This article provides some great information on setting up a small low voltage DC solar system. Although the article is aimed primarily at off-grid cabins and the like it is sure to be useful information for the permaculturist. Working in many remote places and attempting to utilize as much on-site energy production and conservation as possible this article will give you good insights into small scale solar DC power.

http://backwoodshome.com/articles2/yago116.html