Yes, m*g*h is appropriate. I'm not sure how much difference air density
will make, but that's part of the formula, too. Basically, you figure
your areo drag on the level, add in any efficiency losses, and add the
force necessary to climb. Other factors would be acceleration from a
start and deceleration (hard to do) and other speed and slope variations
but I don't think they'll even make 1% difference.
Here's the drag formula, which include air density, from an email
severaal days ago. To convert that to energy, multiply the result times
distance, in other words w (work) = f * d.
1/2 * Cd * A * air density * speed^2
where
Cd == drag coefficient (you can look this up for many car models)
A == frontal area: the area of the vehicle as viewed in 2D from the
front, in meters^2
air density = roughly 1.2 kg/m^3 at standard temperature and pressure.
speed: in meters/second
will give you the resistance (i.e. force) in N (newtons).
Peri
------ Original Message ------
From: "Peter Eckhoff via EV" <[email protected]>
To: "Zeke Yewdall" <[email protected]>; "Electric Vehicle Discussion
List" <[email protected]>
Sent: 03-Aug-14 5:56:33 PM
Subject: Re: [EVDL] As an aid when recommending an EV to someone else,
Hi Zeke,
When I joined this list about 10 years ago, there is an expression
concerning EVs that "hills kill" in reference to the fact that a lot
more kwhrs are expended going up and down hill than on the flat. For
that reason, talk of driving an EV in mountainous or even very hilly
areas was almost non existent. The main problem for us was starting
uphill from a dead stop with a DC motor.
Now we have Teslas going cross country. A high school classmate said
she saw a Tesla at Breckenridge and I don't doubt her one bit. I assume
that person did not have it transported there but drove it up from one
of the big cities along the Front Range. Heck, they could have driven
it in from the east or west coast.
As a question to the List, is there a way to calculate how many kwhrs
it would take to go from Boulder (5430' MSL) or Fort Collins (4982'
MSL) to Estes Park(38 & 42 miles, respectively (7522' MSL), CO? And
from Estes Park (7522' MSL, to the Alpine Visitor Center, Rocky
Mountain NP (24 miles, max elev.: 12,200'MSL); almost a mile - 500 feet
in the vertical.
Would the old potential energy formula of Energy (kwhrs) = m*g*h (mass,
gravity, and height) work?
At lower altitudes near sea level, I assume that more energy is
expended per foot of altitude change due to more air resistance so a
climb from Old Fort (1450' MSL), NC to Asheville, NC (24.2 miles)
(2300' MSL at top of the pass leading into Asheville) would require
more energy than at the same speed and distance going up into the Rocky
Mountains.
Has anyone noticed the attitute sea change? Before the Tesla, we might
not have bothered with this question. Now it is something to discuss
because it **has** happened and can **easily** happen again.
EV discussions on driving in mountains has arrived!!
On 8/3/2014 9:33 AM, Zeke Yewdall via EV wrote:
good point Roland. Living 11 miles from the closest gas station as I
do,
with most of them at least 25 miles away, there have been days where I
did
not have sufficient gas in my car to do a 40 mile trip (20 miles each
way,
the other direction from the gas station), and had to turn it into a
62
mile trip -- going the opposite direction to get gas, first, then
doing the
trip. An EV would have been able to charge at the house and ready to
go in
any direction from it.
As a side note, I'm seeing more and more leaf's up in the mountains,
where
people never used to take EV's (we're a 4,000 foot climb above
Boulder).
I've seen them up at campgrounds up in the mountains and in Rocky
Mountain
National Park and all kinds of places. Not just inside the metro area
any
more.
Z
On Sun, Aug 3, 2014 at 7:30 AM, Roland via EV <[email protected]>
wrote:
One more thing you can add in range comparison between a EV and a ICE
is:
I was ask what is the range of my electric, I said it may have the
same
range of a ICE some of the time and more at other times.
The EV has the same maximum range every day, because I charge it once
a
day or after each trip. Some ICE's do not have that maximum range
daily,
because they may only fill up once every two weeks or once a month.
Thus the convenient of filling up the EV at home may only take 3.5
minutes
to charge.
Roland
----- Original Message -----
From: Dennis Miles via EV<mailto:[email protected]>
To: EVDL Administrator<mailto:[email protected]> ; Electric Vehicle
Discussion List<mailto:[email protected]>
Sent: Saturday, August 02, 2014 11:44 PM
Subject: [EVDL] As an aid when recommending an EV to someone else,
One question that a potential EV car buyer always asks is "Just
how far
it
will take me before another charge is needed? "
Perhaps we should have another computation available, as
comparison,
for each vehicle:
Cost to drive 40 miles (Average daily commute.) (Dollars per
mile.)
Time to drive 1,000 miles?
Cost for all fuel consumed?
Time to drive 2,000 miles ?
Cost?
Time to drive 3,000 miles ?
Cost?
Distance drivable in eight hours?
Cost?
Distance drivable in 16 hours ?
Cost ?
Footnote: assuming 65 mph average speed and stops as needed for
charging
or
refueling.
Not including driver's breaks for food and "necessary" stops...
Dennis Lee Miles
(*[email protected]<mailto:*[email protected]>
<[email protected]<mailto:[email protected]>>)*
* Founder: **EV Tech. Institute Inc.*
*Phone #* *(863) 944-9913 (12 noon to 12 midnight Eastern US
Time)*
*Educating yourself, does not mean you were **stupid; it means,
you are
intelligent enough, **to know, that there is plenty left to
learn!*
* You Tube Video link: http://youtu.be/T-FVjMRVLss<
http://youtu.be/T-FVjMRVLss>
<http://youtu.be/T-FVjMRVLss<http://youtu.be/T-FVjMRVLss>> *
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