I had to buy a new battery for my SC400 after letting it sit for four months. I had the alternator tested at the time and it was fine. I did have the common PS leak, but it was not from the pump (I fixed it by cleaning the filter). The car ran perfect for two months. It completly shut down yesterday. I took the battery back to Advance Auto and got a new one. They told me the battery was not dead, just depleted. When I started the car the battery light was on. I took it to Advance and they said the Alternator was bad. When I started it today the battery light was not on, and the car ran perfect. Do you guys think it is an alternator problem, or the fact that I just bought a cheap battery? I bought my jet ski batteries from them too, and they only lasted a season.