48Vインバーターケーブルサイズ

How to use this calculator

1. Choose the system voltage (12, 24 or 48 V) and enter the load or inverter power in watts.
2. Enter the one-way cable length and the maximum voltage drop you accept (often 2–3%).
3. Click Size the cable for the current, the minimum cross-section and the closest standard size.

Why low-voltage DC needs thick cable

At low voltage the current is high for the same power, and even a small drop is a large percentage. The cross-section comes from the copper resistivity, the round-trip length and the allowed drop:

Because the current doubles when the voltage halves, a 48 V system needs far thinner cable than a 12 V system for the same power.

Current for 2000 W by system voltage

Keep battery-to-inverter runs as short as possible and terminations clean and tight — most low-voltage faults are loose, hot connections.

よくある質問

What size cable for a 48V inverter?

Work out the current (power ÷ 48 V), then size the cross-section for your run length and a 2–3% drop. A 3000 W 48 V inverter draws about 63 A and typically needs 16 mm² (≈6 AWG) for a short run.

Why does a 12V system need such thick cable?

For the same power, 12 V draws four times the current of 48 V, and the allowed voltage drop in volts is tiny — so the cable must be much larger to keep losses down.

What voltage drop should I allow on DC?

Keep battery and inverter cables to about 2–3% drop. Lower is better on the main battery cables, where high current makes any resistance costly.