Battery Holder 3$

Although the propeller runs on 3.3V, the prototype board takes 6-9V. Here is a cheap way to get (hopefully) enough battery storage to last all week. I paid barely over $3 to get a new battery holder designed for a Nikon D100 camera (Ebay). It takes 6AA batteries and outputs 6-9V. I like AAs because they are so plentiful. Chances are that you already have some rechargeables kicking around. I like this pack because it is cheap, very well built, and it would be easy to unscrew tabs and solder leads onto them. Here is a nice page that lists information about different batteries: http://en.wikipedia.org/wiki/List_of_battery_sizes This pack of 6 should contain about 18 Watt Hours (NiMH) or 24 Watt Hours (Alkaline). A disposable 9V battery should contain about 5 Watt Hours