On Nov 12, 9:29*pm, Mike the Strike wrote:
I remember fun days working in a lab where colleagues were developing
the "revolutionary" sodium sulfur battery (colloquially referred to as
the "fire and brimstone" battery). *The chief skill developers learned
was how to run fast while wearing asbestos suits and full-face
protective helmets. *If you've never had to deal with a bucket of
burning molten sodium, you've never lived! *(Hint - water isn't
terribly useful!) *You probably wouldn't want any quantity of burning
(molten or otherwise) lithium near you or in your glider either.

Lithium is WAY too close to the reactive end of the periodic table
(right up there with sodium, magnesium and potassium).

MIke

Mike,
I have no problem with considering Li-Ion's to be unsafe and to have
no place in a glider, but I don't understand having that opinion and
then flying with 1 to 3 of them. That was why I burned up an Ipaq
battery, to see if they are too small to cause a problem. My
conclusion is that anything from 800 mAH or larger, and probably
smaller, will make a glider uninhabitable.

But perhaps a better way of getting a handle on the risk is to look at
the incident rate, said to be about 100 cell phones fires between 2002
to 2004, out of more than 200 million cell phones are in use. This is
consistent with a fire risk of something like 1 in 4 million per year
of use for 'good' batteries and 1 in 200,000 for defective ones.

Laptop fires:
There were two recalls, the first of 9.7 million laptops after 16
fires, the other of under 6 million after 50 fires. This was for
defective units with metal particles that internally shorted out the
battery.

More info he
http://www.consumeraffairs.com/news0...#ixzz157SfeqzG

and he
http://www.buchmann.ca/article28-page1.asp

Really I am not trying to convince anyone that Li-Ions are safe, I
thought it would be helpful to have a discussion about them. The most
valuable fact for me was the existence of the 15AH lead acid unit.

Brian