Grid-Battery "Hybrid" Tractors

[John Fields]

On Fri, 25 Jul 2008 18:57:25 -0400, "Paul E. Schoen"
<pstech@smart.net> wrote:

"John Fields" <jfields@austininstruments.com> wrote in message
news:0lgk84dr7t0bhgh40rsia8e697hr4rptnc@4ax.com...
On Fri, 25 Jul 2008 13:48:21 -0700, John Larkin
jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:

On Fri, 25 Jul 2008 06:41:11 -0500, John Fields
jfields@austininstruments.com> wrote:

On Thu, 24 Jul 2008 12:44:16 -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?

You _want_ to go Rube Goldberg?

If your goal is to cost farmers more money then that explains a lot.

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

_That_ explains a lot.

JF

Tee-hee, imagine an electric motor coupled directly to the drive
wheels of a tractor.

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

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.

---
Good point.
---

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.

---
That's interesting in that the motor could run at a more or less
constant, efficient speed, powered by AC mains, and transfer power to
the wheels or to the PTO via electronically controlled transmissions.

What about the size of the motor and cooling requirements VS those for
an ICE?

JF

 

[terryc]

On Fri, 25 Jul 2008 18:57:25 -0400, Paul E. Schoen wrote:

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.

I think we are really just arguing about the mythic lightweight super
capacity battery pack and or the relative cost of the massive central
pivot power supply, not to mentin the $AUSX00,000 is going to charge you
to bring in an 11Kv feed.

<imagine the speed of the outside support of a central pivot supply as the
tractor ploughs the inner rings {>

 

[terryc]

On Fri, 25 Jul 2008 10:51:18 -0500, John Fields wrote:

That's typical for _any_ flooded lead-acid battery, while much higher
efficiencies can be enjoyed by using SLAs. Including theirs, I
suppose.

Conflicts with other stuff I've read claiming 110%.

 

[ehsjr]

Rob Dekker wrote:

"Mark Thorson" <nospam@sonic.net> wrote in message news:4889025D.EB3033EB@sonic.net...

Bret Cahill wrote:

The small cell phone or lap top batteries wired in parallel would
charge up in a couple of minutes.

10 recharges during a work-day

I was planning for 6 - 10 an hour.

Every time the tractor makes it across the field or back it recharges.

Laptop batteries are typically good for about 1000 charges
before becoming seriously degraded. �Your hypothetical
tractor would need a fresh set of batteries about every
2 weeks. �You haven't taken this major cost into account.

How would this cost be any different than the plug in hybrid or EV
like the Tesla?

Because a car is only charged once or twice a day.
If we assume an 8-hour shift, your tractor
is being recharged 48-80 times a day. If this
big, expensive tractor is used for multiple
shifts, it could be much higher than that.
You'll be producing mountains of dead, expensive
batteries. There isn't enough hazmat landfill
to handle them all.


Please RECYCLE batteries.
The metals in there are valuable (especially for lithium-based cells).

Although for tractors, you probably would not use Li-ions that are designed for small applications, although even these would
already be economical (as Tesla shows).
But for tractors, the low-cost, high energy density molten salt batteries (Zebra's, sodium/sulfur etc) are excellent :

http://en.wikipedia.org/wiki/Molten_salt_battery

Cheap, powerfull, thousands of cycles, and easy to recycle.
With their high operating temperatures, these are rather 'clumsy' for small applications.
But for tractors, busses and anything big, they should be great.

Rob

The site give the specs for a Zebra battery at 90 Wh/kg.
The 300 kWh tractor used as an example in the thread
would require well over 7000 pounds of those batteries,
which would occupy over 78 cubic feet. That volume
computation is based on the example given of a 195 kg
Zebra at .13 cubic meter. See
http://www.rolls-royce.com/marine/downloads/submarine/zebra_fact.pdf

The battery operating temperature is 250 C and must be
kept under charge when not in use to keep the temperature
there. If you allow it to cool, it can take up to 2 days
to get it up to temperature again before you can use it.

The farmer who has a tractor powered by this type of battery
is going to have one helluva job removing 7333 pounds of
batteries and hauling that to the recycler, and another
helluva job of installing the 7000 plus pounds of replacement
batteries.

I did not find recharge time, but it will certainly cut into
the farmer's productivity, as compared to diesel.

Based on what is posted on the Wiki site and the thread
here, the idea that this technology, as it is today, can
be a practical alternative to diesel in tractors is totally
ludicrous. And that is without considering the purchase
price of the batteries and charging equipment, or the
cost of installing the charging equipment.

Ed

 

[John Fields]

On Fri, 25 Jul 2008 20:37:17 -0400, "Paul E. Schoen"
<pstech@smart.net> wrote:

"John Fields" <jfields@austininstruments.com> wrote in message
news:rgok845b855b1i0q7gtn4p876ohbdrnaf4@4ax.com...
On Fri, 25 Jul 2008 18:57:25 -0400, "Paul E. Schoen"
pstech@smart.net> wrote:


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.

---
Good point.
---

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.

---
That's interesting in that the motor could run at a more or less
constant, efficient speed, powered by AC mains, and transfer power to
the wheels or to the PTO via electronically controlled transmissions.

What about the size of the motor and cooling requirements VS those for
an ICE?

An AC induction motor exhibits a fairly flat torque curve from something
like 10% of design RPMs at 50/60 Hz, and then is usually shown as
decreasing, because, although motors can be driven by PWM to several times
their rated speed, it is not usually recommended (or feasible) to increase
the voltage accordingly (as a VF drive does). But there is nothing "magic"
about 60 Hz as a limit for the magnetics, and it is possible to design
motors that run up to at least 400 Hz. They are typically very high RPM,
but with enough poles, it is possible to boost the HP of a motor by several
times, using lower voltage windings and running at least up to 150 Hz. You
can get 2 or three times the HP from the same size motor. This is very
important for highway vehicles, where the weight and size of the motor
contribute a lot to fuel economy and performance, but probably not as much
for a tractor, where additional weight might be a good thing.

Since large induction motors are typically 92 to 95% efficient, a 75 kW 100
HP motor will produce something like 5000 watts of heat, which is removed
by means of self-contained fans. A motor specially designed to be
overdriven might be even more efficient, although there is a limit where
magnetic losses take over. The good thing about electric motors is that
they consume no power when they are idle, and their losses are at worst a
percentage of the actual output power, and may even be less when lightly
loaded. Losses are proportional to I^2, while torque is proportional to I.
They can also be "pushed" to 2 or 3 times their nameplate ratings for short
periods of time, so you can often get by with a smaller motor if your power
needs are intermittent.

So the transmission requirements are mostly to provide the needed torque,
and then the motor speed can be adjusted as needed. Large tractors probably
have trannies with 10 or 15 speeds or more, while an electric motor might
require only 3 or 4. This would be another saving. VF drives are so
efficient and inexpensive now, that any other motor controller is just
about unthinkable. And you can run a VF drive on 720 VDC directly, so it is
ideally suited to a battery pack for use when transferring from one power
source to another. This would require much less power than the tractor is
actually rated for, so the battery pack could be quite small.

---
Very nice.

Thanks!

JF

 

[John Larkin]

On Fri, 25 Jul 2008 16:17:47 -0500, John Fields
<jfields@austininstruments.com> wrote:

On Fri, 25 Jul 2008 13:48:21 -0700, John Larkin
jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:

On Fri, 25 Jul 2008 06:41:11 -0500, John Fields
jfields@austininstruments.com> wrote:

On Thu, 24 Jul 2008 12:44:16 -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?

You _want_ to go Rube Goldberg?

If your goal is to cost farmers more money then that explains a lot.

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

_That_ explains a lot.

JF

Tee-hee, imagine an electric motor coupled directly to the drive
wheels of a tractor.

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

JF

Unless the thing was 8 feet in diameter (which would have its own
problems) you'd need kiloamps of coil current and megagauss field
strengths to get the kind of torque a tractor wheel would need.

This guy is as ignorant of electrical and mechanical engineering as he
is of farming.

John

 

[John Larkin]

On Sat, 26 Jul 2008 00:11:10 -0700, "Rob Dekker" <rob@verific.com>
wrote:

"Paul E. Schoen" <pstech@smart.net> wrote in message
news:488a71da$0$19697$ecde5a14@news.coretel.net...
....
That's interesting in that the motor could run at a more or less
constant, efficient speed, powered by AC mains, and transfer power to
the wheels or to the PTO via electronically controlled transmissions.

What about the size of the motor and cooling requirements VS those for
an ICE?

An AC induction motor exhibits a fairly flat torque curve from something
like 10% of design RPMs at 50/60 Hz, and then is usually shown as
decreasing, because, although motors can be driven by PWM to several times
their rated speed, it is not usually recommended (or feasible) to increase
the voltage accordingly (as a VF drive does). But there is nothing "magic"
about 60 Hz as a limit for the magnetics, and it is possible to design
motors that run up to at least 400 Hz. They are typically very high RPM,
but with enough poles, it is possible to boost the HP of a motor by
several
times, using lower voltage windings and running at least up to 150 Hz. You
can get 2 or three times the HP from the same size motor. This is very
important for highway vehicles, where the weight and size of the motor
contribute a lot to fuel economy and performance, but probably not as much
for a tractor, where additional weight might be a good thing.

Since large induction motors are typically 92 to 95% efficient, a 75 kW
100
HP motor will produce something like 5000 watts of heat, which is removed
by means of self-contained fans. A motor specially designed to be
overdriven might be even more efficient, although there is a limit where
magnetic losses take over. The good thing about electric motors is that
they consume no power when they are idle, and their losses are at worst a
percentage of the actual output power, and may even be less when lightly
loaded. Losses are proportional to I^2, while torque is proportional to I.
They can also be "pushed" to 2 or 3 times their nameplate ratings for
short
periods of time, so you can often get by with a smaller motor if your
power
needs are intermittent.

So the transmission requirements are mostly to provide the needed torque,
and then the motor speed can be adjusted as needed. Large tractors
probably
have trannies with 10 or 15 speeds or more, while an electric motor might
require only 3 or 4. This would be another saving. VF drives are so
efficient and inexpensive now, that any other motor controller is just
about unthinkable. And you can run a VF drive on 720 VDC directly, so it
is
ideally suited to a battery pack for use when transferring from one power
source to another. This would require much less power than the tractor is
actually rated for, so the battery pack could be quite small.

Paul


Paul,

On behalf of sci.energy readers, THANKS for a great overview of electric
motor basics.
Very seldom do we see postings of this quality, and I at least very much
appreciate that.

It always impresses me that a lot of people participate in specialty
newsgroups, and have opinions about technology and public policy,
without making any effort to read a few books and understand the
basics of what's actually going on, or the quantitative limits of
what's possible.

My wife wanted me to put a windmill on our roof to make our own
electricity.

John

 

[DB]

ehsjr wrote:

The site give the specs for a Zebra battery at 90 Wh/kg.
The 300 kWh tractor used as an example in the thread
would require well over 7000 pounds of those batteries...

See what happens following Bret's threads......?

 

The small cell phone or lap top batteries wired in parallel would
charge up in a couple of minutes.

10 recharges during a work-day

READ THIS:

I was planning for 6 - 10 an hour.

Every time the tractor makes it across the field or back it recharges.

Laptop batteries are typically good for about 1000 charges
before becoming seriously degraded. �Your hypothetical
tractor would need a fresh set of batteries about every
2 weeks. �You haven't taken this major cost into account.

How would this cost be any different than the plug in hybrid or EV
like the Tesla?

Because a car is only charged once or twice a day.
If we assume an 8-hour shift, your tractor
is being recharged 48-80 times a day.  If this
big, expensive tractor is used for multiple
shifts, it could be much higher than that.
You'll be producing mountains of dead, expensive
batteries.  There isn't enough hazmat landfill
to handle them all.

Please RECYCLE batteries.
The metals in there are valuable (especially for lithium-based cells).

Although for tractors, you probably would not use Li-ions that are designed for small applications, although even these would
already be economical (as Tesla shows).
But for tractors, the low-cost, high energy density molten salt batteries (Zebra's, sodium/sulfur etc) are excellent :

http://en.wikipedia.org/wiki/Molten_salt_battery

Cheap, powerfull, thousands of cycles, and easy to recycle.
With their high operating temperatures, these are rather 'clumsy' for small applications.
But for tractors, busses and anything big, they should be great.

Rob

The site give the specs for a Zebra battery at 90 Wh/kg.
The 300 kWh tractor used as an example in the thread

_What_ example?

_My_ example was for the tractor crossing the field in the typical 6 -
10 minutes. (See above.) The 6 - 10 mph typical tractor speed figure
has been confirmed by other posters citing government and industry web
sites.

A 400 hp tractor running wide open moving at 0.5 mph would require
several months to work one square mile and, in 6 years, at the present
rate of spiraling fuel costs, run up a debt of a half a million
dollars just for the diesel.

The 0.5 mph strawman was generated by a useful idiot who unwittingly
helped me build the case for grid-battery.

would require well over 7000 pounds of those batteries,

Almost all field operations allow the tractor to recharge every 6 - 10
minutes requiring only 10 - 30 kW hrs/charge.

30 kW-hr/(0.09 kW-hr/kg) = 733 lbs. The overall drive train will be
lighter than the diesel + fuel tank.

I've mentioned this several times and everyone dodges this issue:

Grid battery farm electrification is possible with low density energy
storge devices, an advantage not shared by road hybrids or EVs.

Any argument for EVs or hybrid electric is, a fortiori, an argument
for grid-battery tractors.

And, _no_ pausing at the end of the field to recharge is _not_ a big
issue.

Right now farmers are paying truck drivers $100/trip to run 8 peso/
litre diesel from Mexico at a savings of only 40% over U. S. prices.
This ties up truck and driver time.

Instead of paying a truck driver to sit in line at the border why not
pay a tractor driver to sit at the end of the field?

At least you don't getting pestered by customs agents and junk food
peddlers sitting out at the edge of a field.

The hay guys seem to move fast -- they get across the field in 2
minutes -- but the rest spend 15 minutes each lap screwing around at
the end of the field lining up their lasers or whatever anyway.


Bret Cahill

which would occupy over 78 cubic feet.  That volume
computation is based on the example given of a 195 kg
Zebra at .13 cubic meter. Seehttp://www.rolls-royce.com/marine/downloads/submarine/zebra_fact.pdf

The battery operating temperature is 250 C and must be
kept under charge when not in use to keep the temperature
there. If you allow it to cool, it can take up to 2 days
to get it up to temperature again before you can use it.

The farmer who has a tractor powered by this type of battery
is going to have one helluva job removing 7333 pounds of
batteries and hauling that to the recycler, and another
helluva job of installing the 7000 plus pounds of replacement
batteries.

I did not find recharge time, but it will certainly cut into
the farmer's productivity, as compared to diesel.

Based on what is posted on the Wiki site and the thread
here, the idea that this technology, as it is today, can
be a practical alternative to diesel in tractors is totally
ludicrous.  And that is without considering the purchase
price of the batteries and charging equipment, or the
cost of installing the charging equipment.

Ed- Hide quoted text -

- Show quoted text -

 

[Dean Hoffman]

BretCahill@peoplepc.com wrote:

And, _no_ pausing at the end of the field to recharge is _not_ a big
issue.

You have to be kidding. Do you think farmers work almost every
waking moment during planting season because they like the hours?
Patience is in short supply during the spring. Any delay due to
breakdowns and such drives them nuts. The goal is to keep the planters
moving until the job is done.
Planting season starts around April 10 or so in my area of Nebraska.
Things generally get wrapped up by the second or third week in May.

Dean



----== Posted via Pronews.Com - Unlimited-Unrestricted-Secure Usenet News==----
http://www.pronews.com The #1 Newsgroup Service in the World! >100,000 Newsgroups
---= - Total Privacy via Encryption =---

 

And, _no_ pausing at the end of the field to recharge is _not_ a big
issue.

� � � � �You have to be kidding. �Do you think farmers work almost every
waking moment during planting season because they like the hours?
Patience is in short supply during the spring. �Any delay due to
breakdowns and such drives them nuts. ďż˝

Electric motors are more reliable than diesel.

The goal is to keep the planters
moving until the job is done.

The field needs to be automated so that the machinery runs 24/7 with
lasers and GPS. Just put in the crop's CD and the coordinates of the
field.

� � �Planting season starts around April 10 or so in my area of Nebraska.
Things generally get wrapped up by the second or third week in May.

For places with only one or 2 seasons, time is less critical.

When the price of diesel gets high enough it'll be cheaper to run 2
electric tractors and pay two drivers than one diesel.


Bret Cahill

 

And, _no_ pausing at the end of the field to recharge is _not_ a big
issue.

� � � � �You have to be kidding. �Do you think farmers work almost every
waking moment during planting season because they like the hours?
Patience is in short supply during the spring. �Any delay due to
breakdowns and such drives them nuts. ďż˝ The goal is to keep the planters
moving until the job is done.
� � �Planting season starts around April 10 or so in my area of Nebraska.
Things generally get wrapped up by the second or third week in May.

Instead of one 700 lb battery that stays in the tractor, two 350 lb
batteries would be cantilevered off both sides of the tractor with a
wire on both ends of the field. The batteries have a verticle rod
mounted on top to contact the wire.

When the tractor reaches the right hand U turn end of the field the
left outrigger scoops up a recharged battery. After the U turn the
discharged battery is dropped off for charging and can be picked up on
the next lap.

The right side battery is swapped out at the other end of the field
when the left hand U turn is made.

The batteries only last a few weeks and are changed - recycled like
motor oil.

Battery cost is about twice grid cost -- the combination is just now
about equal to the cost of diesel -- so in the long run it might be
cheaper to trolly wire the entire field or go with the super pivot.

There are all kinds of farm situations and there will be all kinds of
solutions.

The original single battery single wire idea where the driver waits at
the end of the field for a recharge was the absolute cheapest easiest
electric tractor to prototype and demonstrate. It was just a way to
get a foot into the extension center door.


Bret Cahill

 

I DID find a manufacturers folder that reports 119 kWh/kg (better than NiMH) :

Energy density just isn't a factor when you can recharge or swap out
batteries several times/hr.

.. . .

Electric drive (like the Caterpillar tractor mentioned earlier) make much more sense currently for efficiency and torque
improvements on big-ass farm equipment.

We really need a tractor pull to show a 350 lb battery just isn't a
big deal.

Barring some breakthroughs in algae, diesel will soon be prohibitively
expensive, with _any_ kind of drive. Why risk the food supply when
there is such an effort to go EV or plug in anyway?

The EV and plug in industry will require much more metal and other
materials for their batteries than agriculture will ever use.

And if battery costs don't drop very much, then there's always
straight grid, either a lot of trolly wires or something based on a
pivot irrigation system.


Bret Cahill

 

[ehsjr]

BretCahill@peoplepc.com wrote:

I DID find a manufacturers folder that reports 119 kWh/kg (better than NiMH) :


Energy density just isn't a factor when you can recharge or swap out
batteries several times/hr.

. . .


Electric drive (like the Caterpillar tractor mentioned earlier) make much more sense currently for efficiency and torque
improvements on big-ass farm equipment.


We really need a tractor pull to show a 350 lb battery just isn't a
big deal.

It is not 350 pounds. Using the numbers posted in the thread
(300kWh equivalent tractor, 90Wh/kg battery) it is over *7333*
pounds of batteries. Energy density most certainly is a
huge factor, if those numbers you & Rob have been posting
are accurate.

A 350 pound Zebra battery would yield 14318 Wh. That is
the equivalent of 19 horsepower - way too small for a
tractor on a farm.

Ed

Barring some breakthroughs in algae, diesel will soon be prohibitively
expensive, with _any_ kind of drive. Why risk the food supply when
there is such an effort to go EV or plug in anyway?

The EV and plug in industry will require much more metal and other
materials for their batteries than agriculture will ever use.

And if battery costs don't drop very much, then there's always
straight grid, either a lot of trolly wires or something based on a
pivot irrigation system.


Bret Cahill

 

[Bret Cahill]

I DID find a manufacturers folder that reports 119 kWh/kg (better than NiMH) :

Energy density just isn't a factor when you can recharge or swap out
batteries several times/hr.

. . .

Electric drive (like the Caterpillar tractor mentioned earlier) make much more sense currently for efficiency and torque
improvements on big-ass farm equipment.

We really need a tractor pull to show a 350 lb battery just isn't a
big deal.

It is not 350 pounds.

It's more like 300 lbs max.

Using the numbers posted in the thread
(300kWh equivalent tractor,

What part of "frequent recharge" do you NOT unnerstand?

A 400 hp tractor only needs a couple of gallons to get across a field.

90Wh/kg battery)

Not that it matters but now he's saying 120 w- hr / kg.

it is over *7333*
pounds of batteries. ďż˝

For _what _ operation?

Energy density most certainly is a
huge factor, if those numbers you & Rob have been posting
are accurate.

What part of "frequent recharge" do you NOT unnerstand?

A 350 pound Zebra battery would yield 14318 Wh. �That is
the equivalent of 19 horsepower

Now everyone knows yer an idiot. Energy ain't power.


Bret Cahill

 

On Jul 20, 10:08 am, Bret Cahill <BretCah...@aol.com> wrote:

Supposedly if the tank is connected to the vehicle's engine, it's
technically legal to bring 8 pesos/litre [$3/gallon] fuel across the
border from Mexico. If the tank isn't connected, customs wil seize
the diesel and maybe even the vehicle. Even if it is connected,
customs may give you a hard time. Supposedly a driver can earn $100 a
trip running diesel in border areas but each border crossing takes an
hour or so . . .

Why is fuel so much cheaper in Mexico?

It's a whole lot more cost effective to just electrify the #@!%&*!
tractors and fields.

Yay, mile-long extension cords! Careful not to run over the...
zAAAP! ...never mind...

 

[Bret Cahill]

SINCE ENERGY DENSITY ISN'T SUCH A BIG DEAL, WHAT ABOUT CAPS?

Sorry, no pun intended. My keyboard made an honest mistake.

Anyway, this would need to be spread sheeted to optimize and to
determine competitiveness but several wires over the field could
recharge multi farad capacitors in seconds.

Sure the caps would weigh more than batteries but they'ld last
forever . . .


Bret Cahill

 

[John Fields]

On Thu, 7 Aug 2008 21:32:14 -0700 (PDT), Bret Cahill
<BretCahill@aol.com> wrote:

SINCE ENERGY DENSITY ISN'T SUCH A BIG DEAL, WHAT ABOUT CAPS?

Sorry, no pun intended. My keyboard made an honest mistake.

Anyway, this would need to be spread sheeted to optimize and to
determine competitiveness but several wires over the field could
recharge multi farad capacitors in seconds.

---
"Spread sheeted?"

LOL, you wouldn't even know what to enter into the various cells and
what relationships to assign between them, and yet you pretend to know
how to work out a solution that way?

Plain and simple, you're a fake.

Worse than that, you're a fake who knows he's a fake and yet tries to
bend others to join him in his downward death spiral.

Kind of like Jim Jones.

But maybe not...

If you're not, then I challenge you to post a .xls file which will
prove your point.
---

Sure the caps would weigh more than batteries but they'ld last
forever . . .

---
Oh, yeah, sure they would.

More of your never ending bullshit.

Nothing lasts forever, and high discharge rate / high charge rate
capacitors which can supply 400 horsepower for times significant
enough to allow a field to be plowed next to a diesel tractor with the
same efficacy are high on the list of things that won't be found
working when your kids sell your farm after you die.

JF

 

[ehsjr]

Rob Dekker wrote:

"Bret Cahill" <BretCahill@aol.com> wrote in message news:95293db8-ddaf-40e9-b931-5f64b0b868c7@r15g2000prd.googlegroups.com...

I DID find a manufacturers folder that reports 119 kWh/kg (better than NiMH) :

Energy density just isn't a factor when you can recharge or swap out
batteries several times/hr.

. . .

Electric drive (like the Caterpillar tractor mentioned earlier) make much more sense currently for efficiency and torque
improvements on big-ass farm equipment.

We really need a tractor pull to show a 350 lb battery just isn't a
big deal.

It is not 350 pounds.


It's more like 300 lbs max.


Using the numbers posted in the thread
(300kWh equivalent tractor,


What part of "frequent recharge" do you NOT unnerstand?

What part of "equivalent tractor" do you NOT understand?
While the battery powered tractor is re-charging, the
diesel is still plowing. Equivalency is lost.

Ed

<snip>

 

I DID find a manufacturers folder that reports 119 kWh/kg (better than NiMH) :

Energy density just isn't a factor when you can recharge or swap out
batteries several times/hr.

. . .

Electric drive (like the Caterpillar tractor mentioned earlier) make much more sense currently for efficiency and torque
improvements on big-ass farm equipment.

We really need a tractor pull to show a 350 lb battery just isn't a
big deal.

It is not 350 pounds.

It's more like 300 lbs max.

Using the numbers posted in the thread
(300kWh equivalent tractor,

What part of "frequent recharge" do you NOT unnerstand?

What part of "equivalent tractor" do you NOT understand?

The part where it makes sense to pay $12/gallon for diesel.

Next question?


Bret Cahill