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6k rms, you don't have enough reserve or charging capabilities

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Ok how do you figure the math up?

Nick:

The math is fairly simple. Watts are calculated by multiplying current in Amps times Voltage. 100 amps X 14.7 Volts = 1470 Watts.

The RMS output of an amplifier is basically it's DC power rating. RMS Watts = DC Watts in a sine wave situation. It is close enough for basic calculations with audio output, so we will keep using it.

So, if you have a 200 amp alternator it can make 200 X 14.7 = 2940 Watts. That is a maximum rating, and without enough cooling it will either shut down or melt eventually.

Now for the batteries. 50% discharge is as much as you should push a battery. So if you have a 100 amp/hour battery, you have 50 Ah available. At full charge the resting voltage is 12.65 volts At 50% charge the resting voltage is 12.24 volts. Since the response is fairly linear, we will use the average:

12.65 + 12.24 = 24.89 /2 = 12.445 volts average during discharge. This means that your 100 Ah battery can provide 50 amps x 12.445 volts = 622 watts for one hour, or 1244 watts for a half hour.

Now for the bad news. The amplifier is not 100% effecient. That 6,000 watts RMS has peaks much higher than that, and is probably about 80% effecient. The alternator in your car has other work to do, so you can't use all of that power either.

You can extend your playing time by adding batteries, but it will also extend your charging time. You can add charging capacity (more alternators), but there are limits on space. The best answer is to add both batteries and charging capacity, and to avoid discharging your batteries too deep.

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