The Merits S538/S548 is a Mobility system that requires a 12V 12Ah AGM replacement battery. The compatible Universal Power Group replacement is the UPG UB12120 12V 12AH F2 AGM Battery (UB12120), a 12V 12Ah AGM sealed lead-acid battery. This battery delivers up to 144 watts of standby power. It weighs 8.16 lb, uses F2 terminals, measures 6 L x 3.8 H in, and has left polarity. This is a direct drop-in replacement for the Merits S538/S548 requiring no modification to the device.
