Alright I'm pushing 4 Alpine type rs with a hifonics 2500 Watt amp in a 91 BMW 525i! I have a stock alternater and stock battery! I was wanting to run a second battery like an x's power battery or something like that but idk if my stock alternator will keep them fully charged or if it will do damage to my alternater! I don't have the money to buy a high output alternater so I was gonna throw 2 batteries in my car to stop voltage drops! Do you think this will work! I'm in desperate need of help!