How Beat The High Cost Of Fuel: The ElectraFlyer-C

Dylan Smith wrote:
On 2008-06-24, wrote:
I was looking at one of my sons model aircraft batteries.
a LiPo about the size of a cigarette packet.
the maximim current draw was 54 amps!!!!

Yeah, for a second or so.

Actually, significantly longer. My model helicopter averages about 10
amps in flight and gets about 15 minutes run time off a LiPoly battery
that's half the size of a pack of cigarettes. A LiPoly twice the size
can probably sustain 50 amps for about 6 minutes; you're orders of
magnitude off in your estimate.

Tell you what, put a 54 amp load on the battery you started talking
about, not one twice the size you drifted to, then get back to me
with how long it lasts.


--
Jim Pennino

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"Larry Dighera" wrote in message
...
On Wed, 25 Jun 2008 19:54:33 +0000 (UTC), Dylan Smith
wrote in
:

All the Li-Ion batteries that have burned have had causes, too. (Faulty
charging circuitry in the main).

I wouldn't expect faulty charging circuitry to be the main cause of
lithium batteries spontaneously catching fire.

Here is the cause of the massive Sony battery recall:

http://arstechnica.com/news.ars/post/20060928-7858.html
They cite microscopic metal particles that enter the battery
during the manufacturing process as the reason for the battery
failures. The particles, they say, come into contact with other
parts of the battery cell, causing the battery to short-circuit.
Sony claims that these batteries would normally just power off,
but in "rare cases" may overheat and cause flames.

IMHO, that is far more frightening than charging problems!

Peter

In rec.aviation.piloting Bob Kuykendall wrote:
On Jun 24, 9:45?am, Jim Pennino wrote:

I'm aware of ITER and the fact that *IF* ITER is a success, you can
expect an operational fusion power plant no earlier than 2040, by
which time a good percentage of current posters, including myself,
will be long dead.

I don't see why the long time until payback is an issue. My attitude
is that we've already squandered enough of our grandkids' resources,
the very least we can do is throw them a bone. Comparing the risk/
benefit ratio of ITER with that of other current nonsense like the war
in Iraq, it seems like a no-brainer to me.

The long lead time isn't an issue, it is reality.

Fusion holds the promise of solving a huge percentage of the worlds
energy problems if it can be make to work.

The reality is it will not be before 2040 that the first one goes
into operation, and only then if ITER is a success.

And even if ITER doesn't meet full success, the lessons of its failure
will drive all sorts of different technology innovations.

It is more likely it will drive ITER-B.


--
Jim Pennino

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In rec.aviation.piloting Dylan Smith wrote:
On 2008-06-24, wrote:
Batteries have been under development for well over a hundred years.

But not all batteries are equal.

I have a small radio controlled helicopter. It has full cyclic and
collective pitch controls, tail rotor, etc. It runs off a battery, and
this helicopter would have not been practical just 20 years ago. What
made it practical is the lithium polymer battery, and making the
electronics to control a small but very powerful brushless motor small
enough and light enough. Everything else could have been built 20 years
ago (the main rotor blades are wooden and the PPM receiver is old hat).

It took about 15 years for the LiPoly battery to go from the lab to a
widely available commercial technology. In the lab, they've increased
the LiPoly battery's energy density by an order of magnitude (so based
on past performance, it'll be 15-20 years before we get to see this in
the shops).

Yeah, new stuff gets invented all the time.

Thanks for the news flash, I didn't know that.

The point is electrochemistry is NOT a new field of science and
all the easy stuff has already been done.


--
Jim Pennino

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"Bob Kuykendall" wrote in message
...
On Jun 24, 9:45 am, Jim Pennino wrote:

I'm aware of ITER and the fact that *IF* ITER is a success, you can
expect an operational fusion power plant no earlier than 2040, by
which time a good percentage of current posters, including myself,
will be long dead.

I don't see why the long time until payback is an issue. My attitude
is that we've already squandered enough of our grandkids' resources,
the very least we can do is throw them a bone. Comparing the risk/
benefit ratio of ITER with that of other current nonsense like the war
in Iraq, it seems like a no-brainer to me.

And even if ITER doesn't meet full success, the lessons of its failure
will drive all sorts of different technology innovations.

Thanks, Bob K.

Yes, we can live much better on less.

No, there is not a dire problem as you appear to suppose. In fact the known
petroleum reserves, both in quantity and expected duration are greater than
they were fifty years ago. In addition, as a result of a link in a recent
thread which I cannot currently find, I also read of an experimental
technique using genetically engineered "bugs" to eat waste products and
excerete petroleum. IMHO, there is ample reason to suppose that the
"genetic engineering" merely recreatess something that existed previously
and produced the copeous quantity of petroleum that lies beneath our
planet's surface.

The article about the experiment can be read at:
http://www.timesonline.co.uk/tol/new...cle4133668.ece

Peter

On Wed, 25 Jun 2008 17:56:29 -0400, "Peter Dohm"
wrote in
:

"Larry Dighera" wrote in message
.. .
On Wed, 25 Jun 2008 19:54:33 +0000 (UTC), Dylan Smith
wrote in
:

All the Li-Ion batteries that have burned have had causes, too. (Faulty
charging circuitry in the main).

I wouldn't expect faulty charging circuitry to be the main cause of
lithium batteries spontaneously catching fire.

Here is the cause of the massive Sony battery recall:

http://arstechnica.com/news.ars/post/20060928-7858.html
They cite microscopic metal particles that enter the battery
during the manufacturing process as the reason for the battery
failures. The particles, they say, come into contact with other
parts of the battery cell, causing the battery to short-circuit.
Sony claims that these batteries would normally just power off,
but in "rare cases" may overheat and cause flames.

IMHO, that is far more frightening than charging problems!

Peter

As technology advances and the energy density of batteries increases,
there is a higher probability of more spectacular failure modes.

Here are some more things to think about:

http://en.wikipedia.org/wiki/Lithium_ion_battery
Safety

Lithium-ion batteries can rupture, ignite, or explode when exposed
to high temperature environments, for example in an area that is
prone to prolonged direct sunlight.[40] Short-circuiting a Li-ion
battery can cause it to ignite or explode, and as such, any
attempt to open or modify a Li-ion battery's casing or circuitry
is dangerous. Li-ion batteries contain safety devices that protect
the cells inside from abuse, and, if damaged, can cause the
battery to ignite or explode.

Contaminants inside the cells can defeat these safety devices. For
example, the mid-2006 recall of approximately 10 million Sony
batteries used in Dell, Sony, Apple, Lenovo/IBM, Panasonic,
Toshiba, Hitachi, Fujitsu and Sharp laptops was stated to be as a
consequence of internal contamination with metal particles. Under
some circumstances, these can pierce the separator, causing the
cell to short, rapidly converting all of the energy in the cell to
heat resulting in an exothermic oxidizing reaction, increasing the
temperature to a few hundred degrees Celsius in a fraction of a
second.[41] This causes the neighboring cells to heat up, causing
a chain thermal reaction.

The mid-2006 Sony laptop battery recall was not the first of its
kind, however it was the largest to date. During the past decade
there have been numerous recalls of lithium-ion batteries in
cellular phones and laptops owing to overheating problems. In
October 2004, Kyocera Wireless recalled approximately 1 million
batteries used in cellular phones, due to counterfeit batteries
produced in Kyocera's name.[42] In December 2006, Dell recalled
approximately 22,000 batteries from the U.S. market.[43] In March
2007, Lenovo recalled approximately 205,000 9-cell lithium-ion
batteries due to an explosion risk. In August 2007, Nokia recalled
over 46 million lithium-ion batteries, warning that some of them
might overheat and possibly explode.[44] There was an incident in
the Philippines involving a Nokia N91, which uses the BL-5C
battery.[45]

It is possible to replace the lithium cobalt oxide cathode
material in li-ion batteries with lithiated metal phosphate
cathodes that are not as sensitive to temperature, and so are less
prone to explode. This also extends their shelf life. However,
currently these 'safer' li-ion batteries are mainly destined for
electric cars and other large-capacity battery applications, where
the safety issues are more critical. Unfortunately, a problem with
these 'safer' li-ion batteries is that lithiated metal phosphate
batteries hold only about 75 percent as much energy.[46]

Another option is to use manganese oxide or iron phosphate
cathode.




http://www.batteriesdigest.com/lithium_ion_recall.htm
The Apple recall of Computer Batteries

Lithium-ion batteries in computers were once again voluntarily
recalled in May 2005 when Apple, in conjunction with the U.S.
Product Safety Commission, said that an internal short in three
model notebooks could have battery cells which could overheat and
pose a fire hazard to consumers. Apple received six reports
worldwide of batteries overheating, including two in the United
States.

The batteries are said to be manufactured by LG Chem Ltd., of
South Korea.

The computers were sold through regional resellers, catalogers,
and Apple’s on-line retail stores with batteries from October 2004
through May 2005 for between $900 to $2,300. The batteries also
were sold separately for about $130.

Although Sony and LG chem have provided the bulk of Lithium-ion
batteries for Apple Computer, about 20 percent have been supplied
by DynaPack, a Taiwan-based company. According to an article in
the DigiTimes, DynaPack began shipments to Apple for its
Powerbook earlier this year and Simplo, another Taiwan-based
company will begin shipments to Apple starting at the end of the
year. (“Apple notebook battery recall may benefit Taiwan makers”
by Huang Kung Tien, Taipei; Jessie Shen, DigiTimes.com, 05/25/05)

"Peter Dohm" wrote in message
. ..
but in "rare cases" may overheat and cause flames.

IMHO, that is far more frightening than charging problems!


In "rare cases" entire tanks of 100LL have been known to burst into flames,
even explode! In less rare cases, fuel lines have been know to fail, dousing
the engine area with highly flammable fuel...with predictable results.

Vaughn

Dylan Smith wrote in
:

On 2008-06-25, Bertie the Bunyip wrote:
You mean the refueling accidents? That wasn't spontaneous, they both
had causes, static and wide cut fuel..

One incident I have in mind was a near empty centre tank combined with
an electrical fault - May 1990, Phillippine Air Lines (on the ground,
8 died). There was another one I remember more recently, but I can't
find any information about it (perhaps I've mentally duplicated the
Phillippine Air Lines incident).

Didn't know about that accident. Very interesting. We're only allowed to
burn our center tank down to about 1,000 lbs of fuel. Maintenance empty the
rest occasionally, but mostly we're running around with that much much of
the time due to this concern.


All the Li-Ion batteries that have burned have had causes, too.


Yeah, but not "spontaneous"

Bertie

Andrew Sarangan wrote:



You can add fuel cells to that list too, as a recent development. But
I am sure one could claim that fuel cells are in the Smithsonian
museum as a century-old technology.

Actually, the fuel cell was invented in 1839 so the Smithsonian may
actually have one!

http://www.nuvant.com/education/who.html

Scott

On 2008-06-25, wrote:
Tell you what, put a 54 amp load on the battery you started talking
about, not one twice the size you drifted to, then get back to me
with how long it lasts.

I didn't drift to it -- the original poster said that his son's RC heli
batteries was the size of a cigarette packet. That's twice as big as the
battery for my (presumably much smaller) RC heli.

As an example, a T-Rex 500 heli has a 4 cell LiPoly battery about 3/4
the size of a cigarette packet, and can hover for just under 8 minutes.
At a hover, the T-Rex 500 draws just under 30 amps off that battery. If
you do hard aerobatic stuff with the T-Rex, it can easily draw up to 50
amps and last much longer than 'a second or so'.

The LiPoly batteries we use in RC have *astounding* performance. That's
why LiPoly batteries are used, they have good energy density for a
battery and can supply enormous currents. So long as you don't
overdischarge them, they last well, too. (The ESC in most electric RC
models usually have over discharge protection).

--
From the sunny Isle of Man.
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