I was doing some back of the envelope on a plug in hybrid car a few days 
ago. Assuming you need about 15KW to cover you average daily drive 
(about 1 hour on the highway so say about 100km range, at lower speeds 
150 or so would be a likley figure). The best batteries at the moment 
are lithium nano phosphate cells exemplified by the A123 companies M1 
cells (as used by dewalt 36v power tools). Currently i can get those off 
ebay for around $10 per cell, or $8 if i'm picky. That is by purchasing 
pre-built DeWalt packs and splitting them for the cells. Each cell has a 
voltage of 3.2 volts and will supply 2.2AH of current. Roughly speaking 
7 watts per battery. Ergo you need about 2200 cells (this is on par with 
the Tesla roadster which has a similar specced range so I feel I'm in 
the ballpark). Assuming you can get the cells for $8 per cell thats 
$17600 worth of batteries. On average an Australian will drive 25000KM 
per year. Assuming the average car gets 8 liters per 100km traveled 
(which is a fairly efficient car) they will use about 2000 liters of 
fuel. At $1.50 per liter that is $3000 per year. Electricity cost here 
is 14 cents per KWh peak and about 6c off peak. Therefore a 15KW charge 
will cost you $2.1 (Plus a bit of margin). If we assume conservatively 
you have used this to drive at 100KM/H for 1 HR it costs you $0.021 per 
KM. Over a year that is $525 at peak rates. Charging off peak you get 
$0.9 for a charge and $225 per year.

This is on batteries alone but they are the most expensive single 
component and the most likely to need replacement.
Payback period charging at off peak rates is.
$3000 - $225 = $2775 per year that electric is cheaper.
$17600 / $2775 = 6.3 years.

Assuming you spend an additional $8000 on other gear for the car 
(chargers, speed controllers, motors, new wiring, 12KW generator etc) 
you still pay for the electric mods in 9 years on fuel savings alone. If 
you factor in scheduled services, maintenance etc you shorten this 
period by a decent amount.




James Newton wrote:
> Hey Mike, 
>
> Yes, you do know what I'll say, but I wanted to chime in on a couple of
> related points:
>
> First, I'm really impressed with the way everyone has responded to this
> thread. It's one of the better discussions we have had. The use of
> references to back up statements of fact is just totally cool.
>
> One thing that sort of surprises me is that no one presented total cost of
> ownership and operation figures. In almost every case, sustainability =
> frugality. If it costs less, it does less damage. There are exceptions, but
> that is a very good rule of thumb.
>
> Just to let you know, I just purchased a "new" car a bit ago after the head
> gasket blew on my 91 Honda Civic. The engine is probably reparable in the
> old car and I've put it "up on blocks" while I save my pennies for the
> repair. I paid $4k for it with 139k miles and it now has 230k on it so that
> is around 4 cents a mile. It got about 32mpg gas with gas at between $2 and
> $3 per gallon during it's life, it cost me about 8 cents a mile to operate
> gas wise... Add another few cents a mile for repairs and so on and the total
> cost of ownership and operation is around 14 cents a mile. It's now worth
> about $0 but with a rebuilt engine (cost $1k) it should be worth around
> $1.5k or $2k. I won't bother to take that off the cost; $14 cents a mile is
> darn good.
>
> In the mean time my wife and I did a LOT of looking around and researching
> cars and eventually settled on a 2001 Toyota Camery. It only gets about
> 27mpg, and it is sort of a boat. But with 90k miles on the odometer, I
> expect to be driving it for a long time.  If it lives as well as the Civic,
> it will die around 2017 at about 240k miles and having paid about $10k for
> it and gotten 150k miles, it will have cost me 7 cents a mile to own. Given
> the higher gas prices (I'm assuming it will average $5/gal over the next
> several years) and lower mileage, with a few repairs, it will probably cost
> 20 cents a mile to operate. That totals out to 27 cents a mile, or about
> double the cost of the Civic. 
>
> So why would I double my cost and therefore impact the planet twice as much
> as I could have? 
>
> Because it has a much better crash rating than the Civic. And more than
> 60,000 people die on the US roads every year. 
> http://techref.massmind.org/techref/other/911.htm
>
> "What price the crown of a king on his throne, when you're chained in the
> dark all alone?" (Extra points for naming the song.)
>
> And I still haven't managed to pull off being able to work from home or at
> least very near home. If I do, the wife can drive it and we can sell her Van
> (don't buy the '98 Odyssey! Any other year is fine.) and I will get a little
> solar recharging electric NEV
> http://www.sunvee.com/ or at least something small
> http://techref.massmind.org/techref/other/cars.htm and stay away from the
> freeways.
>
> If I could have found a diesel with as good a reliability rating (the VW's
> are NOT reliable) in our state, and a good crash test rating, I would have
> gone with that and tried to do a veggie conversion. There are 24 small
> restaurants in walking distance of my house. But I probably wouldn't have
> actually done it, and I was concerned about other people beating me out for
> the oil in the future. If I can find something interesting, I still might
> trade in the Camery. I spend about $2500 on gas each year so that adds up to
> a solid $12500 in just 5 years. I could invest $20k in a truck and break
> even pretty quick if I felt better about scavenging oil. 11 mpg * $0 per gal
> = donut cost of operation.
>
> A Prius would have cost around 15 cents a mile to operate and something like
> 14 cents a mile to own. At 29 cents a mile it is actually worse, but that is
> based on VERY rough numbers which are hard to smooth due to the newness of
> the technology.
>
> Has anyone else actually run the numbers? Did you come up with something
> different?
>
> --
> James.
>
>
>
>
>
>
> -----Original Message-----
> From: piclist-bounces@mit.edu [mailto:piclist-bounces@mit.edu] On Behalf Of
> Mike Hord
> Sent: Tuesday, November 27, 2007 10:03
> To: Microcontroller discussion list - Public.
> Subject: [OT] Car purchase
>
> James, I already know what you'll say.
>
> My fiance and I are looking at buying a car.  We both drive sub-optimal
> autos
> (2003 Jetta GLI for me, 2005 Chevy Malibu for her) and we want to can them
> both.  I bus it to work everyday day, and she drives 5 miles across town.
> We
> rarely take trips longer than 10 miles.
>
> She owes more on her car than it's worth, but mine is paid off.  We want
> both
> a fiscal and environmental sustainability upgrade here- meaning we want to
> pay less for gas and car payment and insurance, AND we don't want to be
> contributing to the worsening environmental situation.  We also don't want
> to
> be stuck with a car that's going to require huge repair bills annually.
>
> We're leaning towards a new or slightly used Prius or a new Yaris.  I hate
> the
> idea of a new car because new cars are part of the problem- building a car
> takes a lot of energy.  OTOH, if we keep the car for ten years, it makes
> sense to get a new one.
>
> At any rate, someone on this list has a resource that they can point me to
> that will help me gauge the relative impact of these choices.  I'm totally
> lost.
>
> Greenercars.org seems good to me, but they completely ignore the used
> car option....
>
> Mike H.
>   

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