Those outlets are the only things on your boat that's wired for 110 volts. Everything else will be 12 volts. There are some occasions where one - maybe two - lights would be hardwired into the 110 system but that would more than likely be an aftermarket item installed by a PO.
And no - a battery charger will have no effect on any 110 volt system.
If for some reason your battery grounding wire is loose or corroded then you might have some issues with your 12V system.
Check it for tightness and cleanliness. Do both of them - the battery and the block ground.
