[lincpimp]

Use cell phone batteries. Most have a lvc built in, and they come in all sorts of shapes and sizes. They are 3.7v nominal, so 3 of them in series will make an 11.1v pack. Fully charged that is 12,6v. I had some nokia batteries that I was using, and they gave quite a good run time even being 1150mah. I just charged them at .5amp without a balncer and they all charged fine. Sikeston used to sell them prewired, that is where I got mine.