It's a touch overkill and perhaps a little OT too, but it does seem the
kind of thing that a few people here will know about.

I managed to obtain an old(ish) APC 5000 Smart UPS (5000VA/3750W) and
wired it into the mains last night. I purely intend the device to
provide backup power and mains cleaning for the boiler, telephone, DSL
modem/router and Wireless AP so it will have a teeny load on it.

Anyway, it has the original lead/acid batteries that came with it, that
seem to still be holding a charge, but they're not great and lose their
charge really quickly. I've pulled one of the batteries out of the
chassis to see if there was any hope of toping it up like a car
battery, but no dice (not that I was suprised).

Does anybody know of a way of 'priming' this type of battery to make it
healthier? Is it worth me charging them up full and then discharging
them as much as possible a few times? Or should I just leave them
constantly charging?

As always, thanks for any and all responses.

Seri