Aptera diesel-electric hybrid car gets 300 miles per gallon and will cost $29k.

How can it take 10.444 kW to move a car at 50 mph but only 200 w/hr to
move a car at 50 mph? Remember that a w/hr is a unit of power for a
period of time. A watt is a unit of power without reference to time.

You could use any battery voltage you wish. I chose 100 volts to make
the math easier to follow. The battery voltage would have no effect
on the power requirement.

It IS the amps and the voltage and the current and the wattage. They
are all related. Power in watts is voltage time current. Yes, you
could use a 1000 volt battery and it would only require a current draw
of 10.4 amps. The power would be the same.

You still have to put the power used back into the battery regardless
of what voltage you use to power the charger or what type of battery
you use.

What about the poor guy who has to travel 1000 miles in his electric
car. Does he drive 200 miles then stop for 8 hours while the battery
is recharged?

Jack

 

So 4 hp would move the car 16 miles in an hour (16 mph). A 8 hp motor
would move the car 32 miles. A 16 hp motor would move the car 64
miles. And it would take a 32 hp motor to move the car 128 mph. Holly
smokes, my car should be able to travel at well over 400 mph using its
120 hp motor. Do you see something wrong with this progression?

A watt is a unit of power without regard to time. A wHr is a unit of
work. 10 watts isn't the same as 100 watts but 10 watts applied to a
device for 10 hours will do the same amount of work as 100 watts
applied for 1 hour. The same is true of horsepower, it's a
measurement of power not work. A hpHr is a measurement of work.

So, if it takes 14 hp to move a car at 50 mph without regard to time.
It will take 14 hp to move that car at 50 mph for one minute or one
hour. The only difference is the amount of work done, not the amount
of power needed.

So, his figure of 200 watts to move a car at 50 mph is wrong.

Jack

 

Would you prefer if we said that it takes 10.444 kWh to move a car
50 miles in one hour? How about that it takes 1/50th of that to move
the car just 1/50th of that distance in 1/50th of that time?

I'll let you do the math. Hint. 1/50th of 50 miles is 1 mile.
(I'll let someone else describe w/hr and Whr differences.)

The wiring in most houses is limited in amperage. Say your car can
only draw 30A from the outlet. If the outlet is 220V then it can get
twice the power than it could if it was 120V. A car that would need
8 hours to recharge on 120V would only need 4 hours on 220V.

Your complaint seems to be that it would take too long to recharge a
car at 120V. I suggest that it wouldn't take too long at 220V.

What about the poor guy who has to travel 4000 miles? What does he
do for speeding tickets and sleep?

Around these parts, it would take over 18 hours to drive 1000 miles
and anyone who has to drive more than a 1000 miles a day has got bigger
problems than where to plug in his car.

Assuming your car gets some 5 miles/kWh and you get to recharge using a
typical 220V 30A outlet. It would only require 6 hours of recharging for
every 200 miles of driving (more or less). This sounds reasonable to me.

Some folks have been suggesting the use of 'quick charge' outlets that
provide higher voltage, current or both. These could recharge the car
while eating lunch (or dinner).

Anthony

 

That number should be 500miles per day...at least if the driver wants to
stay
legel and safe.Roughly what a solo truck driver does in a day.
But then that also begs to explain as well ,if electric power is cheaper to
operate.And can do the the range across country without delay,with the
potential
of savings for the driver.Why are we starting out with cars instead of
battery powered trains
and 18wheelers?Hell the trains in most of the country already have thier
600v computer controled
traction motor already installed.Now how many of them everlasting batteries
do we for a 6000hp
locomotive.They sometime run more than one locomotive in a consist.....but I
guess we can multiple that one locomotive number on whatever the consist
requires.
At the same ,time I remember some trains were striaght electric.You think
,there might be a reason for most to run diesel on a generator,instead of
electric off an overhead or batteries.

 

Try getting off peak power. Plug it in and let it charge while you
sleep for about half the cost of daytime power. What makes you think
the $/mi should be the same as for gasoline?

 

To maintain a speed of 50 mph it takes 10.444 KW (note KW not KWhr).
If you travel at 50 mph for one hour you will have gone 50 miles and
you will have drawn 10.444 KW for one hour, meaning you used 10.444
KWhr. To only travel one mile would only take 1/50=.02 hrs. If you
draw 10.444 KW for .02 hr then you used 10.444*.02=.20888 KWhr or
208.88 watt-hours.

Your complaint seemed to be about the high current draw. Using a
higher voltage reduces the current. And actually it does have an
effect on the power requirement. Part of the power requirement is
providing for power losses due to resistance heating in the batteries,
wiring and motors. Those heat losses are proportional to the square
of the current. Go from 100V to 200V and the resistance losses are
cut to 1/4 of what they were. That also means you can work the motor
harder without over heating it.

Take his other car? Take the bus? Rent another car?
The electric may not be able to do all things, but if it can get the
equivelent of 160 mpg or more for the vast majority of your traveling
then maybe you can afford to make other arangements for those trips
that it isn't suitable for.

Another possibility would be to have an engine just big enough to
provide the power needed for a steady state cruise at the highest
speed you need to go. When going slower the batteries could be
charged on the fly so there would be more power availible for
acceleration or climbing hills. Something like this

http://tinyurl.com/22d3n6

should let you cruise at 70 mph while using .9 gal/hr. That works out
to 77 mpg.

Bruce

 

Sure, I made it linear rather than exponential to keep things simple.
The further you get from the 50 mph starting point the further off you
will be. The point was that 1/4 hp would move the car 1 mile in an
hour. That's traveling 1mph for an hour.

It was 200 watt-hours to move the car one mile in 1/50 hrs. If you
want to go 50 miles in an hour it will take 50 times that.

 

I give up. You folks seem to be unable to understand that there is a
difference between power and work.

Jack

 

Sorry but you're the one that seems to have things mixed up.

If you apply a force over a distance you have work. Say you push with
a force of 11 pounds for a distance of 50 feet , you have done 550
foot pounds of work. Time doesn't enter into it. It is 550 foot
pounds of work whether you do it in ten seconds or ten minutes.

Power is how much work is done in a given time. 550 foot pounds per
second is one horsepower. So if we pushed the object above the 50
feet in one second it would have been 1 hp. But it took 10 times that
long so we were producing .1 hp.

Watts are power. 1 hp = 746 watts.

If we specify a power output for a specific period of time the result
is an answer in work. Look at the units. Power is foot pounds
divided time, and you are multiplying by time. The times cancel out
leaving you with foot pounds.

The same thing applies to watts. A watt is current times voltage.
The current is flow per unit of time. So when you specify a time
period for those watts you multiply by that time and get the work done
during that time.

In the original example we knew it took 10,000 watts to maintain a
speed of 50 mph. We know that at that speed it takes .02 hours to
cover 1 mile. Multiply the power (10,000 watts) by the time (.02
hours) and you get an answer in units of work (watt hours). If we had
multiplied the power in horsepower by the time we would have gotten an
answer in horsepower hours which can be converted into foot pounds.

The 200 watt hours seems like a small number compared to 10 KW, but it
is the work done in a short period of time (.02 hours). If you do the
same thing 50 times it will take 200*50=10,000 watt hours over a
period of 1 hour. Or go at it the other way around. Divide 200 watt
hours by .02 hours. The time units cancel out leaving 10,000 watts.

Starting to make sense?

Bruce

 

200 empg might get our attention, and 100 empg would be entirely
believable of what a 4 seat diesel/electric hybrid shouldn't have any
problems accomplishing while cruising along at 60+ mph with a one
liter turbocharged diesel+electric hybrid, having an ideal city
driving capability of 200 empg being somewhat iffy, especially for
under $30k.

A true multi-fuel hybrid could accomplish a typical 6-passenger SUV at
200 empg city and easily 100 empg sustained at 60+ mph, all at the
absolute minimum of CO2 and zilch/zero NOx. (we accomplish this nifty
feat by simply replacing our polluted atmosphere of mostly N2 with
instead injecting h2o2)
- Brad Guth -

 

Aptera has also eliminated one of the remaining aerodynamic obstacles
found on conventional cars -- the side-view mirrors. They have
replaced them with a camera and a dashboard monitor. The lack of side-
view mirrors probably wouldn't be street-legal on a car in the United
States. However, in the United States, a three-wheeled vehicle is,
legally speaking, not a car -- it is a motorcycle.


+-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-+
| Ladasky Home Solar, Inc.: blowing sunshine up your |
| power grid since March 24, 2005. Fiat lux! |
+-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-+
| Uptime Downtime kWh generated kWh consumed |
| 939.4 days 14 hours 17188 17532 |
+-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-+

 

Mirrors are covered by state laws. I know that in my state (NH) an
inside mirror alone will get you through inspection. Outside mirrors
are required for vehicles where an inside rear view is blocked. I
haven't checked but I suspect that the camera set-up would be ok
without side mirrors in NH.

Bruce

 

That's very true, as not even the VW LUPO that could actually obtain a
sustained 100 empg under ideal conditions never got in, and I'm not
certain the VW Fox was any better off, but at least the Aptera diesel-
electric that's suggesting 300 empg at 20 mph (down-wind) kind of 2-
person clown-car option/scam, whereas in some of our grid-lock city
environments (like NYC) you can't hardly average but 10 mph, so it
could work as is, especially if it were a one cylinder 0.1 liter
diesel engine that's somehow micro turbocharged and running one heck
of a flywheel/alternator at 7,200 rpm, if not faster.

Aptera diesel-electric hybrid; following link comes with lots of
absolutely stupid graphics, spyware and butt loads of those crapolla
infomercial advertisings
http://www.treehugger.com/files/2007/03/the_future_is_h.php

By the time it meets crash safety and many other essential standards,
it will not get much better than half of their projected empg, and
there's no such thing as HVAC.
- Brad Guth -