[quote="omega99, post: 24664"]Minder MKI - what is the purpose of the battery. If the battery was dead & there was a power outage would all the programming be lost?[/QUOTE] There are two batteries. The small CR style on the circuit board. If this is flat and you loose power to the panel your program is gone. The other optional battery is the aux / backup battery 12volt 7ah style which when connected backs up aux powered devices - keypads, PIR's etc if used. this bit is a hangover from the very early (misguided) days of regarding a Minder as a security system. In all the years the number of people who managed to take a Minder and make it perform like a proper security system you could count on a butchers left hand.