How Many Amps Does a 3,000 Watt Inverter Draw?

Answer
278 A at 12 V (full load)

Battery amps = watts ÷ (battery volts × inverter efficiency). At full load a 3,000 W inverter draws 278 A at 12 V, 139 A at 24 V or 69 A at 48 V (90% efficiency).

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PF
1.0 for heaters and lights; 0.8–0.9 for motors.
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How we calculated this

    For estimating and educational purposes only. Results are approximate and are not a substitute for a licensed professional, the manufacturer's instructions or your local code. Disclaimer

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    3,000 W inverter: current, fuse and cable

    BatteryFull-load currentFuse (125%)Copper cable (75 °C)
    12 V278 A350 A500 kcmil
    24 V139 A175 A2/0 AWG
    48 V69 A100 A3 AWG

    The calculator above uses the input power: 3,000 W ÷ 0.9 = 3,333 W. Keep battery cables short (under 10 ft) or size up for voltage drop. Follow the inverter manual for fuse and cable sizes.

    Frequently asked questions

    How long will a 100Ah battery run a 3,000 W inverter?

    About 19 minutes at full load on a 12 V LiFePO4 battery.

    Should a 3,000 W inverter be 12 V or 24 V?

    24 V or 48 V halves or quarters the current, allowing thinner cables. Above about 2,000 W, 24 V or 48 V is recommended.

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