!!! Gasoline to wheels is 20% efficient at most. Electric to wheels is much MORE efficient. Maybe 4x. Also electric vehicles would be smaller and lighter. There's no reason to think that in the future people will be driving 8000 pound SUVs. If there is a true "crises" then prices will rise and people will switch to cheaper, lighter vehicles as much as they can.

Wrong! The average to wheels efficiency of an ordinary mid-sized car today is about 35%, rising to 55% for a hybrid.

Also, electric cars, size-for-size, are much heavier. You can't compare a Hummer with a Corolla, and they will still drive Hummer-equivalents, if they are available. Electric to wheels is typically 80%-85% efficient, provided you have regenerative braking and know how to drive them, but electric to electric in the battery (when it is new) is, at the best, 70% efficient, so the overall efficiency is 56-60%, hardly better than a Prius. Of course, having to accelerate the extra weight of the batteries will require more energy, so the actual energy consumption will rise on a size-for-size comparison.

If everyone charged an electric vehicle each night, the current (pun intended) grids would still be greatly inadequate and would require at least doubling. In reality, it would be tripling, because everyone arriving at work at 8.30 or whenever will need to plug in again for the evening commute back. This is no miracle.

Of course, it would save energy if there were a legal weight limit on drivers and passengers of, say, 75 kg for men and 60 kg for women with swingeing fines for overweight persons in cars :D

WRONG!! Fuel to wheels in a gas car is nowhere near 35%

http://www.toyota.co.jp/en/tech/environment/hsd/04.html

Toyota says their hybrid tank to wheels (with reg. braking) is 37%. All other sources I've read for average thermal efficiency is 20%.

The US uses mostly non-hybrids so the 20% figure would be closest. That's the end energy we have to replace. So batteries ARE 4x as efficient if wall to wheels is 80%.

Also the 37% tank to wheels includes some regernative braking. The actual thermal efficiency to wheels is less than 37% w/o braking.

As for the grid, if everyone recharges for 3 hours at exactly 8 o'clock, then yes, it would be a problem, although industries use much less energy at night so it may still be possible. Another alternative is to have timers.

High prices for batteries and such would mean people wouldn't drive Hummers. They may be able to if they want to but it would cost more...and part of the cost would be updating the grid, if need be. Also the batteries for 50 miles are only 100 pounds as I mentioned. Not a deal breaker. In realithy, work vehicles would probably be mostly diesel for a long time. It's not like there will be no oil in 10 years, just that there may be less of it and it will cost more.

[Guest]

I should say "all other sources I've read" give 20% thermal efficiency (at best) for STANDARD Otto cycle engines. Toyota gives 16% on their page.

[PhilBiker]

Oops Devil my last post was poorly worded. I didn't mean to suggest that that particular link was the answer to all the worlds energy and transportation problems, it just represents a new technology to improve on the practical efficiency of electric motors for vehicles. Actually the article in the Post didn't talk about that group of researchers, but another group, I don't have time to look for the article right now. There -are- big improvements to be had in practical electric transportation efficiency.

[Devil]

The point I'm making is that, by the time you have generated and transmitted the electricity to charge your batteries, discharged them through a motor and transmitted the mechanical motion to your wheels, your overall energy usage to travel n kilometres in a given type of car is so great, you would have obtained better results filling a tank with liquid fuel.

To better complete the analogy, let's, for the sake of argument, imagine the power station burns oil. Then calculate how much oil you will need. Believe me, the overall efficiency will not be greater than if you were driving a Ford Model T. Then add the cost of the necessary infrastructure, and the cost will go sky high, as well.

You cannot isolate the parts of a process that suits an argument. You must take the holistic view (I haven't, entirely, because I'm assuming the wellhead to power station and the wellhead to fuel pump costs will be substantially the same).

[mgibbons19]

Why on earth would we try to deal with this by switching cars around? The car and the modern 'burb are the perfect evolution of oil driven transportation. Trying to retrofit electric onto that infra/structure will be expensive and inefficient.

Why not Segways and bikes and golf carts and small gas/electric vehicles? They would make great interim transportation while the cities relocalized and perhaps became more dense.