My Biggest, Baddest Rant - triple digit mileage

[atgcpaul]

What comes to mind for me is converting everything from "miles per gallon (of gasoline)" to "mile per universal unit of energy". For instance, you could easily convert both kWh and gasoline to BTU's. Of course that's an antiquated english measure of energy...but then again so is miles AND gallon so it would fit right in.

Anyway that would be a way to compare apples to apples going from conventional full gas cars all the way to complete electric cars.

My thoughts exactly. People know how much a gallon of gas costs them so
that's why MPG is universal. If they want to stick with MPG, then someone
(probably has) should come up with (and include all the inefficiencies)

charging my car with X size battery for Y amount of time = Z gallons of gas

Then factor Z into the stated MPG, then you've got a better number.

Paul

[JR]

The problem here is that there are two cost profiles to work with - electric power and gas/diesel - and they must be aggregated. Electricity is largely regulated, but now has tiered pricing. Gas prices are are largely unregulated, so cost is an unknown. Ttoal cost will be a function of the user's overall consumption.

You could have single measure of energy consumed, perhaps a sort of carbon footprint measurement. I don't think this would be very informative, though.

If you're going to use two forms of power you'll have to measure both forms separately for it to be meaningful. You could follow the method in use now, adding the new measurement. So a city performance measurement would show two values, one for the rate of electricity consumed and one for gas. Same for highway. These values might be amp-hours and mpg. These could be shown as something like this (making up some values):
City = 14aH/230mpg
Highway = 8aH/120mpg

<<<
edit: I think people would quickly learn how to interpret the numbers. In fact, looking at it now I can see that a siingle value can be derived from this information. A high gas number divided by a low electricity number would result in a single value that would be meaningful. The underlying values would still have to be displayed so that consumers could make an informed choice as to fuel choice. So the display might look something like.

City = 14aH/230mpg = 16.4 efficiency value
Highway = 8aH/120mpg = 15 efficiency value
>>>

I suppose you could then use pro-forma costs for each form of energy to make the total cost analysis.

JR

[Alex Franke]

While I understand & agree with your point that the type of fuel used is important to consumers, Loring is dead on here. Claiming 230mpg for what is primarily an electric car is misleading at best, some might call it fraudulent.

I think we all agree that using MPG alone to convey energy consumed for an electric car is wrong. My point is that it is a perfectly valid measurement of the gasoline consumed, and that to some people (probably the target demographic in particular) that is more important than the total energy consumed.

For example, I might be able to make a nice little bookshelf with 50 bf of figured maple per unit. But if I use this newfangled hybrid (laminated plywood) I can get that down to 15 bf/unit for essentially the same thing. That doesn't mean I'm using less material, it just means I'm using less of my prized figured maple.

In the context of "how must gasoline does the car consume" I think MPG is perfectly appropriate so long as there's a big asterisk by it. In the context of "how much energy does it consume, or what will it cost me to operate it", I think MPG alone is clearly not appropriate and, as you suggest, possibly fraudulent.

I don't know for sure, but my guess is that the target demographic for these cars is probably more educated about where their energy comes from than for traditional cars. For example, I have a friend who is a perfect candidate -- he lives in South Carolina partly because half their energy is nuclear, and the other half comes from domestic coal. He'll be happy to pay probably up to $20k more for a car that uses less gas even if it only saves him 10% of that in energy cost because he doesn't want to feel like all his money is going overseas. (Note: I'm not suggesting we debate the validity of this example.) Most people don't even know where their energy comes from, but he's a little more educated on this front and loves to be able to say "I get X MPG" -- he's not saying "I use less energy" or "I pay less to operate my car" but rather, "I use less gasoline and that makes me happy."

Another shocker for a lot of consumers is gonna be when they buy one of these and find out it needs something like a 220V 50A connector in their garage to charge it.

I don't think charging at home is the solution at least until homes can move the type of current required for quickly charge a bunch of cells. I think more likely you'll see places like grocery stores getting into the business. Park your car, plug it in, do your shopping, and pay for the energy you've used when you check out.

[lrogers]

The part that dropped me to the floor was the $40K price tag!

[Jim Frye]

I am not an Engineer,

but I did stay in a Holiday Inn Express once.

Loring is spot on with his arguments (rants). Until we get a common method of measurement of motor vehicle's operating costs, the MPG measurement is now obsolete. I saw the GM 23(NEMA 15R) ad two days ago on TV and just sat there with my jaw in my lap. I am a car nut and have been following the Volt (and others) saga for some time now and that ad just made no sense, except for an obvious attention getter. I have seen claims from GM in the past that it would cost you $4.00 to charge the Volt at home. The Toledo Blade had an article on the Volt in today's paper and they attempted to put the cost into perspective for a local resident. There is a HUGE "IF" attached to this analysis, but here it is.

"Based on the rating - and on First Energy's current 12 cents per kilowatt hour average residential rate - a Volt owner would pay $6.00 a week to commute 20 miles each way to work; compared to $10.75 for the owner of a Toyota Prius, the world's top-selling hybrid car. The owner of Jeep Wrangler (built here in Toledo & rated at 15 mpg), ... would pay $34.40 for fuel at $2.58 a gallon ... to commute the same distance."

I drive a '97 Honda Civic EX that gets 30 mpg in town on that 20 mile commute, so my gas cost should be about $17.20.

The "IFs" here are cost of gasoline, electricity, and the milage driven each day, and how will they vary over the life of your ownership. The Volt battery pack is good for "approximately" 40 miles of gasoline free driving. How long will the pack maintain that range over the years? The pack is supposedly good for over 100,000 miles, but.... What is the battery pack replacement cost?

My electric rate is going to drop from the nearly 12 cents per KWH to 7.8 cents per KWH due to a lock in contract good until 2011. That makes the Volt, or any other plug in more attractive. My '97 Civic and '03 Protege5 will both last several more years, so I get to sit on the sidelines watching this show and not having to try to justify making a purchase (or better yet, lease) decision. One other thought: After over four decades of driving, I have learned to never purchase a first year GM production model. I'd wait for Volt v.2 to roll off the assembly lines before considering opening my wallet for a Volt.

[Tom Slick]

I calc'd it out one time and a $40k volt does break even with a $30k car before the 5 years of payments are over when you take into account routine maintenance on regular a gas powered vehicle. unfortunately I can't find my spreadsheet though.

If you electricity is billed time of use (TOU) there are some additional savings to the average $.12.

edit:

I found it! there are some assumptions such as $3.70/gal gas and 100 miles/day commute.

Tossing out some numbers
60 month loan at 7% interest
payments:
$30,000 = $594 per month, $7,128 per year
$40,000 = $792 per month, $9,504 per year

difference = $198 per month, $2,376 per year

$30k car gets 30 mph and the daily commute is 100 miles round trip 20 days a month
gas costs $3.70/gal
gas = $247 per month, $2,964 per year

Oil changes every 5,000 miles = 4.8 per year
at $30 per change = $12 per month, $144 per year

for simplicity, leave off air filter, fuel filter, coolant, other longer duration, low cost maintenance items unique to internal combustion engines.

Total cost of driving $30k gas vehicle:
$853 per month, $10,236 per year

at the break even point, it leaves $61 per month, $732 per year, to pay for electricity to charge your $40k electric vehicle.


I have no idea how much power these cars demand for charging and of course these numbers are a bit simplified because there are other cost of ownership items but I think it shows that even paying a significant premium for an EV the overall costs could be similar to a less expensive IC powered car.

[LinuxRandal]

I calc'd it out one time and a $40k volt does break even with a $30k car before the 5 years of payments are over when you take into account routine maintenance on regular a gas powered vehicle. unfortunately I can't find my spreadsheet though.

If you electricity is billed time of use (TOU) there are some additional savings to the average $.12.

edit:

I found it! there are some assumptions such as $3.70/gal gas and 100 miles/day commute.

Tossing out some numbers
60 month loan at 7% interest
payments:
$30,000 = $594 per month, $7,128 per year
$40,000 = $792 per month, $9,504 per year

difference = $198 per month, $2,376 per year

$30k car gets 30 mph and the daily commute is 100 miles round trip 20 days a month
gas costs $3.70/gal
gas = $247 per month, $2,964 per year

Oil changes every 5,000 miles = 4.8 per year
at $30 per change = $12 per month, $144 per year

for simplicity, leave off air filter, fuel filter, coolant, other longer duration, low cost maintenance items unique to internal combustion engines.

Total cost of driving $30k gas vehicle:
$853 per month, $10,236 per year

at the break even point, it leaves $61 per month, $732 per year, to pay for electricity to charge your $40k electric vehicle.


I have no idea how much power these cars demand for charging and of course these numbers are a bit simplified because there are other cost of ownership items but I think it shows that even paying a significant premium for an EV the overall costs could be similar to a less expensive IC powered car.

The problem with above, is the Volt isn't a strictly electric (currently) vehicle, like the Aptera (who also designed in aerodynamics to reduce energy use). It is a hybrid, with the same maintainance costs of oil, filters, etc.

[LCHIEN]

...
I have no idea how much power these cars demand for charging and of course these numbers are a bit simplified because there are other cost of ownership items but I think it shows that even paying a significant premium for an EV the overall costs could be similar to a less expensive IC powered car.

the article quotes GM as saying 25 KWH per 100 miles.
Continuing with your calculations,

the electric car for 20 days of 100 mile commutes will use 500 KWH
at .17 per KWH (since you chose a rather high gasoline figure of 3.70 per gallon I chose a higher end electric figure to match) will cost $85 per month. Rather higher than the $61 you said was the break even point.
I also think there's a hidden cost, the battery life will be no more than 5 years, maybe only 3 years. and a battery large enough to power a fully electric car 100 miles per day will be rather large and hence expensive. Several thousand dollars for replacement. Lets assume 5 years and $3000 then the added cost for battery amortization will be $600 per year or an additional $50 per year.

Between the $50 battery amortization and the $85 for electricity per month your figures are not looking good for the EV. Unless you get a government rebate of maybe $5000-6000.

[Alex Franke]

The problem with above, is the Volt isn't a strictly electric (currently) vehicle, like the Aptera (who also designed in aerodynamics to reduce energy use). It is a hybrid, with the same maintainance costs of oil, filters, etc.

hmm... That actually brings up an interesting question. They say it "can drive up to 40 miles a day without a drop of gas." If you mainly drive in town so that the engine rarely kicks in, how often to you change the oil?

[Tom Slick]

When I made those calcs last year, GM was claiming 40-50 miles on a charge, so according to them I *could* make a trip to work, charge, and drive home, with no engine assistance.

Because of reduced engine usage oil changes would be reduced to maybe once a year.

Other hybrid vehicles have been around much longer than 5 years with the original batteries, of course the volt's battery life is TBD. The Prius is becomming proven technology.

It can cost more, my point with tossing some numbers out is that it isn't that much more than a comparable car, which is what many people think.

I'm not trying to defend these vehicles, I currently drive the antithesis at 15.5 mpg, but they are becomming closer to a benefit. Right now they are in the early adopter/ "feels good" stage of buyers.

[LCHIEN]

hmm... That actually brings up an interesting question. They say it "can drive up to 40 miles a day without a drop of gas." If you mainly drive in town so that the engine rarely kicks in, how often to you change the oil?

If you don't drive your regular gasoline engine car at all or just minimal mileage you still should change the oil every season (which I take to mean every 6 months but some could interpret that as 3 months) according to virtually all manufacturers. I assume this is replace the oil which builds up acidic compounds* from combustion gasses that combine with the oil, and breakdown of the long oil hydrocarbon chains from heat and time.

*Gasoline has some trace amounts of sulfur, so SO2, also CO and CO2 and NO2 and NO3 are in exhuast gasses to some small extent. these combine with water (another product of combustion) to make up carbonic acid, nitric acids and sulfuric acids in small amounts that may get absorbed into the oil and thus eat at your engine from the insides. Not much but enough you may want to change your oil periodically to prevent build up and internal corrosion.

Of course one could say the oil is already millions of years old, how can it go bad in one season?

[LCHIEN]

We sat around after the news tonight and were saying the same thing. Need real numbers to make real comparisons of cost differences. How much money per mile would I be spending gas vs electricity.
Something else I wonder. Does it retain the charge if you "fill er up" and then don't drive it for a couple of days (nice weather and I'm going to the topless Jeep ) is it still "full" like a gas engine is?

Some battery formulations are better than others at storing charge, they all have something called internal leakage or self discharge which means that left alone they will eventually go to a state of zero charge (e.g. empty). The charge leaks off exponentially so after N days it would have half charge, and N more days it would have 1/4 charge, and after N more days it would have 1/8th charge left. Temperature has a great effect on leakage rates, as well (hot - worse, cold - better which is why some people store unused batteries in the fridge)

Lead acid batteries can hold charges for weeks and even months before losing half the charge, but because of their weight they are not finding favor in hybrid or all-electric cars.

Lithium cells are usually pretty good about holding charge, they don't tend to discharge very rapidly BUT there are many flavors of lithium-based cells so that's a generalization - I would think it would be weeks or months before half charge leaked off like lead acid cells, or even longer. Because they are light per watt-hour, they are the most favored electric car battery.

Other batteries, like Nickel Cadmium are notoriously bad leakers, losing half charge in a couple of weeks. Fortunately these have not found use in cars.

NIckel-Metal Hydrides are between NiCad and Lithium in leakage and do find some use in car batteries, being chepaer than lithium but weighing more.

Non-rechargeable batteries, like primary lithium, or Alkaline cells, have half-charge loss times measured in years, but you can only use them once.

So the short answer is, for most EV's and hybrids, a couple of days is no problem at all. A couple of months and you may lose a significant fraction of the stored power - GM is claiming a 40 mile battery only range and about .25 KWH for 1 mile so a full charge is 10 KWH which is around $2 at 20 cents per KWH, so having it leak off from non-use is not a financial disaster but you could find a significantly shorter battery-only range after some non-use. 40 miles of gasoline for my 20 MPG car is 2 gallons or around $5 at todays prices.

[gsmittle]

It's much more transparent for the math-challenged in our society (call it 90% of the folks) when you say which will save more going from 0.100GPM to 0.077GPM or going from 0.050GPM to 0.033GPM?

Hey, I resemble that remark!

All of y'all are right, we need some sort of consistent unit to compare these all-electric vehicles to gas/diesel/hybrid/propane vehicles.

I went from a 10 mpg Suburban to an 18 mpg truck. Is that an 80% improvement?

g.

[Jim Frye]

Another Gotcha...

the article quotes GM as saying 25 KWH per 100 miles.
Continuing with your calculations,

the electric car for 20 days of 100 mile commutes will use 500 KWH
at .17 per KWH (since you chose a rather high gasoline figure of 3.70 per gallon I chose a higher end electric figure to match) will cost $85 per month. Rather higher than the $61 you said was the break even point.
I also think there's a hidden cost, the battery life will be no more than 5 years, maybe only 3 years. and a battery large enough to power a fully electric car 100 miles per day will be rather large and hence expensive. Several thousand dollars for replacement. Lets assume 5 years and $3000 then the added cost for battery amortization will be $600 per year or an additional $50 per year.

Between the $50 battery amortization and the $85 for electricity per month your figures are not looking good for the EV. Unless you get a government rebate of maybe $5000-6000.

Back in April of this year, Car and Driver Magazine quoted GM as stating the charging circuitry in the Volt would not charge the battery pack to more than 80% capacity and not allow the pack to go below 30% of its capacity. This was to extend the life of the pack to 150,000 miles at which time the pack would theoretically be down to 50% of its rated capacity. At this time the pack would be swapped out and the owner could use the old pack for some unidentified "green" project in their home or business. I guess the consumer would be responsible for recycling the old pack. I can just see one of these sitting next to the battery recycle box at the local HD!