I recently came into posession of a Sony BP-2 sealed lead acid battery. It is 17 years old, still factory sealed and has never been opened. Presumably the plates are covered with crystalized sulfides after all this time even though it was stored fully charged to begin with.
The battery is 4 volts 500 ma. Does anyone know if there is a small pulse charger reconditioner out there appropriate for this? I've seen several schematics for simple ones but don't have the time to take to build one. I'd rather buy a commercially available desulfator or pay someone for a home made one.