I need to rewire the boat, and it has been widely (and wisely) advised that the first place to start is to figure out my consumption pattern. Is there an easy way to do this by using the demised electrical box on the dock? take a reading on a friday at 5, sunday at five, divide result by two (i thought a two day sample would be more accurate). anyone know 1)if this makes sense and 2)how the heck do i read an electric meter?
Please do not take this the wrong way as I mean it in sincerity and with the safety of you, your crew and your vessel in mind.
If you are asking this question, the way you are, you really should do a LOT more reading on the subject of re-wiring your boat.
We also don't know which consumption you are trying to ascertain? DC consumption? This is the wrong way to go about trying to figure it and one that is not likely to be accurate even if you do all the math including charge efficiency factors, inverter efficiency factors, charger / acceptance factors etc. etc. on and on.
Figuring "consumption" for 110v shore power is rather non-sensical as you size the wiring, over current protection and circuits based on loads. A 30 amp shore power system should be more than adequate for a G-30.
Charlie Wing and Nigel Calder's books are about the best going. I always recommend Charlie's book first as it is more simple and to the point and includes multiple wiring diagrams.
If you don't know how to figure basic consumption, re-wiring a whole boat could be a scary & unsafe process in the end result. Please, please, please educate yourself on marine AC/DC wiring before undertaking this project. Burn down a marina due to non-accepted wiring practices and your insurance company may not stand behind you.. Please be careful!
There are many ways to ascertain DC consumption but the most accurate, because many items are variable consumers, is a battery monitor.
You can also take a guess at hours/use/amps, based on rated amperage of an item, but in the case of a stereo, VHF, refridge, copmputers or other variable consuming items you will still likely have about a 10-15% variance from actual..