Re: Grid-Battery "Hybrid" Tractors



One with lots of small cells. The smaller the cells, the faster the charging time.

The grid: Coal fired plants, nukes, PV, dish Stirling, geo thermal, wind . . . whatever they got that will put out some juice. Polar bears, tropical frogs and hurricanes are not the issue.

Plug in hybrids can go 40 miles between charges. A tractor may require 20X higher hp than a Volt but a tractor only needs to go 1 mile between charges.

If a 400 hp articulated tractor moves 10 mph it's only running 6 minutes between charges and will require 3X 400 hp or ~ 1 MW -- 1/6th the juice drawn by an electric locomotive.
In 4 years diesel will be $15 / gallon and electrification will amount to hundreds of dollars/hour in savings, much more money than necessary to hire someone willing to sit at the end of the field for a few minutes reading a magazine charging up between furrows.

It's only a half mile so a fat high current low voltage wire might be desirable for safety reasons.

Regardless of the size, from the articulated tractor sucking down 22 gallons of diesel/hour [$110/hr and spiraling] to a 15 hp garden tractor, the battery + electric motor system will always have a higher specific power than any IC engine + fuel tank system.
The reason is a tractor just doesn't need to go very far to work a field.

Same as the batteries in plug in hybrids which require an even larger battery / hp.

In as little as 8 years a lot of the big wells will give out rather quickly leaving the world with 2/3rds of current production according to a recent _London Times_ interview with a former BushCo aid. On top of that China seems to have a permanent double digit growth rate while, according to Soros, the U. S. will be in a decades long recession so the size of China's economy will surpass America's in as little as 6 years. This will leave the great majority of Americans to try to get by on a couple percent of the oil we consume today.
So here are 3 plausible scenarios:
1. electrify the fields & tractors, or,
2. return to plowing fields with oxen, or,
3. starve.
If you cannot come up with any ideas, cheap or otherwise, for a plausible 4th scenario then I say we electrify the fields.
Bret Cahill
"Every idea is the product of a single mind."
-- Bishop Richard Cumberland
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And the tractor goes one mile.
Or 1/2 mile.
Recharge time is two orders of magnitude less than the Volt.
Bret Cahill
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On Tue, 22 Jul 2008 14:32:57 -0700 (PDT), Bret Cahill

Your ideas are excellent. Take them to one of the agriculture-related newsgroups, where people will be grateful for your brilliant suggestions. I'm sure all the farmers in the USA will be cutting spiral rows next season.
John
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wrote:

It's more likely that we will move to no-till agriculture.

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wrote:

Lots of things are practical if yoy kill off about 96% of the population first.
John
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You dodged the issue:
Paying $100 billion a year for diesel for agriculture will _starve_ the population.
Bret Cahill
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On Tue, 22 Jul 2008 21:29:54 -0700 (PDT), snipped-for-privacy@peoplepc.com wrote:

Is that $100b number for the US, or for the whole world?
John
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On Tue, 22 Jul 2008 21:29:54 -0700 (PDT), snipped-for-privacy@peoplepc.com wrote:

--
Got some numbers?

JF

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On Tue, 22 Jul 2008 21:29:54 -0700, BretCahill wrote:

Just another tool in the fight against obesity.
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What'll happen is they'll get together more often, i. e., public transportation, and eat even more.
Bret Cahill
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....

Not sure why you change the topic.
My remark was serious : Farmers in the United States already use no-till methods on 37 percent of the nation's cropland. It's likely to increase, since there are many benefits. Only one of these benefits is less fuel needed (since no plowing is done).
Rob
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On Tue, 22 Jul 2008 17:38:25 -0700, Rob Dekker wrote:

Do you actually kno what no till agriculture is?
Hint, it involves a sod seeder instead of a combine & ploughing.
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The Issue has _always been_ liquid fuel costs.
There is no reason to electrify the farms if diesel wasn't spiraling.
. . .

And it "came out" in 6 - 10 minutes.
The tractor is moving 6 - 10 mph.
Alternatively, if the tractor is moving slowly, then it won't require 400 hp, and you'll _still_ have a short charging time.
You keep trying to dodge the fundamental reason this is a better application of batteries than the wildly popular plug in hybrids:
Unlike EVs or plug ins the tractor never goes very far from the charger.
The batteries can therefore be small and cheap and have short charging times.
And we haven't gotten to the favorable torque/rpm curve of electric motors which allows a much smaller hp motor.
Bret Cahill
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On Tue, 22 Jul 2008 16:27:09 -0700 (PDT), snipped-for-privacy@peoplepc.com wrote:

Didn't somebody already invent gears?
John
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You _want_ to go Rube Goldberg?
If your goal is to cost farmers more money then that explains a lot.
Bret Cahill
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On Thu, 24 Jul 2008 12:44:16 -0700 (PDT), snipped-for-privacy@peoplepc.com wrote:

Tell us about your farming experience.
John
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On Thu, 24 Jul 2008 12:44:16 -0700 (PDT), snipped-for-privacy@peoplepc.com wrote:

--
So you don't even understand the function of a transmission?

_That_ explains a lot.
  Click to see the full signature.
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On Fri, 25 Jul 2008 06:41:11 -0500, John Fields

Tee-hee, imagine an electric motor coupled directly to the drive wheels of a tractor.
John
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On Fri, 25 Jul 2008 13:48:21 -0700, John Larkin

--
Not to add fuel to Brat's fire, but... Big-ass PWM controller?

JF

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The problem is getting enough torque at the low RPMs. It might be possible to design a really large wheel motor with, say, 64 poles, that would run at 112 RPM at 60 Hz, but a really large wheel would still not have enough torque to meet the requirements. Gears or some other speed reduction mechanism are definitely needed for a tractor. Hydraulic motors are a possibility, but they are probably not as efficient as a well made gear train.
Tractor transmissions are already well-defined for an engine with about 1800 to 3600 RPM, so an electric motor would be an easy direct fit.
Paul
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