I'm moving my boat to a new marina this year and for the first time I'll have my own power and water. At the old marina I shared with four other boats , two of them power boats so the only time I saw power was when I wanted to charge the battery. They would unplug their air conditioning long enough for me get the job done. The question is how can I inexpensively take advantage of this opportunity and power my 12 volt systems (radio , lights) while in port without buying an expensive inverter.