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PostPosted: Feb 16, 2007 10:55 am
by hunter
In the end, I don't worry about these safety issues. Caving is a dangerous sport. Taking risks is part of the game. At least I can see what is about to get me. Anyway, having your helmet explode would make a good story....

tagcaver,
that's probably the most honest reply I've ever seen on this board! Thanks for the info. Since I'm paranoid and have had a couple of friends get squashed helmets due to rock fall I think I'll stick with my LEDs for now.
I also agree that having your helmet explode would be right up there at the top of good stories. Maybe your buddies should always carry a video camera, just in case...

Since you mention it, has there ever been an incident of a caver's Sten light pack exploding? I seem to remember these are pretty exposed the way they are normally mounted.

Wow! Great Shot.

Realms, :yeah that:

James

PostPosted: Feb 16, 2007 1:28 pm
by tagcaving
No fires reported that I know of. From the thread below it was determined that the Sten does use lithium ion 18650 cells and where they got them. These have a PTC and PCB board so if handled correctly they should be fairly safe.

http://candlepowerforums.com/vb/showthread.php?t=88744

However, some cavers do not always take care of their gear really well. For example, Lithium batteries do not like to freeze. Leaving them drained in your truck all week in the freezing cold is not good. When you go to charge them after that, you could have a problem. They do not like heat either. Leaving the Sten pack on your dash in the summer can cause them to go into thermal run away, i.e. spontaeously catch fire.

Lithium-ion batteries can easily rupture, ignite, or explode when exposed to high temperatures,[11] or direct sunlight. They should not be stored in a car during hot weather. Short-circuiting a Li-ion battery can cause it to ignite or explode. Never open a Li-ion battery's casing. Li-ion batteries contain safety devices that protect the cells inside from abuse. If damaged, these can also cause the battery to ignite or explode.


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

I am trying to get the word out on this issue as more and more cavers start to use these kinds of batteries. Really, no lie, I store my batteries in my fireplace at home. See for yourself what happens when lithium cells are mishandled...

http://klaudius.free.fr/lipo.htm