Howard Winter wrote:

> I had a couple of 12V 80Ah batteries that were fine when I left
> them, but after a couple of years' inattention are completely useless -
> reading about 7V.  Even a "recovery" battery charger doing a
> "desulphate" cycle can't make them hold a charge.  

This is consistent with what the link says that Gus posted. They say that
after a few months of (partial) discharge, the sulfation goes into what
they call level 3, which may or may not be possible to be removed by
electrical means.

With the self-discharge, your batteries probably stood longer than a few
months partially charged.

> Conversely, some 6V 100Ah Yuasa "Endurance" batteries that were treated
> just the same were showing over 6V each, and with a half-hour top up
> charge were pronounced "Strong" by the charger. [...] To be fair,
> Yuasa's "Endurance" range is designed more for long-term storage than
> deep cycling [...]

I wonder what these batteries have that makes them seemingly less
susceptible to sulfation.

Gerhard

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