Originally posted by patrickz24
all right let me put it this way,
if you want to play the system when the car if off, then you NEED at least one other GOOD "dry cell" battery.
if you're going to play the system when the car is running, then just get a high output alternator.
I've done both in my case and I'm very happy and as you point it out, better be safe than sorry, specially with a new car.
it's up to you now.
I've tried to avoid this thread, but everyone is telling you the right things! You'll need a dry cell (deep cycle) battery. But this will only minorly help. Since the battery is ONLY made to service the engine! While the caris running the alternator is supposed to be used to power ALL your accessories (including any aftermarket equip. such as radio, amp, TV, etc.). Your best bet is to either goto a scrap yard, pick up an alternator, and have it rewound. I don't suggest using your stock alternator for this, since it will void the warranty, and there is no gurantee on it's lifetime once this is done. However it will usually last awhile if done right. It is even possible to rewind most alternators yourself, they aren't very complicated, do a websearch and you'll find the info.
Or if you have some money, the BEST thing to do is to get a high output alternator. They are usually alot bigger then stock (make sure you have room), but will produce more current at lower rpms. Also when buying or rewinding an alternator, make sure it's done to maximize the current output, and NOT the voltage output. Maximum voltage output means NOTHING for you.
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Also for batteries, consider a 'Recombinant Gas Batteries', it can be trunk mounted, since RG batteries won't vent flammable hydrogen gas or corrosive gasses into the vehicle.
RG batteries also produce the most current possible for it's size. Whereas a deep cycle battery will not produce as much current however it has more reserve capacity.