Here are some good battery links for testing batteries:

• How do the battery testers on battery packages work?
  http://www.howstuffworks.com/question423.htm
  
• Testing Batteries:
  http://www.vencon.com/index.php?page=support_art1
  
• Battery Testing For Photovoltaic Applications :
  http://photovoltaics.sandia.gov/docs/battery1.htm/
  
• Information on batteries:
  http://www.batteries101.com/