Re: 300 kW EV Tractor vs 400 hp Diesel

Would be a failure as a tractor. One to two hours working time followed
by several hours of recharge time? The Tesla is probably more at than 8
hours of recharge time.

> Running either tractor wide open to work a square mile at 0.5 mph would
> take 3 months of 7 day work weeks at 8 hours / day.

Never drove a tractor, I see. If you are working at 0.5 miles per hour
(about a km per hour), then you are not using anything close to 300 kW..
Soil resistance times speed equals power. I don't know of anything that
would usually be done that slow, but there are crops I know little about,
like cotton and peanuts. More usual speeds are 5 to 20 km per hour, and
that is pulling a disk harrow 6 to 8 meters wide or wider, and working 20
cm deep. Planting takes less power. Harvesting is done with different
machinery.

Ah, here is a bit of amusement for you.

http://www.news.com.au/couriermail/story/0,23739,23853730-3102,00.html

Converting units is such a pain, but if I did it correct 905ha is 2200
acres or 3.5 square miles planted in 24 hours. How wide is that rig in
the picture? I'd guess 16 meters. How fast were they pulling that?

--
Phil Hays

Posted by phil hays on July 24, 2008, 1:34 am

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BretCahill wrote:

> Has already been proven to be more cost effective than any diesel
> equivalent, not just in operating costs but overall costs as well.

Show me. Get one in the field for long enough to find out battery
replacement costs and such what costs. Build a recharger, and find out
what sort of power the REA will deliver. No offense, but

And don't forget:

The alternative isn't just diesel, it is also biodesel and other biofuels.

> In 6 years the diesel equivalent will be $3000 - $5500/hr.

So how much will the wood for a steam tractor run?

--
Phil Hays

Posted by on July 24, 2008, 2:52 am

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> > Has already been proven to be more cost effective than any diesel
> > equivalent, not just in operating costs but overall costs as well.

> Show me.

Buy two Teslas for $100K each then scrap them for the motors and
batteries.

Already you've saved money compared to the diesel, maybe even in
initial cost alone!

> Get one in the field for long enough to find out battery
> replacement costs and such what costs.

Every cost is _already_ well known and can be easily calculated by any
IEOR.

> Build a recharger,

What next? Reinvent the wheel?

> and find out
> what sort of power the REA will deliver. No offense, but

> And don't forget:

> The alternative isn't just diesel, it is also biodesel and other biofuels.

And you're whining about about battery technology being unproven?

? ? ?

We _know_ everything about the batteries. They already exist. We
only have _claims_ for the algae.

> > In 6 years the diesel equivalent will be $3000 - $5500/hr.

> So how much will the wood for a steam tractor run?

Not nearly negative enough to pay for the time you'll spend scraping
the creosote, slag, ash, tar and other carcinogic crap off the 1/2
mile of fire tubing.

What's wrong with burning bio at a utility power plant set up to burn
bio?

A pizzeria is set up to make pizza.

A farm is set up to cultivate fields with grid power.

And a stationary power plant is set up to make power from bio.

Read the _Republic_ where each person does a specific task.

Bret Cahill

Posted by Mark Thorson on July 24, 2008, 2:17 pm

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BretCahill@peoplepc.com wrote:

>
> Not nearly negative enough to pay for the time you'll spend scraping
> the creosote, slag, ash, tar and other carcinogic crap off the 1/2
> mile of fire tubing.

There's nowhere close to that much tubing.
And all of that stuff would be burnt off
at the operating temperature.

You originally tried to dismiss the steam
tractor with the spectre of boiler explosions,
which are a non-issue for firetube boilers.

When that failed, you retreated to this
equally bogus argument. You don't know the
facts, and try to dismiss what you don't know
with hand-waving.

Steam has been practical for powering tractors
in the past, and with modern materials it
could be even more competitive. Best of all,
it is the ultimate flex-fuel vehicle, because
the fuel doesn't need to burn at a precise
rate under confinement. It doesn't even need
to be a liquid. It could even be coal (our
most abundant fuel), or wood (our most abundant
renewable fuel).

It's far more practical than hauling 10 tons
of batteries around. It's also more efficient
because it only converts chemical energy into
mechanical work. The battery-powered tractor
requires converting chemical energy into
mechanical work (at the power plant), converting
mechanical work into electricity (at the power
plant), transmission line losses, converting
electricity into chemical energy (charging the
tractor's battery), converting chemical energy
into electricity (discharging the battery),
and converting electricity into mechanical work.
You lose energy at every conversion step.
Game over. Not practical.

Posted by Bret Cahill on July 24, 2008, 5:28 pm

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> > Not nearly negative enough to pay for the time you'll spend scraping
> > the creosote, slag, ash, tar and other carcinogic crap off the 1/2
> > mile of fire tubing.

> There's nowhere close to that much tubing.

Then it ain't 400 hp.

> And all of that stuff would be burnt off
> at the operating temperature.

That's a pipe dream.

=2E . .

> It's far more practical than hauling 10 tons
> of batteries around.

That's the point of the trolly wire. The size of the battery can be
reduced by 1 - 2 orders of magnitude because, unlike an EV or plug in,
the tractor charges up every 6 - 10 minutes, after each pass.

A Tesla equivalent battery will work in most applications, very light
for a tractor.

The capital cost would in the long run be even lower.

> It's also more efficient
> because it only converts chemical energy into
> mechanical work. =EF=BF=BD

Not nearly as efficient as a real power plant burning bio.

Bret Cahill

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Hobby Electronics Basics Re: 300 kW EV Tractor vs 400 hp Diesel