I bought a Portalac PXL12072 UPS battery (12v/7.2Ah) sealed lead acid battery from a local shop, but I just noticed the date engraved on the battery seems to be more than a year ago (so it could be 'old stock'). The voltage is still good (12+ volts) when tested at the shop using multimeter.
Since I don't have a dedicated sealed lead acid battery charger, I just placed it inside the UPS and let it charge for more than 24 hours (with no load attached to the UPS). After it was fully charged (I hope more than 24 hours should have fully charged the said battery), I was curious to test its capacity, so I used the EBD-USB+ load tester to test it (set it to 0.2C or 1.20A, which according to the spec sheet lasts around 4-5 hours, with a cut-off voltage of 9.6v or 10.2v -- I'm not sure if I'm reading the spec sheet correctly...) Spec sheet listed here: http://www.gsbattery.com/ml-pxl-series/PXL12072 and http://www.gsbattery.com/electrical-lighting-pe-px-pxl-series
But anyway, the load/capacity test result graph:
Based on the load test graph, is this battery still good?
(I notice the voltage has already dropped below 12.0v at around 3000mAh capacity output.)
I'm not sure up to what cut-off voltage does a UPS designate as 'discharged'.
From previous batteries - when still in good condition, assuming a load of around 100watts or less, the UPS would last around 5 or so minutes (with the previous batteries, haven't tested it yet with this new one)
(Are the correct terms for the UPS batteries "valve regulated lead acid batteries" VRLA? How about the proper terminology for the lead-acid batteries for automotive start-up batteries?