Yes, I've done the big three. My biggest concern is that when I drive home or for an extended period (1+ hours) I drain everything that's in the battery. So when I go to start it after the trek it's dead.
I was blessed with having the largest alternator VW provided for the 2.0L Jetta. Looks like a 180amp version would be roughly $400 plus cost to install. I figured wiring a secondary battery (KHC-2000?) in the trunk would resolve my issues. I would wire it so that it would only pull power from the main battery with two fuses and another part that I'm not too sure on.
This happened to me first off what sizes are the fuses on each amp you run?
2 you need a high output alternator from what I hear your runnin the same wattage I am a 250 amp alternator will suit your needs and just find an optima yellow top that fits your group size for your car youll be good , from what I read
Your battery and alternator are bad , your alternator I giving out low output and your car and system are all running of your battery you need to un hook your amps ASAP until you get a new battery and high output alternator or you will regret what you do to your car good luck