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Re: [EVDL] Converting from watt-hours/mi. to mi/gal & back

--- Peter VanDerWal <[email protected]> wrote:

> Yes but that is ONLY valid for THAT particular ICE
> vs THAT particular EV.
> It says NOTHING about the equivelence between XX mpg
> of gasoline vs ZZZ wh
> per mile of electricity, except between THOSE
> vehicles.

Which is exactly the issue when you compare any two
vehicles, ICE or not. If I make a comparison between
my car and my truck that is exactly what I'm
comparing, not my neighbor's SUV. My understanding of
the OP was a comparison of his car as an ICE to after
its conversion to an EV, nothing else.

> You can't get a generic XX equals ZZZ, except as a
> very rough
> approximation that's only 'sort of' accurate most
> (but not all) of the
> time.

At some point a common "thing" has to be used for some
comparisons. Energy is one such item. Sometimes the
common "thing" is a money standard.

> It gets worse when you start taking into account
> where you measure the
> elctricity at, the controller, the wall, the power
> plant, the...

It depends on what you want to compare. If you are
going to do a wells-to-wheels comparison then both
paths have to be compared in their entirety.

> Lots of folks post wh per mile figures, but neglect
> to tell you where they
> measured them or how they measured them.

That is true, however, as I understood the topic in
this thread, and what I was saying earlier, the
comparison was with what was put into the ICE tank and
what came out of the wall into the EV. In this case
the efficiencies of each of the energy converting
devices are appropriately and automatically taken into
account, as they should be.

If these efficiencies are to be ignored then for the
same shape, speed, mass, trip, resistances, etc. the
energy will always be identical. Simple laws of
physics.

> >
> >
--- Peter VanDerWal <[email protected]> wrote:
> >
> >> It's not that easy.
> >>
> >> It's not a this equals that formula.
> >>
> >> You have to take into account the efficiency of
> the
> >> ICE and the efficiency
> >> of the EV drive system.
> >
> > But if you measure what you put into the vehicle
> the
> > efficiencies are automatically taken into account.
> If
> > one is wondering about fuel/energy cost per mile
> then
> > use your cost of electricity and compare it to the
> > cost of gas. Naturally each will convert to a
> > different miles per gallon figure.
> >
> >>
> >>
> >> > Guys, what am I missing.
> >> > I know my old Civvy got 32 mpg.
> >> > I know CivicWithACord gets 300 wh/mi. maximum.
> >> >
> >> > Now I need to know the equivalent watts or
> joules
> >> in a
> >> > gallon of gasoline, and I should be able to
> >> convert.
> >> >
> >> > Appreciatively,
> >> >
> >> > Converting a gen. 5 Honda Civic? For $20 DVD
> you
> >> can purchase footage of
> >> > my '92 sedan, as well as a del Sol and hatch
> too!
> >> > Learn more at:
> >> www.budget.net/~bbath/CivicWithACord.html
> >> ____
> >> > __/__|__\ __
> >> > =D-------/ - - \
> >> > 'O'-----'O'-'
> >> > Would you still drive your car if the tailpipe
> >> came out of the steering
> >> > wheel? Are you saving any gas for your kids?
> >> >
> >> >

David D. Nelson
[email protected]

http://www.austinev.org/evalbum/1328


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