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The danger of electronics

R

Roger Hamlett

Jan 1, 1970
0
Jan Panteltje said:
Fire official: Man's cell phone apparently sets him ablaze:
http://edition.cnn.com/2007/US/01/15/cell.phone.fire.ap/index.html
Almost certainly the battery, rather than the 'electronics'. There were a
number of cases a little whle ago, of 'clone' batteries (and some genuine
ones), that if mechanically distorted, could short internally. When you
discharge the energy in modern cells quickly the temperatures involved can
be really dangerous. Even worse, on Lithium based cells, once they
rupture, if moisture is present, you then get the chemical action as the
Lithium re-acts. Many years ago, large Lithium cells were used in some kit
in TV studios. I was present one day, when one started to smoulder. It was
not doing much harm, till somebody decided to throw a bucket of water over
it. Clouds of really hot steam. The fact the man was in the bathroom, may
suggest a similar scenario with water...

Best Wishes
 
R

Roger Hamlett

Jan 1, 1970
0
Eeyore said:
Why do ppl insist on wearing such flammable clothes made from plastics ?
Agree wholeheartedly.
Worse, they do it in enviroments more dangerous than this. If you try to
source fire retardant cotton overalls, in the UK, many places look at you
as if you are 'mad'. You see people working in garages, wearing
poly-cotton, even sometimes cose to people welding...

Best Wishes
 
M

mpm

Jan 1, 1970
0
If I remember correctly, one of the reason these batteries can be so
dangerous is that during combustion, they create their own oxygen
source. This can make the fire very difficult to put out, perhaps
nearly impossible using ordinary means.

I recall reading an article on this very subject recently (EE Product
News, I think?) that was questioning whether these batteries should be
allowed aboard commercial aircraft. The incident of battery ignition
is indeed quite low, but it that environment could prove catastrophic.
I don't think the general public really understands just how dangerous
these devices can become - under the wrong circumstances.

But I guess people wouldn't eat fast food behind the wheel (put on
make-up, read a book, etc..) if they understood the forces involved in
motor vehicle accidents either... Let's just hope the victim here
makes a speedy recovery! And incidentally, never throw water on molten
metal fires. Bad idea!

-mpm
"Jan Panteltje" wrote in message:
There were a number of cases a little whle ago, of 'clone' batteries
(and some genuine
 
D

Dmitri

Jan 1, 1970
0
Jan Panteltje wrote:



Fire official: Man's cell phone apparently sets him ablaze:
http://edition.cnn.com/2007/US/01/15/cell.phone.fire.ap/index.html

I think we'll see more of these kinds of accidents in the future. This one
is second in the last year if I'm not mistaken (Sony laptop batteries
being the first). As Li-ion batteries become less of a high-end power
source and more of a commodity more OEM manufacturers will start
manufacturing those and some less controlled ones are bound to have
quality problems go undetected. I think if you bought a Li-ion battery on
the aftermarket of grey market, you are in danger.

As far as managing the risks, however, you still have a better chance to
get hit by a bus than to become torched by your cell phone.
--

Best Regards,
Dmitri Abaimov, RCDD
http://www.cabling-design.com/
Home Cabling Guide, Cabling Forum, color codes, pinouts and other useful
resources for premises cabling users and pros



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J

Jan Panteltje

Jan 1, 1970
0
Almost certainly the battery, rather than the 'electronics'. There were a
number of cases a little whle ago, of 'clone' batteries (and some genuine
ones), that if mechanically distorted, could short internally. When you
discharge the energy in modern cells quickly the temperatures involved can
be really dangerous. Even worse, on Lithium based cells, once they
rupture, if moisture is present, you then get the chemical action as the
Lithium re-acts. Many years ago, large Lithium cells were used in some kit
in TV studios. I was present one day, when one started to smoulder. It was
not doing much harm, till somebody decided to throw a bucket of water over
it. Clouds of really hot steam. The fact the man was in the bathroom, may
suggest a similar scenario with water...

Best Wishes

Sometimes I have 2 or even three celphones, and a digital camera in my pockets,
all with high power batteries.
This really made me think twice, maybe better carry that stuff in a carrying
case.
Did not know about the water danger.....
Flammable night clothes are forbidden from selling here IIRC, dunno
about other clothing.
 
R

Rich Grise

Jan 1, 1970
0
Why do ppl insist on wearing such flammable clothes made from plastics ?

1. They're cheap.
2. Who expects a telephone to start a fire?

Cheers!
Rich
 
T

Terry Given

Jan 1, 1970
0
Rich said:
1. They're cheap.
2. Who expects a telephone to start a fire?

Cheers!
Rich

you forgot:

3. most people havent a clue about what there clothes are made of, let
alone whether or not its flammable. this could be abbreviated to: most
people havent a clue....

Cheers
Terry
 
J

Jan Panteltje

Jan 1, 1970
0
you forgot:

3. most people havent a clue about what there clothes are made of, let -----------------------------------------^^^^^
alone whether or not its flammable. this could be abbreviated to: most
people havent a clue....

Yea, but most people get along somehow in a world full of things they
have not much of a clue about sometimes.

As a neural net [we are] errors are inherent, even if we have done something
1000 times, we still have a good chance of doing it wrong.

When every body is replaced by silicon [robots], still cosmic rays will cause glitches.
So the robot world is not perfect either.
You cannot know everything, so get used to the subset ;-).

Note to self: No useful data, do not post it.
<hits button>
 
W

Wim Ton

Jan 1, 1970
0
mpm said:
If I remember correctly, one of the reason these batteries can be so
dangerous is that during combustion, they create their own oxygen
source. This can make the fire very difficult to put out, perhaps
nearly impossible using ordinary means.

Sort of, the reaction gets its oxygen from water (if present) or air
These light metals react violently with water, producing heat, hydrogen gas
and a metal hydroxide. It was one of the spectaculair demonstrations in the
chemistry lessons :) till health and safety regulations probably forbid it
:-(
I recall reading an article on this very subject recently (EE Product
News, I think?) that was questioning whether these batteries should be
allowed aboard commercial aircraft. The incident of battery ignition
is indeed quite low, but it that environment could prove catastrophic.
I don't think the general public really understands just how dangerous
these devices can become - under the wrong circumstances.

Imagine someone breaking up his laptop lithium battery and throwing it into
the aircraft's toilet....If the effect is not sufficient, he can ignite the
resulting hydrogen gas, preferably after waiting till the optimal
hydrogen/oxygen ratio is reached.

Wim
 
T

Terry Given

Jan 1, 1970
0
Jan said:
you forgot:

3. most people havent a clue about what there clothes are made of, let
-----------------------------------------^^^^^

alone whether or not its flammable. this could be abbreviated to: most
people havent a clue....


Yea, but most people get along somehow in a world full of things they
have not much of a clue about sometimes.

As a neural net [we are] errors are inherent, even if we have done something
1000 times, we still have a good chance of doing it wrong.
indeed.


When every body is replaced by silicon [robots], still cosmic rays will cause glitches.
So the robot world is not perfect either.

I was intigued to learn (many years ago) that big GTO drives must be
designed to handle half-bridges turning on, as cosmic rays can (and do)
trigger them, regardless of the gate drive.
You cannot know everything, so get used to the subset ;-).

Note to self: No useful data, do not post it.
<hits button>

LOL.

Cheers
Terry
 
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