Sérénité has both AC and DC power systems. The AC system is powered when we're in port connected to shore power, the DC system is connected to the battery bank that is charged by the engine, wind generator and shore power. Currently, the primary means of charging the battery bank is the shore power connection via the battery charger. Someday soon I'll be installing a solar array that will take over this job, but for now I'm reliant on the power grid. Many of Sérénités's primary systems such as navigation, refrigeration, lights, heat, water, etc. all rely on the DC system, so when it stops working it's a huge problem - that's what I awoke to.
The problem turned out to be the battery charger, at some point during the night it had stopped charging the battery bank. So I pulled the unit, disassembled it - ignoring the "Do Not Open, No User Serviceable Parts Inside" warning on the cover, and proceeded to repair it. The culprit turned out to be a blown fuse on the circuit board. Why the manufacturer put it there instead of somewhere more accessible I'll never know! :-/ I modified the unit by adding an external fuse holder to make the fuse easier to replace next time, reassembled the unit, reinstalled it with a new fuse and applied power - it booted up and began functioning per spec. Yay!! Just saved several hundred bucks :-)