[mikegett]

Circuit City was correct. 500 watts shouldn't be enough to drain the electrical. How old is your car? If your vehicle is over three years old then the battery could be poor. The bad thing is that a poor battery will kill your altenator as well. I strongly suggest any individual have there battery and alt tested prior to spending the money on a system. Battery and altenators (installed by you) will easily cost close to 300 dollars. If you have a lack of funds,you can always wait on the system. If your electrical system fails then you are screwed. I bought my alero brand new and had to replace the battery after one year. I will also add that the alero is the first out of four delco altenators that has lasted three years for me. I have very little faith in there products. If you do buy a new alt, then get a guality aftermarket.