# 300 kW EV Tractor vs 400 hp Diesel

The Tesla is powered by 7,000 Li-Ion laptop batteries for an output of 200 kW.
A similarly powered 300 kW electric tractor (10,500 batteries) would
turn a 400 hp articulated 22 gallon/hour diesel tractor every which way but loose in a tractor pull which apparently is vitally necessary education as well as entertainment for those too ignorant do basic IEOR calculations.
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.
It would also require 17,000 gallons of diesel.
Today the cost is "only" \$80,000 for the diesel.
In 2 years, with the price of hydrocarbon fuel spiraling by 30% a year, that cost will be \$150,000/yr.
In six years the cost of the fuel will be half a million dollars.
And that's just for one field.
Maybe if we have massive truck and bus conversion to natural gas -- include farm tractors in Pickens plan -- the price will "only" be \$350,000/field in 6 years.
The battery tractor would be cheaper even if grid power tripled and even if you went to your overpriced Apple Inc. store and bought the batteries one by one and wired them together one by one yourself.
Now, if you don't believe laptop batteries exist, please go to alt. conspiracy and post there.
Bret Cahill
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I think your numbers are off.
Extrapolating from table 2 at this URL,
http://www.ext.colostate.edu/PUBS/farmmgt/05006.html
I guestimate it'll take roughly 1,075 gallons of diesel to plow a square mile 8 inches deep, and take approximately 64 hours to do it using a 244 hp tractor.
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In that case we can get by with a much smaller battery.
My numbers were based on those provided by some "expert" claiming that was a farming operation that would take an hour to go half a mile and require 400 hp.
Bret Cahill
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BretCahill wrote:

For short periods of time.

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.

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?
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Phil Hays

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BretCahill wrote:

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.

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

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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!

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

What next? Reinvent the wheel?

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

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.
Bret Cahill
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snipped-for-privacy@peoplepc.com wrote:

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.
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Then it ain't 400 hp.

That's a pipe dream.
. . .

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.

Not nearly as efficient as a real power plant burning bio.
Bret Cahill
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Bret, if the tractor goes (what was it?) 1 mph or so, and it needs 10 minutes for one pass (5 min each way), then the field is no wider than 440 feet. Is that a reasonable assumption ?
If so, why not just use a high-voltage extension cable ?
Actually, a 10kV line can be miles long without too many losses (for the 300 kW that you need).
Rob
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Some moron put the 0.5 mph figure. According to some government or industry site posted here, for almost all operations, the tractor is moving 6 - 10 mph.

The cheapest system is a 1/2 mile long wire and a Tesla sized battery.
Bret Cahill

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No. As one poster citing government and industry material pointed out, tractors generally go much faster.

Another moveable wire off of the stationary wire?

Losses aren't an issue.
Bret Cahill
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..

More like two winches with 1 mile wire each (connected in series). One winch unrolls along the side of the field, The other unrolls over the field towards the tractor. Just need a system to make sure the field wire stays high above the tractor (so it does not accidentally get cut).

As long as they stay withing reasonable limits. Which should be OK for (standard) 11kV AC distribution power line and a few miles of cable.
Rob
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On Thu, 24 Jul 2008 20:56:36 -0700 (PDT), Bret Cahill
--
So, you don't know anything about electrical power distribution
either?
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. . .

Because they are long haul, over a hundred miles in many cases. The quarter square tractor trolly line only needs to go half a mile.
Are you just acting dumb or are you really this stupid in real life?
Bret Cahill
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On Sat, 26 Jul 2008 14:39:03 -0700 (PDT), Bret Cahill

Half a mile from where? An electrical outlet conveniently located in the middle of 800 acres of corn field?

Please refresh us on your background in electrical engineering, and in farming.
John
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On Thu, 24 Jul 2008 20:56:36 -0700 (PDT), Bret Cahill

--
Ah, you finally took enough rope... :-)

JF

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On Thu, 24 Jul 2008 20:56:36 -0700 (PDT), Bret Cahill

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Really?

Let's say you need 400HP out of a motor which is 90% efficient and
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Not that your numbers are any good -- electric motors are 95% efficient and don't need to "idle" at the end of the field for 15 minutes while the farmer gets ready for the next pass -- but what is the conclusion when the cost of diesel goes up 30% a year, more than enough to wipe out the 27% loss?
Are you suggesting we should wait another year before designing the system?
Are you just acting dumb or are you really this stupid in real life?
Bret Cahill

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On Sat, 26 Jul 2008 15:42:52 -0700 (PDT), Bret Cahill

--
I've given you the method which will allow you to figure it out for
yourself, so plug your numbers into it and figure it out and stop
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Why doesn't this apply to hybrid road motor vehicles?
You keep dodging that issue and you expect to get better results.
If you are incapable of reasoning and facing the reality that hybrids exist, then all the "calculations" in the world are useless.
You were doing just as good using the word "huge."
Are you just acting stupid or are you really this dumb in real life?
Bret Cahill