When I'm driving down the road with my lights off...they will flicker on and off. I have a 550 watt for my subs and a 200 watt for midrange. I have the proper D-block with fuses... Are these amps sucking too much power from the alternator? I can't understand it because the alternator isnt trying to power the lights and amps at the same time. I know the lights may dim with the stereo on, but mine flicker when the lights are off...Could it be the light switch its self.