We have a 120 volt charger for our laptop but I would like to be able to charge up without going through an inverter. It seems very inefficient to jack the 12VDC up to 120VAC with an inverter and then use a transformer to change back to 20VDC or whatever the laptop needs. Does anyone know of a gizmo that converts directly from 12VDC to 20VDC?
Speaking as an electrician, there are a couple of different circuits you could use to step up 12v dc to 20v. Im not sure how happy your insurance company would be about you installing a homebuilt rig on your boat, but if you were happy about the laptop being fairly static it is totally do-able.