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