I am trying to get my guitar hero guitar to run on an old cell phone battery and save myself from buying lots of AA batteries. The problem is I need to change the 3.7 volts from the cell phone into 3.0v for the guitar. I calculated that to get 3.0 volts from the cell battery I had add an 89Ω resistance to the battery. I guess I just want to Know if this is at all possible? It would be nice to use some of my junk parts that are laying around.