> I also immediately apply nominal charging current
> right after the zap - usually by using a suitable
> current limiting resistor in series with the 20 V
> charging supply. This resistor also serves to
> limit the charging current of the cap when the
> 20 V supply is turned-up.

An alternative to zapping is that you can apply a high
(eg 15V) voltage to the cell while keeping a very close
eye on a voltmeter. The cell will sit there for a short while,
perhaps a few seconds, perhaps a minute, soaking it up
until the voltage across it will rise suddenly. That's a good
time to take the 15V away very quickly;-)  Hopefully the
cell should take a normal charge after that. If this technique
doesn't work, zap it

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