Backwoods Home magazine has a series of articles that provide some good basic solar power and battery power information. The series is ongoing, so there is more to come.
These articles are applicable to off-grid or grid-supported systems, regardless of whether the dwelling is fixed or mobile.
Basic Solar Information
http://www.backwoodshome.com/articles2/yago72.html
Basic Battery Power Information, Part I
http://www.backwoodshome.com/articles2/yago87.html
Basic Battery Power Infortmation, Part II
http://www.backwoodshome.com/articles2/yago88.html
Solar Power 101: Inverters
http://www.backwoodshome.com/articles2/yago89.html