From: legg@nospam.magma.ca   
      
   Rechargeable 1.5V lithium batteries are complicated animals.   
   Not a battery, as such, so don't rely on standard battery   
   chemistry descriptions to cover them.   
      
   From tested behaviour:   
      
   There's a real 3.7V lithium cell inside there somewhere, with   
   a charging voltage of over 4V on the battery terminals.Open   
   circuit when charge is terminated internally.   
      
   When it's not being charged, a switching regulator takes over   
   to produce 1.5V on the same terminals, drawing from the   
   lithium cell. This buck regulator is unstable when the battery   
   is not being used, so the battery terminal voltage jumps around   
   if you try to simply measure it.   
      
   I wonder what this does to devices that count on the low noise   
   usually produced by simpler standard cells. Guess I'll find out   
   the hard way. Loaded, the voltage will stabilize, but then you've   
   got normal switching ripple and, supposedly, emc issues.   
      
   Nothing in the literature (?)- it's still the wild west as far as   
   battery products go, in the far east. Currently less than   
   US$1.50 per in low volume retail.   
      
   I lucked into a bunch of rechargeable 9V (PP3) lithiums the other   
   day - furnished with a micro-usb port for charging. Same basic   
   idea, but with a boost regulator supplying the terminal voltage.   
      
   RL   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)