A Flicka 20 owner details his energy budget, battery bank, and cabin lighting and fan choices.
One of the best resources on the web for familiarizing yourself with sailboat boat electrical design, techniques and materials.
Sells and installs a wide range of electrical equipment. Site has good general information about many electrical components and short "reference" pages on related topics. Also sells and installs a wide range of electrical equipment.
One vendor's 72-page explanation of the components of an on-board energy system, the calculations that you can use to define it, and much of the data you need to make it balanced and economical. Despite promoting the company's WhisperGen, this is probably the most educational reference on the web.
These people do custom design, installation and troubleshooting of electrical systems. Their site has a useful collection of FAQ's on various components of a marine electrical system. Some of the items are manufacturer-specific.