Grid-Battery "Hybrid" Tractors

[John Larkin]

On Tue, 22 Jul 2008 14:32:57 -0700 (PDT), Bret Cahill
<BretCahill@aol.com> wrote:

Just one 1/2 mile long wire on one end of a quarter square. ?The
tractor only needs a small battery to make each pass, about a mile.

With two wires, one at each end, the battery can be even smaller.

The GM Volt goes 40 miles between charges. ?The tractor goes one mile.

Or 1/2 mile.

In electric-only mode, the Volt will go 40 miles between charges.

And the tractor goes one mile.

Or 1/2 mile.

Recharge time is two orders of magnitude less than the Volt.


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

 

[Bret Cahill]

Just one 1/2 mile long wire on one end of a quarter square. �The
tractor only needs a small battery to make each pass, about a mile.

With two wires, one at each end, the battery can be even smaller.

The GM Volt goes 40 miles between charges. �The tractor goes one mile.

Or 1/2 mile.

In electric-only mode, the Volt will go 40 miles between charges.

And the tractor goes one mile.

Or 1/2 mile.

Recharge time is two orders of magnitude less than the Volt.


Bret Cahill

 

[terryc]

On Tue, 22 Jul 2008 12:18:15 -0700, Bret Cahill wrote:

What farming operation requires 400 hp to go 0.5 mph?
Ploughing, broad acre sowing, harvesting.

 

[terryc]

On Tue, 22 Jul 2008 08:33:10 -0700, BretCahill wrote:

Much less on a unit power basis than any plug in hybrid. The tractor
never needs to go more than a mile or, using two wires, a half mile
between charges.

So everytime the farmer moves the tractor between fields what does he do?

How do you propose to get around the soil compaction problem? This tractor
that only has to go a mile has to do an enormous amount of travelling too
and from the charging point?

 

[terryc]

On Tue, 22 Jul 2008 10:17:29 -0700, BretCahill wrote:

I'd like to see him connect the charger to that mythical battery

You actually admit you never heard of a rechargeable battery before?

Recharging the battery that you would need for your idea is very diferent
from popping a D cell in a little recharger. Given the current needed to
flow, any loose cables would be a danger to life and limb.

 

[terryc]

On Tue, 22 Jul 2008 08:47:19 -0700, BretCahill wrote:

You don't know what you're talking about.
Steam is mechanically far simpler than ICE.

But far more complicated, more expensive, required more maintenance
and is less efficient than than an electic motor powered by bio mass
burned at a power plant.

umm, hasn't this argument degenerated to whther the steam boiler is large
one at a power station or lots of little ones in paddocks?

 

[Don Bowey]

On 7/22/08 4:53 PM, in article pan.2008.07.22.23.53.09.183481@woa.com.au,
"terryc" <newssixspam-spam@woa.com.au> wrote:

On Tue, 22 Jul 2008 12:18:15 -0700, Bret Cahill wrote:


What farming operation requires 400 hp to go 0.5 mph?
Ploughing, broad acre sowing, harvesting.

Also a process I believe is called sub-soiling where a large machine turns
the soil from about 5 feet below the surface.

 

Not that pausing a few minutes is a problem either but a fast
recharging battery just isn't a serious issue.

All that is necessary is make the cells smaller.

The smaller the cell, the faster the recharge.

This should be common knowledge.

Bret Cahill

Show us a link to a datasheet for such a battery.

Meanwhile, consider a AA size battery with, say, a 2 AH capacity.
Consider charging it in one minute.

See the problem?

No, at least nothing compared to the problem of paying $30 billion a
year -- soon to be $100 billion/yr -- for diesel used in agriculture.

---
Avoiding the issue by changing the subject, are we???

The Issue has _always been_ liquid fuel costs.

There is no reason to electrify the farms if diesel wasn't spiraling.


. . .

If a battery with a capacity of 2 AH (120 ampere-minutes) needs to be
recharged in two minutes, then you've got to fill it back up with the
same amount of electricity, but you've only got 2 minutes to do it in,
so you've got to pump it in faster than it came out. ďż˝

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

 

[John Larkin]

On Tue, 22 Jul 2008 17:38:25 -0700, "Rob Dekker" <rob@verific.com>
wrote:

"John Larkin" <jjlarkin@highNOTlandTHIStechnologyPART.com> wrote in message newsfoc84prrlukm3jsshoebtmeg1aqt2urc9@4ax.com...
On Tue, 22 Jul 2008 14:32:57 -0700 (PDT), Bret Cahill
BretCahill@aol.com> wrote:

Just one 1/2 mile long wire on one end of a quarter square. ?The
tractor only needs a small battery to make each pass, about a mile.

With two wires, one at each end, the battery can be even smaller.

The GM Volt goes 40 miles between charges. ?The tractor goes one mile.

Or 1/2 mile.

In electric-only mode, the Volt will go 40 miles between charges.

And the tractor goes one mile.

Or 1/2 mile.

Recharge time is two orders of magnitude less than the Volt.


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

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

Lots of things are practical if yoy kill off about 96% of the
population first.

John

 

[John Larkin]

On Wed, 23 Jul 2008 09:01:18 +1200, Phil scadden
<p.scadden@_no_spam_gns.cri.nz> wrote:

This discussion has absolutely nothing to do sci.math.num-analysis (or
most of the other groups). Kindly take discussion somewhere else.

It's an unmoderated group. Just ignore the thread.

John

 

[John Larkin]

On Tue, 22 Jul 2008 16:27:09 -0700 (PDT), BretCahill@peoplepc.com
wrote:

And we haven't gotten to the favorable torque/rpm curve of electric
motors which allows a much smaller hp motor.

Didn't somebody already invent gears?

John

 

[John Larkin]

On Tue, 22 Jul 2008 21:29:54 -0700 (PDT), BretCahill@peoplepc.com
wrote:

Just one 1/2 mile long wire on one end of a quarter square. ?The
tractor only needs a small battery to make each pass, about a mile.

With two wires, one at each end, the battery can be even smaller.

The GM Volt goes 40 miles between charges. ?The tractor goes one mile.

Or 1/2 mile.

In electric-only mode, the Volt will go 40 miles between charges.

And the tractor goes one mile.

Or 1/2 mile.

Recharge time is two orders of magnitude less than the Volt.

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

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

Lots of things are practical if yoy kill off about 96% of the
population first.

You dodged the issue:

Paying $100 billion a year for diesel for agriculture will _starve_
the population.

Is that $100b number for the US, or for the whole world?

John

 

[John Larkin]

On Tue, 22 Jul 2008 21:45:32 -0700 (PDT), BretCahill@peoplepc.com
wrote:

Not that pausing a few minutes is a problem either but a fast
recharging battery just isn't a serious issue.

All that is necessary is make the cells smaller.

The smaller the cell, the faster the recharge.

This should be common knowledge.

Bret Cahill

Show us a link to a datasheet for such a battery.

Meanwhile, consider a AA size battery with, say, a 2 AH capacity.
Consider charging it in one minute.

See the problem?

No, at least nothing compared to the problem of paying $30 billion a
year -- soon to be $100 billion/yr -- for diesel used in agriculture.

---
Avoiding the issue by changing the subject, are we???

_You_ not "we."

The original issue was _always_ the $100 billion wasted on diesel.

Who wastes $100b a year on diesel?

John

 

[phil hays]

BretCahill wrote:

The problem in the real world is things go wrong.

So? Horses bolt and/or kick. Everything has risks and costs, can't avoid
either, so need to pick the best compromise.

A steam tractor would have a much higher initial cost and require much
more maintence and training necessary than even an ICE. Unless you had
a steam - electric hybrid the load couldn't be changed rapidly. Either
you waste steam or time. Algae diesel is more promising.

Hmm, I almost mentioned various biodiesel options as well. Both steam and
biodiesel seems better to me than an battery powered tractor. I'd guess
both would be cheaper initial cost.

Suppose we have a 240 kW tractor. This would be similar to common diesel
tractors. If we run it for a row and then recharge after a mile at the
same rate as it was discharged, we need to charge the batteries at
something over 240 kW. To put this in perspective, many houses in the USA
are limited at 24 kW. Such a house is supplied with 240 V at a maximum
current of 100 A. 240 V is hazardous to handle, and 100 A requires large
cables well connected. Both would be problems in a field environment. And
we need more than ten times as much power.

Ever drive a tractor, say pulling a disk? Load doesn't change hardly at
all, all day. Same speed, about the same pull, no problem at all for a
steam tractor. Yes, more labor running one than an ICE, but after the oil
is gone...

Biodiesel requires specific fuels, rather than anything from straw to
wood, but would have other advantages, such as higher power to weight
ratios.

Biofueled tractors win over horses and oxen both on fuel consumption and
less labor needed to farm. Probably safer as well. Battery powered
tractors are not competitive.


--
Phil Hays

 

Just one 1/2 mile long wire on one end of a quarter square. ?The
tractor only needs a small battery to make each pass, about a mile.

With two wires, one at each end, the battery can be even smaller.

The GM Volt goes 40 miles between charges. ?The tractor goes one mile.

Or 1/2 mile.

In electric-only mode, the Volt will go 40 miles between charges.

And the tractor goes one mile.

Or 1/2 mile.

Recharge time is two orders of magnitude less than the Volt.

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

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

Lots of things are practical if yoy kill off about 96% of the
population first.

You dodged the issue:

Paying $100 billion a year for diesel for agriculture will _starve_
the population.


Bret Cahill

 

This discussion has absolutely nothing to do sci.math.num-analysis (or
most of the other groups). Kindly take discussion somewhere else.

It's an unmoderated group. Just ignore the thread.

We need applied math folk for the final spreadsheet work. No reason
to piss 'em off.


Bret Cahill

 

Not that pausing a few minutes is a problem either but a fast
recharging battery just isn't a serious issue.

All that is necessary is make the cells smaller.

The smaller the cell, the faster the recharge.

This should be common knowledge.

Bret Cahill

Show us a link to a datasheet for such a battery.

Meanwhile, consider a AA size battery with, say, a 2 AH capacity.
Consider charging it in one minute.

See the problem?

No, at least nothing compared to the problem of paying $30 billion a
year -- soon to be $100 billion/yr -- for diesel used in agriculture.

---
Avoiding the issue by changing the subject, are we???

_You_ not "we."

The original issue was _always_ the $100 billion wasted on diesel.


Bret Cahill

 

What farming operation requires 400 hp to go 0.5 mph?
Ploughing, broad acre sowing, harvesting.

Also a process I believe is called sub-soiling where a large machine turns
the soil from about 5 feet below the surface.

Then call in a service company with a bigger battery.


Bret Cahill

 

Not that pausing a few minutes is a problem either but a fast
recharging battery just isn't a serious issue.

All that is necessary is make the cells smaller.

The smaller the cell, the faster the recharge.

---
And the more expensive the finished battery cost per watt-hour.

The tractor only goes a mile between charges so a tractor battery
doesn't need a lot of watt-hours / work done.

---
Really?

Your 400 horsepower tractor, working for an hour, would need a battery
which can supply about 300KWH, (300 000 watt-hours) and if it's doing
it with an output voltage of 300V that means it needs to be rated for
an output of 1000AH at C/1.

That's a lot of watt-hours and a lot of work done.

True.

Not true.

The tractor only needs to make one "lap" between charges -- a few
minutes.

Any argument for plug ins is an *a fortiori* argument for grid-battery
powered tractors.


Bret Cahill

 

how much do they cost,
Whatever happened to rugged induhvidualism? ?Visitwww.homedepot.com
and look it up.
? ?Whatever happened to clear thought,

IWe're still waiting for some clear thinging on the fundamental
differences between plug in hybrids and grid-battery tractors.

Bret, I admire your out-of-the-box idea of battery-driven tractors, I don't think that full-electric tractors are going to show up
any time soon.

I have no problems with a _small_ ICE on the tractor.

Couple of differences with plug-in hybrid passenger vehicles come to mind :
- The use diesel, which has a higher value of combustion than gasoline cars, and higher in efficiency than gasoline cars.

And?

- They are (when working) operating at near-optimal efficiency (constant high power; near the most efficient RPM possible).
- The don't gain much from regenerative breaking.

These seem to be more a fortiori arguments for electrifying the farm.

- Tractors are essentially a big engine on wheels. Their entire purpose is to provide high-power for an entire work-day out in the
field.

Sounds like the perfect application for a high low end torque electric
motor.

The diesel tank is configered accordingly.

You mean the diesel tank that dumps $300/hour down the drain?

THAT diesel tank?

Battery technology is not competitive with such modes of operation. In my back-of-the-envelope calculations, we need a 6-10X
improvement of battery energy density (w.r.t. Li-ion) before the range can be matched with equal power and equal weight.

But the tractor only needs a battery that'll last a few minutes.

Battery tech IS competitive for passenger vehicles,

Which must run _much_ longer times between charging than the tractor.

although even there we need to compromise on the driving range (hence PHEVs). So
from all the vehicles around, tractors have a lower chance of going full-electric for a while.

They have a _better_ chance because they never go very far.

Different story for electric-drive tractors. Electric-drive (such as used in diesel-electric locomotives) does save fuel, increases
torch, and simplifies operation.
Caterpillar has at least one of these fuel savers :http://www.heavyequipmentforums.com/Forum/showthread.php?t=5853

OK, then we're ready to install a wire and electrify the farm!

Kudos for Cat!

Smaller tractors (lawn-mowers and other etc) could actually go electric rather easily.

There are no negative economies of scale here.

I already provided one difference: �The tractor battery only needs a
charge that will last a few minutes, an order of magnitude less time
than the hybrid.

True, if it needs to re-charge during the work day.
10 recharges during a work-day would compensate for the 10X difference in battery tech.
So your idea might work IF the farmer finds it acceptable to re-charge 10X per work day.

What other choice does he have?

Running diesel from Mexico 20X times/day?

And even _that_ ridiculous solution cannot last long because the
governors of the border estados have started going to Mexico City to
whine that they cannot handle the demand caused by gringo farmers.

It's a whole lot easier and more cost effective to just go electric.

This diesel nonsense is for the birds.


Bret Cahill