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Sci.Electronics.Basics -> Even Low Efficiency Energy Storage Devices Become Competitive With Spiraling Fuel Costs
There are 96 messages in this thread.
You are currently looking at messages 1 to 20.
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Author: Bret CahillDate: 13:17 10-08-08
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If energy from the grid costs 13 cents/kW-hr and a 1000 cycle battery
costs 27 cents/kW-hr, and diesel is 40 cents/kW-hr, then a 33%
efficient energy storage device that is capable of thousands of cycles
over its lifetime suddenly starts to look interesting.
Maybe it's possible to trade a little efficiency for higher energy
density or lower initial costs.
For example, the flywheel below is 86% efficient but has an energy
density of only 5.5 W-hr/kg.
It would be cost effective to find something that was only 50% or 40%
efficient but with 10X the energy density.
Bret Cahill
http://www.magma.ca/%7efesi/50kW-1000Wh%20Flywheel%20System.pdf
System Description
Continuous rated power 50 kW
Peak power 120 kW
Charge or discharge time 60 seconds at 50 kW
Mass 135 kg
Volume 110 litres
Diameter 24 in (610 mm)
Height 18 in (460 mm)
Specific power 370 W/kg (continuous)
890 W/kg (peak)
Specific energy 5.5 Wh/kg
Typical DC interface 600 - 750V
Self-discharge rate 0.5 - 1.0 kW
Typical Efficiencies at Rated Power
Motor/generator 98%
Inverter 95%
Net one-way 93%
Net round-trip 86%
Flywheel Rotor
General description Composite flywheel rim with
aluminum hub
Operating speed range 15,500 rpm - 31,000 rpm
Polar inertia 0.720 kg=B7m2
Energy storage 1,000 Wh @ 31,000 rpm
250 Wh @ 15,500 rpm
Net energy storage 750 Wh
Motor/Generator
General description Permanent magnet, 3-phase,
synchronous, liquid cooled
Frequency range 515 Hz - 1,030 Hz
Line-line voltage 230 Vrms at 515 Hz
450 Vrms at 1,030 Hz
Total inductance 100 =B5H
Line-
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Author: Rod SpeedDate: 14:59 10-08-08
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Bret Cahill <BretCahill@aol.com> wrote:
> If energy from the grid costs 13 cents/kW-hr and a 1000 cycle
> battery costs 27 cents/kW-hr, and diesel is 40 cents/kW-hr,
Just more number plucked out of your arse. We can tell from the smell.
> then a 33% efficient energy storage device that is capable of thousands
> of cycles over its lifetime suddenly starts to look interesting.
But doesnt with real numbers.
> Maybe it's possible to trade a little efficiency
> for higher energy density or lower initial costs.
Fraid not.
> For example, the flywheel below is 86% efficient
> but has an energy density of only 5.5 W-hr/kg.
Pity about the other downsides of that.
> It would be cost effective to find something that was only
> 50% or 40% efficient but with 10X the energy density.
No such animal.
> http://www.magma.ca/%7efesi/50kW-1000Wh%20Flywheel%20System.pdf
> System Description
> Continuous rated power 50 kW
Useless as a tractor for any real work.
> Peak power 120 kW
> Charge or discharge time 60 seconds at 50 kW
> Mass 135 kg
> Volume 110 litres
> Diameter 24 in (610 mm)
> Height 18 in (460 mm)
> Specific power 370 W/kg (continuous)
> 890 W/kg (peak)
> Specific energy 5.5 Wh/kg
> Typical DC interface 600 - 750V
> Self-discharge rate 0.5 - 1.0 kW
> Typical Efficiencies at Rated Power
> Motor/generator 98%
> Inverter 95%
> Net one-way 93%
> Net round-trip 86%
> Flywheel Rotor
> General description Composite flywheel rim with
> aluminum hub
> Operating speed range 15,500 rpm - 31,000 rpm
> Polar inertia 0.720 kg·m2
> Energy storage 1,000 Wh @ 31,000 rpm
> 250 Wh @ 15,500 rpm
> Net energy storage 750 Wh
> Motor/Generator
> General description Permanent magnet, 3-phase,
> synchronous, liquid cooled
> Frequency range 515 Hz - 1,030 Hz
> Line-line voltage 230 Vrms at 515 Hz
> 450 Vrms at 1,030 Hz
> Total inductance 100 µH
> Line-
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Author: John LarkinDate: 15:06 10-08-08
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On Sun, 10 Aug 2008 10:17:56 -0700 (PDT), Bret Cahill
<BretCahill@aol.com> wrote:
>If energy from the grid costs 13 cents/kW-hr and a 1000 cycle battery
>costs 27 cents/kW-hr, and diesel is 40 cents/kW-hr, then a 33%
>efficient energy storage device that is capable of thousands of cycles
>over its lifetime suddenly starts to look interesting.
>
>Maybe it's possible to trade a little efficiency for higher energy
>density or lower initial costs.
>
>For example, the flywheel below is 86% efficient but has an energy
>density of only 5.5 W-hr/kg.
But its standby power loss is absurd. That's why they are used as a
short-term UPS sources - if that - rather than as daytime-nighttime
energy movers or vehicle sources.
>
>It would be cost effective to find something that was only 50% or 40%
>efficient but with 10X the energy density.
>
>
Absolutely. If batteries were 10x as dense, and lasted 10x as many
cycles, as they can do now, all sorts of things would change.
Sadly, batteries have to carry all their reactants, and all their
waste, whereas a fuel engine doesn't. And batteries damage themselves
when charged and discharged. And quick charging needs huge power
inputs, with consequential thermal problems; a 50% efficient battery
would cook if you charged it fast.
The ideal battery might use air as one reactant, have its chargable
component refreshed off-vehicle, and dump its wastes. Sure sounds like
a fuel cell to me. Or a gas engine.
John
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Author: Rob DekkerDate: 16:14 10-08-08
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Author: John LarkinDate: 17:42 10-08-08
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On Sun, 10 Aug 2008 13:14:39 -0700, "Rob Dekker" <rob@verific.com>
wrote:
>
>"John Larkin" <jjlarkin@highNOTlandTHIStechnologyPART.com> wrote in
message
>news:p8bu94pft0vnpoh62j67rgvnujsovvpqob@4ax.com...
>....
>>
>> The ideal battery might use air as one reactant, have its chargable
>> component refreshed off-vehicle, and dump its wastes. Sure sounds like
>> a fuel cell to me. Or a gas engine.
>
>Or a Zinc-air battery.
>Which has the additional advantage that it produces no waste.
>
>Rob
>
The vehicle still has to lug around the zinc oxide, which is heavier
than the original zinc. And it has to be collected and reprocessed.
Wiki puts zinc-air fuel cell density at 370 WH/KG. Gasoline is 12,500.
That's 34:1.
John
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Author: Bret CahillDate: 20:45 10-08-08
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> >> The ideal battery might use air as one reactant, have its chargable
> >> component refreshed off-vehicle, and dump its wastes. Sure sounds like
> >> a fuel cell to me. Or a gas engine.
>
> >Or a Zinc-air battery.
> >Which has the additional advantage that it produces no waste.
>
> >Rob
>
> The vehicle still has to lug around the zinc oxide, which is heavier
> than the original zinc. And it has to be collected and reprocessed.
>
> Wiki puts zinc-air fuel cell density at 370 WH/KG. Gasoline is 12,500.
> That's 34:1.
An EV can go 80 miles. A tractor only needs to go one mile.
That's 80:1
2.3 X more energy density than necessary.
Bret Cahill
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Author: Bret CahillDate: 21:00 10-08-08
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> >If energy from the grid costs 13 cents/kW-hr and a 1000 cycle battery
> >costs 27 cents/kW-hr, and diesel is 40 cents/kW-hr, then a 33%
> >efficient energy storage device that is capable of thousands of cycles
> >over its lifetime suddenly starts to look interesting.
> >Maybe it's possible to trade a little efficiency for higher energy
> >density or lower initial costs.
> >For example, the flywheel below is 86% efficient but has an energy
> >density of only 5.5 W-hr/kg.
> But its standby power loss is absurd.
Depends on the application.
> why they are used as a
> short-term UPS sources - if that - rather than as daytime-nighttime
> energy movers or vehicle sources.
But perfect for farm tractors.
Remember, 33% efficiency is now competitive for high cycling energy
storage devices. This number will continue to drop.
> >It would be cost effective to find something that was only 50% or 40%
> >efficient but with 10X the energy density.
> Absolutely. If batteries were 10x as dense,
> and lasted 10x as many
> cycles, as they can do now, all sorts of things would change.
That's not only trivially obvious but also irrelevant to the issue:
Including lower efficiency energy storage devices in a big net search
for higher energy or power density.
Bret Cahill
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Author: Jim PenninoDate: 21:15 10-08-08
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In sci.physics Bret Cahill <BretCahill@aol.com> wrote:
> > >> The ideal battery might use air as one reactant, have its chargable
> > >> component refreshed off-vehicle, and dump its wastes. Sure sounds
like
> > >> a fuel cell to me. Or a gas engine.
> >
> > >Or a Zinc-air battery.
> > >Which has the additional advantage that it produces no waste.
> >
> > >Rob
> >
> > The vehicle still has to lug around the zinc oxide, which is heavier
> > than the original zinc. And it has to be collected and reprocessed.
> >
> > Wiki puts zinc-air fuel cell density at 370 WH/KG. Gasoline is 12,500.
> > That's 34:1.
> An EV can go 80 miles. A tractor only needs to go one mile.
> That's 80:1
> 2.3 X more energy density than necessary.
When the farmer gets out the tractor, it usually runs for hours and
hours under load. The straight line distance isn't a factor.
--
Jim Pennino
Remove .spam.sux to reply.
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Author: Bret CahillDate: 21:23 10-08-08
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> > > >> The ideal battery might use air as one reactant, have its
chargabl=
e
> > > >> component refreshed off-vehicle, and dump its wastes. Sure
sounds =
like
> > > >> a fuel cell to me. Or a gas engine.
>
> > > >Or a Zinc-air battery.
> > > >Which has the additional advantage that it produces no waste.
>
> > > >Rob
>
> > > The vehicle still has to lug around the zinc oxide, which is heavier
> > > than the original zinc. And it has to be collected and reprocessed.
>
> > > Wiki puts zinc-air fuel cell density at 370 WH/KG. Gasoline is 12,500=
.
> > > That's 34:1.
> > An EV can go 80 miles. =EF=BF=BDA tractor only needs to go one mile.
> > That's 80:1
> > 2.3 X more energy density than necessary.
>
> When the farmer gets out the tractor, it usually runs for hours and
> hours under load. The straight line distance isn't a factor.
That was back in the old days _pre_ peak oil.
Things might not be quite so simple post peak oil.
Some are having difficulty accepting what should be a simple concept:
Pre peak: Easy street.
Post peak: Extra labor suddenly becomes cost effective.
Bret Cahill
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Author: Rod SpeedDate: 21:28 10-08-08
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Bret Cahill <BretCahill@aol.com> wrote
>>>> The ideal battery might use air as one reactant, have its
>>>> chargable component refreshed off-vehicle, and dump
>>>> its wastes. Sure sounds like a fuel cell to me. Or a gas engine.
>>> Or a Zinc-air battery.
>>> Which has the additional advantage that it produces no waste.
>> The vehicle still has to lug around the zinc oxide, which is heavier
>> than the original zinc. And it has to be collected and reprocessed.
>> Wiki puts zinc-air fuel cell density at 370 WH/KG. Gasoline is
>> 12,500. That's 34:1.
>
> An EV can go 80 miles. A tractor only needs to go one mile.
Wrong when batterys take so long to charge.
AND what matters is the POWER used, not the distance anyway.
> That's 80:1
Just another stupid irrelevant number plucked from your arse. We can tell from the
smell.
> 2.3 X more energy density than necessary.
Just another stupid irrelevant number plucked from your arse. We can tell from the
smell.
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Author: Rod SpeedDate: 21:30 10-08-08
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Bret Cahill <BretCahill@aol.com> wrote:
>>>>>> The ideal battery might use air as one reactant, have its
>>>>>> chargable component refreshed off-vehicle, and dump its wastes.
>>>>>> Sure sounds like a fuel cell to me. Or a gas engine.
>>
>>>>> Or a Zinc-air battery.
>>>>> Which has the additional advantage that it produces no waste.
>>
>>>>> Rob
>>
>>>> The vehicle still has to lug around the zinc oxide, which is
>>>> heavier than the original zinc. And it has to be collected and
>>>> reprocessed.
>>
>>>> Wiki puts zinc-air fuel cell density at 370 WH/KG. Gasoline is
>>>> 12,500. That's 34:1.
>>> An EV can go 80 miles. ?A tractor only needs to go one mile.
>>> That's 80:1
>>> 2.3 X more energy density than necessary.
>>
>> When the farmer gets out the tractor, it usually runs for hours and
>> hours under load. The straight line distance isn't a factor.
> That was back in the old days _pre_ peak oil.
> Things might not be quite so simple post peak oil.
Wrong, as always. They'll keep doing that using biodiesel, you watch.
> Some are having difficulty accepting what should be a simple concept:
> Pre peak: Easy street.
> Post peak: Extra labor suddenly becomes cost effective.
You're are having difficulty accepting what should be a simple concept:
Pre peak: Easy street.
Post peak: Biodiesel leaves your pathetic little pig ignorant fantasys for dead.
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Author: Jim PenninoDate: 21:35 10-08-08
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In sci.physics Bret Cahill <BretCahill@aol.com> wrote:
> > > > >> The ideal battery might use air as one reactant, have its
chargable
> > > > >> component refreshed off-vehicle, and dump its wastes. Sure
sounds like
> > > > >> a fuel cell to me. Or a gas engine.
> >
> > > > >Or a Zinc-air battery.
> > > > >Which has the additional advantage that it produces no waste.
> >
> > > > >Rob
> >
> > > > The vehicle still has to lug around the zinc oxide, which is heavier
> > > > than the original zinc. And it has to be collected and reprocessed.
> >
> > > > Wiki puts zinc-air fuel cell density at 370 WH/KG. Gasoline is
12,500.
> > > > That's 34:1.
> > > An EV can go 80 miles. ???A tractor only needs to go one mile.
> > > That's 80:1
> > > 2.3 X more energy density than necessary.
> >
> > When the farmer gets out the tractor, it usually runs for hours and
> > hours under load. The straight line distance isn't a factor.
> That was back in the old days _pre_ peak oil.
> Things might not be quite so simple post peak oil.
The requirements of farming haven't changed since humanity howed the
first row.
> Some are having difficulty accepting what should be a simple concept:
> Pre peak: Easy street.
> Post peak: Extra labor suddenly becomes cost effective.
Without tractors most everyone will starve.
Human labor isn't an option. If it were, Africa wouldn't be starving.
--
Jim Pennino
Remove .spam.sux to reply.
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Author: Rob DekkerDate: 21:58 10-08-08
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"John Larkin" <jjlarkin@highNOTlandTHIStechnologyPART.com> wrote in
message news:c0ou94h6skor1kicrp0brqo6eoq0ruc5on@4ax.com...
> On Sun, 10 Aug 2008 13:14:39 -0700, "Rob Dekker" <rob@verific.com>
> wrote:
>
>>
>>"John Larkin" <jjlarkin@highNOTlandTHIStechnologyPART.com> wrote
in message
>>news:p8bu94pft0vnpoh62j67rgvnujsovvpqob@4ax.com...
>>....
>>>
>>> The ideal battery might use air as one reactant, have its chargable
>>> component refreshed off-vehicle, and dump its wastes. Sure sounds like
>>> a fuel cell to me. Or a gas engine.
>>
>>Or a Zinc-air battery.
>>Which has the additional advantage that it produces no waste.
>>
>>Rob
>>
>
> The vehicle still has to lug around the zinc oxide, which is heavier
> than the original zinc. And it has to be collected and reprocessed.
That is correct, but is keeping the zinc oxide in the vehicle a big problem ?
>
> Wiki puts zinc-air fuel cell density at 370 WH/KG. Gasoline is 12,500.
> That's 34:1.
Well, that's kind of comparing apples and oranges.
The battery drives a very lightweight electric motor, at 95% efficiency or so.
The gasoline drives a heavy ICE (+drivetrain/exchaust etc), at 20% efficieny or so (if
you are lucky).
The efficiency factor alone reduces the factor 34:1 to 7:1.
And the motor mass difference could make up for another factor of 4 or so (simple
replace the heavy ICE by battery mass).
So in reality the Zi-air battery should be less than a factor 2:1 off with a gasoline
driven car, and probably at par in many
applications.
Advantage is that the Zi-air technology is very simple.
Disadvantage is of course that an infrastructure has to be put in place to replace and
recycle the Zi-oxide.
Rob
>
> John
>
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Author: Jonathan GrobeDate: 22:23 10-08-08
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On 2008-08-11, jimp@specsol.spam.sux.com <jimp@specsol.spam.sux.com> wrote:
> In sci.physics Bret Cahill <BretCahill@aol.com> wrote:
>> >
>> > When the farmer gets out the tractor, it usually runs for hours and
>> > hours under load. The straight line distance isn't a factor.
>
>> That was back in the old days _pre_ peak oil.
>
>> Things might not be quite so simple post peak oil.
>
> The requirements of farming haven't changed since humanity howed the
> first row.
>
>> Some are having difficulty accepting what should be a simple concept:
>
>> Pre peak: Easy street.
>
>> Post peak: Extra labor suddenly becomes cost effective.
>
> Without tractors most everyone will starve.
>
> Human labor isn't an option. If it were, Africa wouldn't be starving.
>
I believe the author's philosophy is that you operate the
tractor say for a half hour and then spend 5 minutes re-charging
the battery---and that the cost of the tractor operator's
labor spent re-charging batteries is less than the additional cost
you would use with the higher priced fuel (diesel vs electricity).
--
Jonathan Grobe Books
Browse our inventory of thousands of used books at:
http://www.grobebooks.com
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Author: Rod SpeedDate: 22:24 10-08-08
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jimp@specsol.spam.sux.com wrote:
> In sci.physics Bret Cahill <BretCahill@aol.com> wrote:
>>>>>>> The ideal battery might use air as one reactant, have its
>>>>>>> chargable component refreshed off-vehicle, and dump its
wastes.
>>>>>>> Sure sounds like a fuel cell to me. Or a gas engine.
>>>
>>>>>> Or a Zinc-air battery.
>>>>>> Which has the additional advantage that it produces no waste.
>>>
>>>>>> Rob
>>>
>>>>> The vehicle still has to lug around the zinc oxide, which is
>>>>> heavier than the original zinc. And it has to be collected and
>>>>> reprocessed.
>>>
>>>>> Wiki puts zinc-air fuel cell density at 370 WH/KG. Gasoline is
>>>>> 12,500. That's 34:1.
>>>> An EV can go 80 miles. ???A tractor only needs to go one mile.
>>>> That's 80:1
>>>> 2.3 X more energy density than necessary.
>>>
>>> When the farmer gets out the tractor, it usually runs for hours and
>>> hours under load. The straight line distance isn't a factor.
>
>> That was back in the old days _pre_ peak oil.
>
>> Things might not be quite so simple post peak oil.
>
> The requirements of farming haven't changed since humanity howed the
> first row.
>
>> Some are having difficulty accepting what should be a simple concept:
>
>> Pre peak: Easy street.
>
>> Post peak: Extra labor suddenly becomes cost effective.
>
> Without tractors most everyone will starve.
>
> Human labor isn't an option. If it were, Africa wouldn't be starving.
Very little of africa starves. Where they do, its because they
have FAR more kids than their situation can possibly support.
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Author: Jonathan GrobeDate: 22:26 10-08-08
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On 2008-08-11, Rob Dekker <rob@verific.com> wrote:
>
> Well, that's kind of comparing apples and oranges.
>
> The battery drives a very lightweight electric motor, at 95% efficiency or so.
> The gasoline drives a heavy ICE (+drivetrain/exchaust etc), at 20% efficieny or so
(if you are lucky).
>
> The efficiency factor alone reduces the factor 34:1 to 7:1.
> And the motor mass difference could make up for another factor of 4 or so (simple
replace the heavy ICE by battery mass).
> So in reality the Zi-air battery should be less than a factor 2:1 off with a
gasoline driven car, and probably at par in many
> applications.
>
You can't just look at the weight of the drivetrain/exhaust, etc--you have to compare
the weight of the whole ICE car vs the weight of the whole electric car.
--
Jonathan Grobe Books
Browse our inventory of thousands of used books at:
http://www.grobebooks.com
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Author: Jim PenninoDate: 22:45 10-08-08
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In sci.physics Jonathan Grobe <grobe@netins.net> wrote:
> On 2008-08-11, jimp@specsol.spam.sux.com <jimp@specsol.spam.sux.com> wrote:
> > In sci.physics Bret Cahill <BretCahill@aol.com> wrote:
> >> >
> >> > When the farmer gets out the tractor, it usually runs for hours and
> >> > hours under load. The straight line distance isn't a factor.
> >
> >> That was back in the old days _pre_ peak oil.
> >
> >> Things might not be quite so simple post peak oil.
> >
> > The requirements of farming haven't changed since humanity howed the
> > first row.
> >
> >> Some are having difficulty accepting what should be a simple concept:
> >
> >> Pre peak: Easy street.
> >
> >> Post peak: Extra labor suddenly becomes cost effective.
> >
> > Without tractors most everyone will starve.
> >
> > Human labor isn't an option. If it were, Africa wouldn't be starving.
> >
> I believe the author's philosophy is that you operate the
> tractor say for a half hour and then spend 5 minutes re-charging
> the battery---and that the cost of the tractor operator's
> labor spent re-charging batteries is less than the additional cost
> you would use with the higher priced fuel (diesel vs electricity).
A 5 minute recharge, right.
Modern agribussiness doesn't run little, bitty tractors like Eddie
Albert drove around on the Green Acres TV show.
--
Jim Pennino
Remove .spam.sux to reply.
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> > > > > >> The ideal battery might use air as one reactant, have
its char=
gable
> > > > > >> component refreshed off-vehicle, and dump its wastes.
Sure sou=
nds like
> > > > > >> a fuel cell to me. Or a gas engine.
> > > > > >Or a Zinc-air battery.
> > > > > >Which has the additional advantage that it produces no
waste.
> > > > > >Rob
> > > > > The vehicle still has to lug around the zinc oxide, which is
heav=
ier
> > > > > than the original zinc. And it has to be collected and
reprocesse=
d.
> > > > > Wiki puts zinc-air fuel cell density at 370 WH/KG. Gasoline is
12=
,500.
> > > > > That's 34:1.
> > > > An EV can go 80 miles. ???A tractor only needs to go one mile.
> > > > That's 80:1
> > > > 2.3 X more energy density than necessary.
> > > When the farmer gets out the tractor, it usually runs for hours and
> > > hours under load. The straight line distance isn't a factor.
> > That was back in the old days _pre_ peak oil.
> > Things might not be quite so simple post peak oil.
> The requirements of farming haven't changed since humanity howed the
> first row.
The industry has, however.
> > Some are having difficulty accepting what should be a simple concept:
> > Pre peak: =EF=BF=BDEasy street.
> > Post peak: =EF=BF=BDExtra labor suddenly becomes cost effective.
> Without tractors most everyone will starve.
That's why electrification of agriculture is a pretty sure bet.
> Human labor isn't an option.
"Labor" here means some fat guy sitting in an air conditioned electric
tractor.
> If it were, Africa wouldn't be starving.
Even I don't go that far.
Americans did pretty well before the first tractor.
Bret Cahill
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> > >> > When the farmer gets out the tractor, it usually runs for hours
an=
d
> > >> > hours under load. The straight line distance isn't a factor.
>
> > >> That was back in the old days _pre_ peak oil.
>
> > >> Things might not be quite so simple post peak oil.
>
> > > The requirements of farming haven't changed since humanity howed the
> > > first row.
>
> > >> Some are having difficulty accepting what should be a simple concept=
:
>
> > >> Pre peak: =EF=BF=BDEasy street.
>
> > >> Post peak: =EF=BF=BDExtra labor suddenly becomes cost effective.
>
> > > Without tractors most everyone will starve.
>
> > > Human labor isn't an option. If it were, Africa wouldn't be starving.
>
> > I believe the author's philosophy is that you operate the
> > tractor say for a half hour and then spend 5 minutes re-charging
> > the battery---and that the cost of the tractor operator's
> > labor spent re-charging batteries is less than the additional cost
> > you would use with the higher priced fuel (diesel vs electricity).
>
> A 5 minute recharge, right.
The tractor can swap out batteries after every lap and never wait.
> Modern agribussiness doesn't run little, bitty tractors like Eddie
> Albert drove around on the Green Acres TV show.
We really need a tractor pull.
Bret Cahill
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Author: Jim PenninoDate: 23:45 10-08-08
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In sci.physics BretCahill@peoplepc.com wrote:
> > > > > > >> The ideal battery might use air as one reactant,
have its chargable
> > > > > > >> component refreshed off-vehicle, and dump its
wastes. Sure sounds like
> > > > > > >> a fuel cell to me. Or a gas engine.
> > > > > > >Or a Zinc-air battery.
> > > > > > >Which has the additional advantage that it produces no
waste.
> > > > > > >Rob
> > > > > > The vehicle still has to lug around the zinc oxide, which
is heavier
> > > > > > than the original zinc. And it has to be collected and
reprocessed.
> > > > > > Wiki puts zinc-air fuel cell density at 370 WH/KG.
Gasoline is 12,500.
> > > > > > That's 34:1.
> > > > > An EV can go 80 miles. ???A tractor only needs to go one mile.
> > > > > That's 80:1
> > > > > 2.3 X more energy density than necessary.
> > > > When the farmer gets out the tractor, it usually runs for hours and
> > > > hours under load. The straight line distance isn't a factor.
> > > That was back in the old days _pre_ peak oil.
> > > Things might not be quite so simple post peak oil.
> > The requirements of farming haven't changed since humanity howed the
> > first row.
> The industry has, however.
Yep, there's farm machinery with engines that exceed 500 hp now.
> > > Some are having difficulty accepting what should be a simple concept:
> > > Pre peak: ???Easy street.
> > > Post peak: ???Extra labor suddenly becomes cost effective.
> > Without tractors most everyone will starve.
> That's why electrification of agriculture is a pretty sure bet.
Non sequitur.
> > Human labor isn't an option.
> "Labor" here means some fat guy sitting in an air conditioned electric
> tractor.
So extra labor would be two fat guy sitting in an air conditioned
electric tractor for every one you used to run?
> > If it were, Africa wouldn't be starving.
> Even I don't go that far.
"... as many as 38 million Africans are living under the threat of
starvation..."
http://www.un.org/ecosocdev/geninfo/afrec/vol16no4/164food1.htm
> Americans did pretty well before the first tractor.
America had been around for less than 50 years before the first
tractor.
--
Jim Pennino
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