Precision Power DCX 500.1 - Manual (Page 12)

If the same amplifier is driven into a 2 ohm stereo or 4 ohm mono
load, double it’s 4 ohm RMS rating. All
DCX amplifiers will effectively
double their power at this load.
500W X 1.5 X2 = 1500 watts
1500W = 125 Amps total current draw
12V
If you are using more than one amplifier, add up the total current
draw for all of them and choose the appropriate gauge based on the
grand total.
POWER WIRE SIZE
A minimum of 8 gauge or a maximum of 4 gauge wire is
recommended dependent on the application.
The ground wire must be the same gauge as the power wire.
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