I have a good question for everyone. I have a 2001 Focus and have a Rockford Fosgate 800 watt mono amp and everytime the music hits real hard it makes the odometer light dim and the headlights dim just a little. My question to everyone is if I were install a cap would that solve the problem or would i have to install a cap and a new battery also. I dont have any idea on what to do because i want the problem fixed but i dont want to have to spend a boat load of money doing it and if i wait a lot longer im afraid that my alternator is going to burn up. So if anyone has any feedback at all it would be greatly appreciated.