On 3/22/2013 3:23 AM, Keith W wrote:
Daryl wrote:
On 3/22/2013 12:55 AM, Mr. B1ack wrote:
On Fri, 22 Mar 2013 03:00:07 +0000 (UTC), (Bradley K.
Sherman) wrote:
Who are you gonna believe, Boeing or your own lying eyes?
Boeing Co. (BA)'s assertion that U.S. investigators ruled
out a fire within the battery case of a Japan Airlines Co.
(9201) 787 is premature, a National Transportation Safety
Board spokesman said.
Investigators examining the Jan. 7 fire aboard the
Dreamliner in Boston haven't ruled out that flames erupted
within the lithium-ion battery container, Peter Knudson
said today in response to questions about the issue.
...
Michael Sinnett, Boeing's chief project engineer, said in
the briefing that investigators hadn't found evidence of
flames within the Boston battery's container box, an
indication it worked as designed to limit damage from a
battery failure.
A witness who tried to fight the Jan. 7 fire said he saw 3-
inch (7.6-centimeter) flames outside the lithium-ion
battery, and the NTSB has found evidence of high
temperatures within battery cells that failed, according to
preliminary safety-board documents released March 7.
...
http://www.businessweek.com/news/2013-03-15/ntsb-contradicts-boeing-claim-of-no-fire-in-787-battery
--bks
Gawd ... is THIS thread still going on ???????????/
Yes, the 787 is a failure.
Put it this way ... after hearing about its problems *I* will
NEVER fly on one - ever.
And I'm hardly the only one who feels this way.
Not interested in burning to death over the Pacific ....
The conventional Batteries are sometimes called Sealed Lead Acid
Batteries but they are actually AGM batteries.
Modern passenger aircraft normally use Nickel Cadmium batteries
Which are prone to a lot of problems. And it's old tech. Now for the
real negatives. If you overcharge them, they overheat. If you let them
go down below 20% they will need to be taken out and charged very, very
slowly with a special charger. They are very susceptible to temperature
ranges. They are the heaviest of the Non Lead Acid batteries, their
life span is almost equal to the sealed lead acid if you don't count the
fact they damage easy. The cost is more than the AGM.
The AGM is just now finding it's way into the aircraft industry. Of
course, it has been somewhat over looked because of the Lithiums. But
it appears that small aircraft that are worried about initial building
costs are not overlooking them.
What they are looking at is the replacement hours on the Lithiums. They
start out at 800 charges and go to 2000 charges depending on the type of
Lithium. The weights in comparison to the AGM is anywhere 3 times to 5
times lighter. But the cost is at least 5 times the cost.
Less time between
replacements, requires a heated and cooled area but is the most
dependable. If that is all that is keeping the 787 from flying, it's
a pretty simple fix.
Not necessarily as that may need recertification which is a complex and
lengthy since the batteries would be heavier and take up more
space.
They are going to have to be re certified anyway. The AGM isn't that
much larger and it's pretty well proven in the Electric Vehicles to day.
IT does the job if you keep it over 50% just like clockwork and can
last at least 2 to 5 years without going below 50% charge if you keep
them above freezing and below 100 degrees (the same as the Lithiums). I
use AGMs on a daily basis and my battery provider says I am the hardest
on batteries he's ever seen. I am getting ready to do another build
that uses the heavier Deep Cell which is designed to put up with my
punishement. But the AGMs are more rugged than the Lithiums that I also
use.
Nacads also work but for about one run into town before they overheat.
Ever seen a Nacad blow up? IT's pretty anticlimatic. They burst and
make a mess out of everything around it. And it's caustic. Same goes
for a Lithium except they will go into flame and feed the flame until
all the liquid is used up. I have never had a case break open on an
AGM. I've crashed em, dump em, drop em, used them for Rocky Mountain
Offroad, and more.
I can see that the Deep Cell Sealed Lead Acid should be as tough and
have a longer run time but they are twice as heavy. The lifespan of the
Deep Cell the way I use batteries should be as high as the Lithium and
cost less. But the weight means only my 3 wheelers will use them. They
just don't make 10 to 15 amp deep cells. But they do make a very solid
35 amp at twice the weight and size of a 12 amp AGM.
I am just not sold on Lithiums and I am certainly not sold on Nicads.
The Airline Aircraft Industry can use the AGMS and have less problems,
almost the same run time as the lower Lithium Mag batteries and save a
bunch of money.
Daryl