my 2c worth, i had a voltage sort-of guage on 1 of my airplanes few years back, it had (i think) 7 digital light indicators 3-green, 2 yellow, & 2 red, i used it on a JR 1800mha 4-cell pack, i guess thats a 4.8 volt pack, you might check some really good eletronics parts store, the 1 down the street from me has every gaget, gismo, & really strange things i ever saw. Why not bone up on what you want & build it! there's a web site www.how stuff works.com that has everything from atomic energy to how ball point pens work, when i have some idle time, i go there just confuse myself:mex:
