I have a 2000 also cant get the gauge to above 11, everything looks okay bought an optima battery conditioner, both blue tops are up to 13.2 v but gauge is still low, and yes i"m running amps and tower speakers, it seems to drop dramatically when i kick on blower drops to 10-11. nav lights drop it a bit too. I have 2 batteries and selector switch when were surfing i have it to both batteries and floating listening to music i manually switch it to 1?????? I pulled the alternator and took it to a shoo they tested it and said it was fine? Boat starts and runs good, but I don't think its charging correctly any thoughts please share???? Im confused?