Re: Ok i need to know how this all works.
It's actually make more sense to get an better alternator. The reason for this is because when you start your car the alternator is basically what keep the electronics running. You see the battery doesn't put out enough current to keep you car electronics running efficiently, it's the alternator. When the alternator doesn't have enough current to feed the electronics then the current is pulled out of the battery. This may seem all and good but as you pull the current from the battery the voltage of the current gets smaller and smaller. The alternator will try to charge the battery but all of it's current is basically being sent to the electronics, so a lot of stress is put on the alternator (which would eventually cause it to fail).
A yellow top battery would seem like a solution but it is only temporary. In a little bit more time, the battery's voltage would lower too but this time around not only does the alternator have to power the electronics, it also has to power the bigger battery you got there now (causing the alternator to fail even sooner).
Now with a bigger alternator, you can power all your electronics efficiently. With a bigger alternator, the battery will not be needed for a source of current as much since the alternator can handle the load by itself almost.
As for the question if about the subs with the car off. It's basically depends how you do it. If you blast you music for long periods of time with the car off then yes, it bad for the battery. However if you listen to the music as a low to moderate level for not a long time then it's ok. When the car is off so is the alterator, so you basically just draining you battery. If you like to listen to your music with the car off, then you should get a yellow top. The extra power should allow to listen to you music with the car off a little longer with still enough juice to start it. However, you alternator is going to have a lot of work to recharge your battery when you start it.
AOL s/n: Bramab
Current Car: 2006 Jeep Grand Cherokee
Current system (Always under construction):
Head unit: Kenwood DNX5120
Front Dash speakers: 3.5 midrange with DRT-25 Tweets
Front Door speakers: (2) Dayton Reference RS225 8" woofers
Rear Door speakers: Stock Boston Acoustic speakers (mostly faded out for slight rearfill)
Sub amp: JL 1000/1
Speaker amp: Eclipse EA4000
Subwoofer: JL Audio 13W7
Sub enclosure: 2.375 tuned to 30hz