Bought 3 Duracell AGM 31s from Sam's. charged them to full 12.6 volts, was out in the garage and turned Pandora on for 1 hour and fifteen minutes which turns on the Sonic Hub module and 1 HDS-7 to control it, I saw the power when I turned it off went down to 12.1, does this seem right for that short time, will be running the 2 HDSs, live well pump, structure scan module and the sonic hub at same time.