I notice that my voltage guage level dips sometimes when i use my blinkers or have my hi and low lights on. When my door is open i also notice my lights inside the cab go dim when i do this too. I need some general guidence on where to start. My truck has a sound system in it with 3 amps and 2 10 inch subs and a couple dvd players. Could this be drawing to much power? I thought of adding a second battery but its a little pricy for me right now. Any suggestions?