From: jl@glen--canyon.com   
      
   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"   
      
      
   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)