On the topic of chargers and lighting, I'm was an electrician in the Navy and should know this, but don't:
My first night on my boat (last December), I checked my charger because ... well, long story full of problems. The point is, my 120-12 volt converter is putting out amps, but the voltage output is only 10 volts. I don't understand: in order to charge the batteries -- which it does seem to be doing -- doesn't the voltage output have to be greater than that of the batteries, which varies at times between 12 and 14 volts?
Am I an idiot ... or a big idiot?
My other related question on lighting is this: I am a liveaboard and need more lighting. Should I install 120 volt since I am always on marina-paid shore power when in port; or should I install more 12 volt so that, when sailing, I can use it? Advise anyone.