Hi, I'm working on a project to build a solar powered AA battery charger. This is definitely not my profession, I only have a small understanding of electrical engineering. Mostly from what I learned in high school electrical class. Here is what I'm looking to do: I want to charge 16 AA batteries. There will be 2 sets of batteries. 8 (series) AA, connected in parallel. If your are wondering why they are in parallel, ultimately this will be used to charge a tablet, so I want to up the capacity. If you are wondering why I don't buy one... They don't make one. So I have a few questions: 1) To charge a battery, I need to hook it up backwards, that is I hook the positive of the power source to the negative of the battery, and the Negative of the power source to the positive of the battery. Right? 2) How much voltage do I need to put through this to charge the batteries? 3) How difficult would it be to make this charger prevent over charging?