Ethan BrooksBy Ethan Brooks

Updated November 2026

An off grid solar system wiring diagram Australia installers and DIYers rely on shows how panels, a charge controller, a battery bank, an inverter and your switchboard connect. By the end of this guide you will know the correct wiring order, the protection devices each circuit needs, and the Australian standards that apply. Always have final connections checked by a licensed electrician before energising the system.

Understanding the Main Components in the Diagram

Every off grid wiring diagram follows the same basic flow: panels feed a charge controller, the controller charges the battery, and the inverter draws from the battery to supply AC loads. Read the diagram from left to right, with DC circuits on one side and AC circuits on the other. Mark each isolator and fuse as you go, because Australian diagrams typically show them explicitly.

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  • PV array: strings of panels in series, with each string’s voltage kept within the charge controller’s maximum input.
  • DC isolator and fuse: one per string or combined array, placed between the array and the controller.
  • Charge controller: MPPT or PWM, connected to the battery bank through a fused DC cable.
  • Battery bank: with a main DC breaker or fuse close to the battery terminals.
  • Inverter: connected to the battery through heavy-gauge cable and its own DC protection.
  • AC distribution board: inverter output feeds a changeover or dedicated off-grid board.

Wiring the DC Side: Panels, Controller and Battery

Start with the DC side, because it carries the highest currents at low voltage. Connect the panel strings to the controller first, then the battery, so the controller can establish a reference voltage before any load is drawn. Keep DC runs short and use cable sized for the current, not the connector size.

  1. Mount the charge controller and battery in a ventilated location away from direct sun.
  2. Connect the battery bank to the controller through a fused DC cable, with the fuse rated to the controller’s maximum charging current.
  3. Connect each panel string to the controller input through a DC isolator and string fuse.
  4. Confirm the open-circuit voltage of each string is below the controller’s maximum input before closing any isolator.

Wiring the Inverter and AC Board

The inverter connects directly to the battery bank with short, thick cable and a dedicated DC breaker. Its AC output then feeds your off-grid distribution board, where loads are split into essential and non-essential circuits. Keep the inverter’s AC output separate from any mains supply, and never backfeed the grid, which is prohibited under Australian rules.

Connection Protection to include
Panels to controller DC isolator and string fuse
Controller to battery Fused DC cable at the battery
Battery to inverter Dedicated DC breaker
Inverter to AC board AC circuit breakers per circuit, RCD protection

Earthing, Standards and Compliance

Australian installations are governed by AS/NZS 5033 for PV arrays and AS/NZS 4777 for inverter connection. Earthing of the array frame, mounting structure and inverter must follow the standard, and the earthing arrangement should be documented on the diagram. Because compliance requirements are detailed and vary by state, consult a licensed electrician or your state regulator before finalising the design. If you want more background, see 3 Best Solar Power Generator Inverter Options for Home and Off-Grid Use.

A printed or laminated copy of your wiring diagram helps when you are working through each connection and ticking off protection devices. A multimeter lets you confirm open-circuit string voltage and battery voltage before you close any isolator. View on Amazon

Labelled cable ties and heat-shrink markers make it much easier to trace circuits later during maintenance. View on Amazon

Common Mistakes

  • Exceeding the charge controller’s maximum string voltage, especially in cold weather when panel voltage rises.
  • Undersizing DC cable, which causes voltage drop and heat at the battery terminals.
  • Omitting a fuse or breaker close to the battery, leaving the bank unprotected against short circuits.
  • Mixing up battery polarity during connection, which can destroy the controller or inverter.
  • Skipping earthing or RCD protection on AC circuits.

FAQ

Do I need a licensed electrician to install an off grid system in Australia?

In most states, grid-connected and certain off-grid work requires licensed electrical work and inspection. Check your state’s requirements and have the final connections signed off.

Can I use a standard mains wiring diagram for solar?

No. Solar DC circuits behave differently from AC mains, and they require DC-rated isolators, fuses and cable. Use a diagram specifically drawn for PV and battery systems.

Why does the diagram show so many fuses and isolators?

Battery banks can deliver very high fault currents, and PV strings stay energised in daylight. Multiple isolators let you safely isolate each part of the system during maintenance.

Conclusion

A clear wiring diagram turns a complex off-grid system into a sequence of manageable steps. Work from the panels through the controller and battery to the inverter and AC board, and protect every circuit as you go. Review your final design against AS/NZS 5033 and AS/NZS 4777 with a licensed professional before switching on.

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Ethan Brooks

About Ethan Brooks

Ethan Brooks is part of our editorial team and reviews and edits our DIY solar power systems guides, checking product details against manufacturer specifications and owner feedback.