Hi Peter, John and All,
--- Peter VanDerWal <
evdl@...> wrote:
> > ...
> >>My pickup (far from efficient) uses approx 15kw at
> 60 mph on flat ground.
> >>Figure a bit more in the hills (lots more going
> up, zero kw coming down,
> >>possibly regen if your vehicle has it). A
> reasonably efficient, full
> >> size
> >>EV could easily average 15-20 kw/h at 60 mph.
> >
> > I'm having a little trouble with these numbers.
> The reason I am is
> > that I've done quite a bit of coast-down testing
> over the years using
> > both a GPS-based system and a homemade doppler
> radar-based system.
> > Using 746 watts to the HP, you're talking about
> your pickup truck
> > cruising at 60 mph on 20 hp. My Caprice which is
> much more
> > aerodynamic than a pickup needs 23 hp at 60 mph.
> An old VW bug needs
> > 16. A first generation Datsun Z with 205mm tires
> needs 16 (amazing as
>
> Well, first of all it's a small pickup (87 toyota).
> Secondly it has LRR
> tires and low friction lube in the tranny and diff.
> These make a
> noticable reduction in power requirements.
The lower frontal area and low drag tires really
make a difference of 20-30%. Now if you just put a
Daytona Kitcar, ect body on that frame/EV drive you
would really have something ;-)
>
> FWIW, top speed on my pickup is slightly over 70
> mph. Max power out of my
> batteries (120V worth of 8V GC) is just under 30 kw.
> All power figures
> measured with an E-meter.
I'd bet if you used a good aero camper type shell
like I've described before you could cut that 20%
easily, maybe more. I don't understand why people do
not try these. Even a good normal shell will cut aero
drag 10% as has been proven. And station wagons are
almost always more aero than Sedans. And why mine is a
sportwagon.
>
> > This is power being consumed by the total
> combination of air drag,
> > road friction and all the frictional losses in the
> drivetrain. To
> > convert that back to electrical power, we'd have
> to figure the
> > efficiency of the motor and, depending on where
> the power measurement
> > was made, the controller.
>
> Measured, in my case, between the batteries and the
> controller.
A good place but at the power plug is better though
hard to find a set speed power consumption that way.
>
> > I don't think Li batteries are practical for the
> rest of us without
> > deep pockets.
>
> Maybe not now, but they are getting cheaper fast.
> This hypothetical
> vehicle isn't going to be available for a couple
> years at least, hopefully
> Li batteries will be affordable by then. (Perhaps I
> am the one being
> overly optimistic now)
The basic materials of mag electrode Li-ions are
cheap, we just need for the plants that make them ramp
up so there is competition and many plants are being
built as we speak. So the future looks bright.
>
> > That would be doable at first glance if the weight
> can be handled.
> > BUT. Now there is the issue of continuous
> charge/discharge that Lee
> > mentioned earlier. Can you cool all these
> batteries adequately? How
> > much energy is consumed in that endeavor?
Lee's point on motor overheating is important and
why I went for 2 motors of twice the power I needed so
they could handle long distance higher speed driving.
2 motors have much more surface and brush area and 2
fans for better heat disipation.
>
> Lee has a point, however...we are draining the
> batteries slwoer in this
> case (in say 4 hours instead of 30 mintues to 1
> hour) so they will have
> less heat, also you will have a continuously moving
> airstream to cool them
> while driving. Granted rapid charging them will
> create some heat, but in
If lead and charged at under 80% state of charge,
almost no heat is made from charging, discharging,
especially if you have a gen making most of the power
needed and recharging quickly. Eff approaches 98%!!!
> the short run that just improves their performance.
> Since these long
> trips aren't supposed to be all that frequent, the
> loss in life span is
> small.
Lead batts love to be used as long as they are not
abused and have a longer life in miles, not shorter.
It's batts that sit around not used that die.
>
> Still his other concerns are valid (engine and
> controller heating).
> This is one of the reasons that I'm a proponent for
> parallel hybrid schemes.
But you don't reconize as Lee does the part load
ineff of a parallel system. There is a reason ICE cars
only get 7% of their fuel to the road where EV's get
20% or even 30% with the new Co-gen gas turbine/ steam
generating plants that are 60% eff.
And depending on how you count it, 70% from RE,
wind, Hydro plants!!!
>
> > For all these reasons, a pusher trailer with the
> wheels mechanically
> > connected to the engine makes the most sense to
> me. It can be done
> > cheaply, efficiently and cleanly.
>
> This is a good idea.
Not when cost, weight, part load ineff is counted.
>
> I prefer having the ICE mounted in/on the vehicle
> though for convienence.
> You don't always know when you head off to work if
> you'll need to make a
> long trip in the middle of the day. Going home for
> the trailer might not
> be practical.
> That's why I want to test my idea to see home much
> difference it makes to
> the daily power requirements to lug around the ICE.
And why I want to make my gens under 100lbs or
less than 2 batteries!! How muchwasted energy does it
take to lug 300-500lbs or more instead of 100lbs all
the time? Especially something you need rarely?
>
> >
> > A parallel hybrid setup where the gas engine
> supplies the base motive
> > power for cruise and the electric motor supplies
> acceleration and hill
> > climbing power but no cruise power would seem to
> be the best
> > configuration to me.
>
> I concure.
It's too costly, ineff, heavy for me,
Thanks,
Jerry Dycus
>
>
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