ok so I just picked up a 02 mcs and Im planning on fitting it out with a complete system fairly soon but Im not sure if the alternator will hold up to it and also if the trunk has enough space for what I would like to do. What I would like to do is a 13" W7 with a alpine pdx1.1000 running it and the pdx4.100 running the speakers, but for one Im not sure if there is enough space to give a 13" the room it needs and for two Im not sure if the alternator could hang with that kind of power out put.

 

The 13W7 requires slightly under two cubic feet for a sealed enclosure. You can easily fit that in the back of a MINI - the question is whether you'll be satisfied with the amount of space left over.

As for the alternator, that would depend on how loud you're going to play the system, and for how long. The alternator doesn't have to be able to supply the *peak* current draw from the system - only the *average* current draw. If the combined peak draw from the car's electrical systems (including the stereo) is more than the alternator can supply, that just means that the rest of the current will come from the battery, temporarily discharging it. As soon as the current draw drops down, the alternator will charge the battery back up. You're only in trouble if the *average* current draw is too much for the alternator to provide. If this is the case, then the battery will drain over time, since the alternator can't provide both the current required for the car's electrical systems AND the current required to re-charge the battery.

If you've got a 1400W system, the theoretical *peak* current draw for the stereo is about 200A (assuming 14V from the alternator and a 50% efficiency rating for the amp(s)). This does NOT mean that you need a 200+ amp alternator, though, because the *average* current draw will not be anywhere near 200 amps. The only way you could see a 200-amp draw for more than a millisecond or so would be if you played a test tone continually at full volume.

Even if you can find out the capacity of a stock alternator, it's not going to do you any good unless you also know the average current draw from all of the car's electrical systems (ECU, running lights, fans, ignition, etcetera). You would also have to know what the average current draw from your stereo will be, and that's hard to calculate without some pretty sophisticated test equipment.

Make sure you get a new, high-current battery, and give it a try. If you end up with a dead battery after a few days, then you'll either have to upgrade the alternator, reduce your gains, or take it easy with the volume ****.

 

Where does one get said High-Current battery? I also plan on upgrading my stereo i plan on running a 5/500 JL amp should i worry about it? would it hurt if i bought a cap? or would that be a waste of money?

 

Caps do you no good if your alternator can't supply the average current demands of the car's electrical system. Remember, a capacitor doesn't generate any current on its own - every bit of energy that comes *out* of the capacitor had to be put *in* there by the alternator. So, if the alternator can't keep up, adding a capacitor won't help.

The main reason I suggested a high-current battery for the original poster is that his car is a 2002 - if he still has the stock battery, or even a factory-style replacement, he may have significant internal resistance in the battery that will cause the voltage to drop if the battery has to supply a large load.

As far as where to get high-current batteries, the Optima "Red Top" is a good choice, and both Stinger and Kinetik make some as well.