XPost: sci.electronics, uk.radio.amateur   
   From: ianREMOVETHISjackson@g3ohx.demon.co.uk   
      
   In message <20100914222728.1cb116d5@peterson.fenrir.org.uk>, Brian   
   Morrison  writes   
   >On Tue, 14 Sep 2010 20:03:22 +0100   
   >"Jon"  wrote:   
   >   
   >> very good but if the battery is dead it needs jumpstarting first before it   
   >> will attempt to charge it.   
   >   
   >Yes, the break-in mode on the C9000 is supposed to help recover sick   
   >batteries. So far the jury is out, I think the cells I'm testing are a   
   >bit high on internal resistance so I'm going to disharge them, cycle   
   >them and then recharge.   
   >   
   I have often recovered whiskered-up S/C nicads and equally S/C NiMH   
   batteries by zapping them with a 12V battery charger. I've got a   
   home-made one which will deliver 20A. Apply for a second or two seconds   
   to the dead battery (single cell, correct polarity). With luck, the S/C   
   has gone, and the battery reads 1.3V. Obviously great care should be   
   taken, as there is a small risk that battery might explode. Don't   
   over-do the zapping!   
      
   I then connect a 10A ammeter across the battery, and watch the current   
   drop from typically around 5A, to a trickle.   
      
   I then switch the meter to volts, and note if the voltage is gradually   
   rising. If it is, it is probably rechargeable. If it is slowly falling,   
   the zap hasn't worked. Sometimes another zap is more successful.   
   --   
   Ian   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)