Re: Stereo Question
To calculate the current draw of an amplifier, multiply the number of channels by the RMS watts per channel (a 4 channel amp rated at 150 watts RMS per channel would be 600 watts). Double it to account for amplifier inefficiency.
(600 watts X 2 = 1200 watts), then divide by the average output Voltage of an alternator, 13.8 volts (1200 divided by 13.8 = 87 amps). Since the average music signal requires about 1/3rd of the average power in a test tone, divide by 3 (87 amps divided by 3 = 29 amps). The result is the amplifier's approximate average current draw.
Though your amp implies 600w I wouldn't really count on it putting that many watts out RMS. the 600w indicated is more of a marketing ploy. To answer your question, an accurate current draw would need to be figured into the equation.
A quick way to ballpark an amplifier's current draw is to divide the total fuse value of the amp by two. For amplifiers with multiple fuses, the rating of all fuses provided with the amp must be added together. This will likely produce a significantly higher estimate than using the proper formula. Although inaccurate, this will err on the side of safety.
Finally, compare the amplifier's approximate current draw to your reserve current capacity to determine if the electrical system can support the amplifier.
