Free wiring tool
Wire Size Calculator (12V / 24V / 48V)
Undersized wire is the most common mistake in DIY solar, and the most dangerous one. Enter your current, your cable run, and your system voltage. This tool hands back the AWG gauge that keeps voltage drop in check, plus the fuse size to protect that wire. Prefer a printable reference? See the DC wire-gauge chart.
How to use this
- Find the amps. For simple DC loads, divide watts by your system voltage. A 600W load on 12V is 50A. For the battery-to-inverter run, do NOT use that shortcut: tick the inverter box below and enter the inverter's continuous watts, and the tool will size from real worst-case current (low battery voltage plus conversion loss).
- Measure the one-way distance from source to load. The tool doubles it for the full circuit.
- Pick 3% drop for solar charge lines and sensitive electronics. 5% is acceptable for short feeder runs to lights or pumps.
Your circuit
For simple DC loads: watts ÷ volts = amps. A 360W panel array on 12V pushes about 30A.
Source to load along the actual cable path, not as the crow flies.