Electrically Powered Ultralight Aircraft

Ken Finney wrote:
"Gig 601XL Builder" wrDOTgiaconaATsuddenlink.net wrote in message
...
Gig 601XL Builder wrote AND THEN HIT THE SEND KEY BEFORE HE MEANT TO:
GM on the cutting edge of anything is a little funny. And I'm sure
Sony didn't think their batteries would do this...
http://www.youtube.com/watch?v=WeWq6rWzChw



Is this the story you are talking about John? If so what is an "LG
Chem cell?"
http://www.autobloggreen.com/2007/06...gm-awards-two-
battery-development-contracts-for-chevy/


GM doing this also kind of proves my point that the new battery
technology is coming from somewhere with a lot more money in play
than the ultralight and LSA market.



"LG" is Lucky Goldstar, a Korean conglomerate.

So it is just another version of a Li-Ion battery and not a "new"
technology?

"Gig 601XL Builder" wrDOTgiaconaATsuddenlink.net wrote in message
...
Ken Finney wrote:
"Gig 601XL Builder" wrDOTgiaconaATsuddenlink.net wrote in message
...
Gig 601XL Builder wrote AND THEN HIT THE SEND KEY BEFORE HE MEANT TO:
GM on the cutting edge of anything is a little funny. And I'm sure
Sony didn't think their batteries would do this...
http://www.youtube.com/watch?v=WeWq6rWzChw



Is this the story you are talking about John? If so what is an "LG
Chem cell?"
http://www.autobloggreen.com/2007/06...gm-awards-two-
battery-development-contracts-for-chevy/


GM doing this also kind of proves my point that the new battery
technology is coming from somewhere with a lot more money in play
than the ultralight and LSA market.



"LG" is Lucky Goldstar, a Korean conglomerate.

So it is just another version of a Li-Ion battery and not a "new"
technology?

Yes. GM is also working with another company, A123, on their
"nano-phosphate" technology, but it is just a different flavor of Li-Ion.

Ken Finney wrote:
"Gig 601XL Builder" wrDOTgiaconaATsuddenlink.net wrote in message
...
Ken Finney wrote:
"Gig 601XL Builder" wrDOTgiaconaATsuddenlink.net wrote in message
...
Gig 601XL Builder wrote AND THEN HIT THE SEND KEY BEFORE HE MEANT
TO:
GM on the cutting edge of anything is a little funny. And I'm sure
Sony didn't think their batteries would do this...
http://www.youtube.com/watch?v=WeWq6rWzChw



Is this the story you are talking about John? If so what is an
"LG Chem cell?"
http://www.autobloggreen.com/2007/06...gm-awards-two-
battery-development-contracts-for-chevy/


GM doing this also kind of proves my point that the new battery
technology is coming from somewhere with a lot more money in play
than the ultralight and LSA market.



"LG" is Lucky Goldstar, a Korean conglomerate.

So it is just another version of a Li-Ion battery and not a "new"
technology?

Yes. GM is also working with another company, A123, on their
"nano-phosphate" technology, but it is just a different flavor of Li-
Ion.

So what makes them think that these are going to be any less likely to
explode than the others? I think Toyota is taking the right path holding off
on the battery powered cars. Let GM eat the first thousand or so lawsuits.

"Gig 601XL Builder" wrDOTgiaconaATsuddenlink.net wrote in message
...
Ken Finney wrote:
"Gig 601XL Builder" wrDOTgiaconaATsuddenlink.net wrote in message
...
Ken Finney wrote:
"Gig 601XL Builder" wrDOTgiaconaATsuddenlink.net wrote in message
...
Gig 601XL Builder wrote AND THEN HIT THE SEND KEY BEFORE HE MEANT
TO:
GM on the cutting edge of anything is a little funny. And I'm sure
Sony didn't think their batteries would do this...
http://www.youtube.com/watch?v=WeWq6rWzChw



Is this the story you are talking about John? If so what is an
"LG Chem cell?"
http://www.autobloggreen.com/2007/06...gm-awards-two-
battery-development-contracts-for-chevy/


GM doing this also kind of proves my point that the new battery
technology is coming from somewhere with a lot more money in play
than the ultralight and LSA market.



"LG" is Lucky Goldstar, a Korean conglomerate.

So it is just another version of a Li-Ion battery and not a "new"
technology?

Yes. GM is also working with another company, A123, on their
"nano-phosphate" technology, but it is just a different flavor of Li-
Ion.

So what makes them think that these are going to be any less likely to
explode than the others? I think Toyota is taking the right path holding
off on the battery powered cars. Let GM eat the first thousand or so
lawsuits.

They don't so much explode, as burn. One of the thingsthat many don't
realize is that a "battery", by definition, is made up of cells. One bad
cell tends to take out other cells around it and damage the battery. So, if
your reliability goal is "1 in 1000 battery failures" and you have 1000
cells in each battery, you actually need a cell failure rate of less than "1
in a million". I'm willing to drive a car with Li-Ion batteries, I can run
away from the fire. Ford experimented with Sodium-Sulphur batteries years
ago, pretty difficult to run away from one of those fires. On the other
hand, I've personally had a car with a gasoline engine catch on fire, so
their failure rate isn't zero.

"Ken Finney" wrote

Yes. GM is also working with another company, A123, on their
"nano-phosphate" technology, but it is just a different flavor of Li-Ion.

Close, but not quite accurate.

The common lithium ion battery outgases oxygen in the process of burning,
which then feeds conventional fires and helps consume the other cells.

The 123 batteries are a different chemistry that do not outgas oxygen, thus
do not catastrophically fail.
--
Jim in NC

Are
you able to provide links to any forums or web sites related to this


Check this out: http://www.calcars.org/news-archive.html

David Johnson

On Aug 10, 5:12 pm, Dave wrote:
Are

you able to provide links to any forums or web sites related to this

Check this out:http://www.calcars.org/news-archive.html

David Johnson

Lithium Polymer batteries are widely used in RC planes, cars, etc and
are known to be potentially dangerous. Most runaway fires occur during
charging but it has also occurred to a lessor degree during discharge
and even storage. Vented charging safety bags are recommended for this
reason. There is a video on this link that shows the explosive power
of small LiPo's. Consider the size differance of these batteries to
the one hung under the trike in one of the first posts or those that
could be installed in the wings of a sailplane.
http://www.liposack.com/video.html

On Sat, 11 Aug 2007 06:59:02 -0700, wrote in
.com:


Lithium Polymer batteries are widely used in RC planes, cars, etc and
are known to be potentially dangerous. Most runaway fires occur during
charging but it has also occurred to a lessor degree during discharge
and even storage.

I would assume that the source of these Li-ion Polymer battery fires
is excessive electrical current flowing through the battery either
from too high a charging rate, too high a discharge rate, or a short
internal (as in the case of the Sony laptop cells) or external, or
being over charged. Perhaps it would be prudent to install a circuit
breaker of fuse to prevent too high a current and a timer to
disconnect a forgotten charger.

Vented charging safety bags are recommended for this
reason. There is a video on this link that shows the explosive power
of small LiPo's. Consider the size differance of these batteries to
the one hung under the trike in one of the first posts or those that
could be installed in the wings of a sailplane.
http://www.liposack.com/video.html

Thank you for the link. It is spectacular.


Here are some links relevant to the Sony Lithium laptop battery
recall:

Story: http://www.theinquirer.net/default.aspx?article=32550
http://news.com.com/Dell+takes+heat+...3-6105828.html

Video:
http://www.youtube.com/watch?v=WeWq6...lated&search=#

Explanation of cause:
http://reviews.cnet.com/4660-10165_7-6625980.html
http://www.prnewstoday.com/release.h...H05424082006-1
The recall arises because, on rare occasions, microscopic metal
particles in the recalled battery cells may come into contact with
other parts of the battery cell, leading to a short circuit within the
cell. Typically, a battery pack will simply power off when a cell
short circuit occurs. However, under certain rare conditions, an
internal short circuit may lead to cell overheating and potentially
flames. The potential for this to occur can be affected by variations
in the system configurations found in different notebook computers.

The thing that strikes me most in this thread is that so many people
just don't seem to understand...

1) weight

2) power

3) scale

Please keep in mind that there are many lithium ion and lithium polymer
chemstries. It isn't too informative to just say "Lithium Polymer" or
Lithium Ion" without stating the precise chemistry. Further, chemistries
are changing almost daily. Many are proprietary. There's no such thing as
a "standard" lithium battery chemistry.

Valence, Saft and A123 Systems use chemistries that are far safer than the
relatively inexpensive Korean made model airplane batteries - safer than the
typical laptop or cell phone battery which are spec'd mainly on price.

Interestingly, the safest chemistries in the latest cells also offer faster
charging, greater energy density and will endure a FAR greater number of
charge cycles. They're also potentially cheaper.

I've already made a cell holder for A123 Systems "A1" cells. That's the
lithium phosphate nano cathode one used in 36V DeWalt power tools. You can
buy a couple of new DeWalt 36V power packs for $50 or so on Ebay. Then,
dismantle the pack to retrieve the individual cells. My pack will be 13.8
volts and 11AH weighing 3 pounds. It will be the same size as a 7AH 12V SLA
but weigh less than half as much.

Bill Daniels

Some Lithium cells can suffer thermal runaway and fire. Others are
extremely
wrote in message
oups.com...
On Aug 10, 5:12 pm, Dave wrote:
Are

you able to provide links to any forums or web sites related to this

Check this out:http://www.calcars.org/news-archive.html

David Johnson

Lithium Polymer batteries are widely used in RC planes, cars, etc and
are known to be potentially dangerous. Most runaway fires occur during
charging but it has also occurred to a lessor degree during discharge
and even storage. Vented charging safety bags are recommended for this
reason. There is a video on this link that shows the explosive power
of small LiPo's. Consider the size differance of these batteries to
the one hung under the trike in one of the first posts or those that
could be installed in the wings of a sailplane.
http://www.liposack.com/video.html