Breathing new life in laptop batteries

From: Dave Dameron <ddameron_at_earthlink.net>
Date: Fri May 7 16:26:16 1999

At 06:43 PM 5/7/99 -0400, Allison wrote:
><The first thing to try is to charge a large electrolytic capacitor
><(say 10000-100000 uF) to about 20V. Now discharge it through the faulty
><cell. If you are lucky, the cell voltage will rise, at which point charge
><the cell as above.
>
>This is the beast bet as cells fail with internal shorts and the cap will
>dump enough energy to open them without cooking the cell.
>
Yes, but many times in my experience another short appears shortly. I have
been watching when recharging a cell treated with the capacitor zap method
and seeing it's voltage go from about 1.3 Volts back to zero again,
sometimes with a faint ping if about completely recharged. Other cells
become leaky electrically so they can be charged, but self discharge in a
few hours. Very annoying. Has anyone seen any writeup on what treatment
causes more of the internal shorts to appear? I.e. continuous trickle
charge, left open circuit, discharge completely, etc.
-Dave
Received on Fri May 07 1999 - 16:26:16 BST