Mine runs the same. 12.6-12.8 on my smart craft gauges. Over on BBC there is a thread that the Mercury Gurus are talking about it. They said that they should only be reading 12.6
That's weird! How well does a battery recharge with that little of a surplus? Even at 14 volts with the load our pumps, electronics, poles, ect put on the battery I am surprised we don't have more battery problems. Cranking plates, iirc, weren't made for constant cycles in charging.