Tested two old (the newer one is 11 years old) originally 4.5 amp hour 6 volt rechargeable batteries, by connecting 'em up to 12 watts of lighting & waiting. They should both have been pretty well fully charged.
1. Lasted 2 1/2 hours, which is good. Either the lights are drawing slightly less than they're supposed to, or the battery has slightly more capacity than it was originally rated at.
2. Nothing. Zilch. Nada. I can't get it to light anything up. I plugged everything it failed to light up into 1), & they all worked. Oh dear. It was lighting things up last week, though one of the things it was lighting up was a battery low indicator, much earlier than expected (hence the test).
In case it wasn't actually charged up, I'm now recharging 2), & I'm doing it with the charger I used for 1) (the batteries are the same make, same type) in case it's the charger.
This battery may be heading for the recyclers.