How many DC Acc. can be added?

How much electrical power does the 2006 VTX 1300 S produce? I'm going on a 3,000 mile ride and want to add driving lights, chargers for my cell phone, and for my mp3 player. I've looked for info here but don't see anything specific on this, I did print out the electrical diagram. I usually carry my bike to where I want to ride. There are nine of us from church that are going, most of them have Harleys, or Gold Wings. I will enjoy the trip more if I can see better, keep my phone charged, and tunes playing. Thanks