From: jrwalliker@gmail.com   
      
   On 18/12/2025 20:16, john larkin wrote:   
   > On Thu, 18 Dec 2025 19:49:36 +0000, liz@poppyrecords.invalid.invalid   
   > (Liz Tuddenham) wrote:   
   >   
   >> Bill Sloman  wrote:   
   >>   
   >>   
   >> [Lithium batteries    ....again!!]   
   >>   
   >>> More technically, they can go into thermal runaway - they have to get   
   >>> above 120C before they can do it,   
   >>   
   >> How does the sensor monitor every part of the battery?  A small defect   
   >> in a separator could easily heat up to 120C before the temperature of   
   >> the mass of the cell rose noticeably.   
   >>   
   >>   
   >   
   > A microscopic dendrite defect can start an ignition that propagates in   
   > all directions at centimers per second.   
   >   
   >>> so any sensible battery condition   
   >>> monitoring scheme can warn the user long before there much of a risk.   
   >>   
   >> Warning the user isn't much good, the battery technology needs to be   
   >> fail-safe not impending-fail-evident to the user.   
   >   
   >   I once worked with a fire alarm company in Freehold, New Jersey.   
   >   
   > They had a sign on the wall   
   >   
   >    IN CASE OF FIRE RUN, YELL "FIRE"   
      
   I once applied for a job at a company that   
      
   I once applied for a job at a company that made fire extinguishers   
   for putting out explosions.  This involved making a bigger explosion   
   to propel the chemicals that inhibited combustion.  Their products   
   were used in the fuel tanks of various military vehicles and some   
   aircraft.   
   I was put off accepting the post when I discovered how the vacancy   
   had arisen.   
   John   
      
      
   > John Larkin   
   > Highland Tech Glen Canyon Design Center   
   > Lunatic Fringe Electronics   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)