Precision Power D500/1 - Manual (Page 12)

1300W = 108 Amps total current draw
12V
If the same amplifier is driven into a 2 ohm load, double it’s 4 ohm
RMS rating. These amplifiers will effectively double their power at
this load.
1000W X 1.3 X 2 = 2600 watts
2600W = 217 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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