How to Wire an Inverter in a Campervan
Installing an inverter in a campervan allows you to run mains-powered appliances from your leisure battery. This guide explains how to wire an inverter safely, how to choose the correct cable size and where to place fuses for reliable 12V and 24V campervan electrical systems.
Campervan inverter wiring diagram
Quick wiring overview
A campervan inverter connects directly to the leisure battery using short, heavy-duty DC cables. These cables must be sized correctly to handle high current safely.
- Battery positive → fuse → inverter positive
- Battery negative → inverter negative
- Cables should be as short as possible
- Fuse must be installed close to the battery
Why inverter cable size matters
Inverters draw high current from the battery, especially at 12V. Even a small inverter can require significantly thicker cable than normal accessory circuits. Undersized cable can cause voltage drop, overheating and inverter shutdown.
Use the Cable Size Calculator to estimate the correct cable size before installation.
Typical inverter cable current examples
| Inverter size | Approx current at 12V |
|---|---|
| 300W inverter | ≈ 25A |
| 600W inverter | ≈ 50A |
| 1000W inverter | ≈ 85A |
| 2000W inverter | ≈ 170A |
Higher current means thicker cable is required. Always calculate based on your exact inverter size and installation length.
Optional supporting diagram
Where to place the inverter fuse
The fuse protects the cable between the battery and inverter. It must be installed close to the battery positive terminal.
Estimate fuse size using the Fuse Size Calculator.
Voltage drop and inverter performance
Voltage drop becomes critical with inverter wiring. If voltage drops too far under load, the inverter may shut down early even when the battery still has charge remaining.
Check voltage loss using the Voltage Drop Calculator.
Recommended cable type for campervan inverters
Flexible battery cable or welding cable is normally used for inverter installations because it handles high current and vibration well.
Typical inverter wiring mistakes to avoid
- Using cable sized only by fuse rating
- Mounting the inverter too far from the battery
- Installing the fuse too far from the battery
- Ignoring voltage drop
- Using accessory cable instead of battery cable
Tools to help size inverter wiring correctly
Use the calculators below together for the best result.
Start with the calculator
The easiest way to size campervan inverter cable properly is to calculate it first, then check voltage drop and fuse protection.