Crux of the energy question
Lynn, you have cut to the heart of the cruiser's energy question. Air and refridgeration are the 2 largest draws of energy aboard. Air uses so much power that it is almost impossible to have large enough batteries to run it for any length of time. For air a generator of a capacity at least as large as the draw of the air conditioner is required. It usually runs on diesel as diesel has the most energy packed inside it of any of the sources available to cruisers.The current thinking (largest amount of new set-ups) on refridgeration, however, is to use 12 volts to drive the compressor motor(s). Batteries are commonly rated in amp hours (ah). The more ah you have, the longer you can run a motor or a light bulb, or whatever. Because of the way they are, you can only use about 1/2 of the battery's capacity before you must recharge it. So basically, you have to have a source of energy, (generator, engine alternator, wind generator, solar panel, or dock side battery charger). A large enough place to store it (battery). And not so much stuff to use it up too soon so that you are charging all of the time, (which would bring us back to a generator again, you have a viable system. An inverter attached to your batteries would make it possible to have 110 volt energy at sea too, but converting 12 volt battery power to 110 uses a lot of battery power in a very short time if you are running something like an air conditioner. Many more intelligent folks than I have written books and articles on this subject. I have tried to distill it down to a few paragraphs to give you the gist. Look at Nigel Caulder's books and articles, contact Jack Rabbit Marine, or ask at your local chandlery about batteries, inverters, loads, and generation. Good luck, I hope this effort at over simplification is of some assistance along your way. READ ALOT! Ron