My question is what's the best way to run this system in a 2002 chrysler concorde lxi?

Question

I have two memphis 1000ds, 4 cerwin vega 12 in hed subs, and a 500 watt memphis cross over. I wanted to use a cap but a friend said an extra car battery is better(is that true?).

Answer 1

Untrue. Unlike a battery, a capacitor can be charged to near the alternator's output of 14.4 volts. That means when the voltage starts to drop, the capacitor can immediately help provide reserve power. A battery is limited to its maximum charge voltage of around 12.8 volts, so it doesn't do anything to help the system until the voltage has dropped to that point.

In most systems, second batteries aren't helpful unless you intend to play the system for long periods without the engine running. When the engine is running, they're just an extra load on the alternator.

Depending on how you plan to use the system, you may need to upgrade your alternator, as well as the wiring between the battery and alternator, battery and chassis ground, and the engine block and chassis ground. This can help prevent power loss through factory wires.

How do you have a "500 watt" crossover? Active crossovers don't generally have wattage ratings.

Answer 2

Running a second battery is never a good idea as it's just an added strain on the alternator. A cap is only good so far as the audio system isn't trying to pull too much from the electrical system.

I know a cap can be beneficial as I'm running one and I measured a definite change in my electrical systems response curve to big bass hits with an oscilloscope, however, this won't be the case for ALL vehicles. Especially with a high current draw.

If your total system power is more than 1000 watts RMS you will need to:

1. Upgrade the alternator to a high output alternator
2. Upgrade to a heavy duty deep cycle battery
3. Upgrade the "Big 3" - that is to replace the power wire between the battery and alternator, the ground from the battery to the chassis and the ground strap from the engine/tranny to the chassis with at least 1/0 AWG wire.

Failure to do this will result in you replacing them anyway as the alternator will eventually fail. You can implement a cap after you've upgraded the alternator if you want for better voltage stability.

Here is a guide that will calculate what size alternator and power wires you need http://www.datafilehost.com/download.php?file=6d26c621

You'll need Microsft Excel to use it.

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