Claire WhitakerBy Claire Whitaker

Updated November 2026

Off-grid solar system packages with batteries in Australia bundle panels, a charge controller, a battery bank, and an inverter into one kit. This guide walks you through sizing your daily energy use, matching the components, and checking the wiring so the package you buy actually covers your home or shed. By the end, you will know how to read a package spec sheet and spot the gaps before you spend money.

Why Off-Grid Packages Make Sense for Australian Properties

Many rural and semi-rural properties across Australia sit beyond the practical reach of the poles and wires. Connection costs can be high, and some network operators will not extend supply to a block at all. A packaged off-grid system removes much of the guesswork because the components are pre-matched by the supplier. The trade-off is that a package is only as good as its sizing, so you still need to do the arithmetic yourself. Treat the package as a starting point, not a finished answer.

Shopping for one? See our guide: 6 Best DIY Solar Power System Kit Options for Off-Grid Homes (2026). For another angle, check out 5 Best Batteries for Small Solar Panel Options for Off-Grid Projects (2026).

Step 1: Calculate Your Daily Energy Use

Every sizing decision starts with your daily load in watt-hours (Wh). List each appliance, its power draw in watts, and how many hours per day it runs. Multiply watts by hours to get Wh per day, then add everything together.

  1. Check the label or manual on each appliance for its rated wattage. Fridges and pumps often list a running wattage and a higher startup surge.
  2. Estimate daily run time honestly. A fridge runs roughly 8 to 16 hours per day depending on climate and door opening, and a well-insulated 24-hour fridge cycles less than an older unit.
  3. Multiply watts by hours for each device, then sum the results.
  4. Add a 20 to 25 percent margin for losses in the inverter, cabling, and battery charging, plus room for future loads.

A typical off-grid home with a fridge, LED lighting, a laptop, a washing machine used a few times a week, and a water pump might land somewhere between 5 and 12 kWh per day. Your figures will vary, so use your own appliance list rather than any generic number.

Example Load Calculation

Appliance Watts Hours per Day Wh per Day
Fridge (efficient) 80 10 800
LED lighting (6 fittings) 60 5 300
Laptop and router 80 6 480
Water pump (average) 400 0.5 200
Washing machine (averaged) 300 0.7 210
Total 1,990 Wh

Add a 25 percent margin to 1,990 Wh and you get roughly 2,500 Wh per day. That figure drives everything that follows.

Step 2: Size the Solar Array

Australia receives strong solar irradiance, but the amount varies by region, season, and panel orientation. A common planning approach is to assume about 4 to 5 peak sun hours per day as a conservative average across much of the country, then adjust for your specific site. Divide your daily Wh by peak sun hours and by a system efficiency factor (commonly around 0.75 for a DIY setup) to find the array size.

Using the example above: 2,500 Wh divided by 4.5 sun hours and then by 0.75 gives roughly 740 W of panels. A 800 W to 1,000 W array would give you a comfortable margin, especially in winter. Check the panel specs on any package to confirm the rated wattage and the number of panels included.

Step 3: Choose the Battery Bank and Chemistry

The battery bank stores your energy for nights and cloudy days. Lithium iron phosphate (LiFePO4) is the most common choice in current packages because it tolerates deep cycling and holds more usable capacity than lead-acid of the same nominal size. Lead-acid (flooded, AGM, or gel) costs less upfront but needs more capacity to deliver the same usable energy and typically has a shorter life.

To size the bank, multiply daily Wh by the number of days of autonomy you want (often 1 to 2 days), then divide by the usable depth of discharge. For LiFePO4, a usable depth of 80 to 90 percent is typical. For lead-acid, 50 percent is the usual planning figure.

Example: 2,500 Wh times 1.5 days, divided by 0.9 for LiFePO4, gives roughly 4,200 Wh of storage. At 12 V that is around 350 Ah, or about 3.5 kWh in a 48 V bank using 100 Ah modules. Many packages in Australia use 24 V or 48 V battery voltages, so confirm the voltage matches the inverter and charge controller.

Step 4: Match the Inverter and Charge Controller

The inverter converts battery DC into the 230 V AC that most Australian appliances expect. Its continuous rating must exceed your combined running load, and its surge rating must handle motor startup. A common approach is to choose an inverter with a continuous rating at least 25 percent above your highest expected simultaneous load.

The charge controller regulates power from the panels into the batteries. An MPPT controller is the usual choice because it extracts more energy from the array than a PWM unit, especially when panel voltage is well above battery voltage. Check that the controller’s maximum input voltage and current suit your array configuration.

Step 5: Check the Wiring and Protection

Wiring is where many DIY builds run into trouble. Use cable sized for the current, keep DC runs short, and fit fuses or circuit breakers at the battery, near the inverter, and on each solar string. Australian installations involving grid-connected work or fixed wiring may require a licensed electrician, and off-grid DC work still carries serious shock and fire risk at battery voltages. If you are unsure, consult a licensed professional before connecting anything.

  • Victron Energy MPPT charge controller: Widely used for DIY off-grid builds, with a monitoring app that helps you check real charging performance. View on Amazon
  • Multimeter with DC clamp: Lets you verify open-circuit voltage, check string current, and test for leakage during commissioning. View on Amazon
  • Victron Energy battery monitor: Tracks state of charge and current flow so you can compare your actual use with the sizing estimate. View on Amazon

Common Mistakes

  • Sizing the package from the panel wattage alone and ignoring your actual daily load.
  • Forgetting startup surge from pumps and compressors when choosing the inverter.
  • Mixing battery voltages or chemistries in one bank.
  • Undersizing cable, which causes voltage drop and heat.
  • Assuming winter performance matches summer output.

Tips for Getting the Most from Your Package

Log your real consumption for two or three weeks before you commit to a larger system. Keep the array unshaded and tilted toward the equator at an angle near your latitude for better winter output. Set battery cut-off and low-voltage alarms so the system protects itself. Expand modularly by adding panels or batteries later, provided the controller and inverter have headroom.

FAQ

What is included in an off-grid solar system package with batteries?

Most packages include solar panels, a charge controller, a battery bank, an inverter, mounting hardware, and cabling. Some add a battery monitor or a generator input. Always check the spec sheet to see which items are actually supplied.

Is LiFePO4 better than lead-acid for Australian off-grid use?

LiFePO4 generally offers more usable capacity, longer cycle life, and lighter weight. Lead-acid can still suit low-budget or intermittent use, but it needs more capacity and regular maintenance in many cases.

How many days of battery backup should I plan for?

One to two days is a common planning range. Properties with reliable sun may manage on one day, while those in cloudy regions or with winter-heavy use often choose two.

Can I run a washing machine on an off-grid package?

Often yes, but the surge and daily energy use matter. Check the inverter’s surge rating and the washer’s energy per cycle, and consider running it during peak sun hours. If you want more background, see Off-grid Solar System Cost Australia: A Step-by-Step Budget Guide.

Do I need a licensed electrician?

Requirements vary by state and by the type of work. Consult a licensed electrician before connecting any system to fixed household wiring, and check local regulations for off-grid installations.

How long do off-grid batteries last?

Lifespan depends on chemistry, depth of discharge, temperature, and charging practice. Manufacturers typically specify cycle counts at a given depth of discharge, and those figures are the best starting point for comparison.

Can I add more panels later?

Yes, as long as the charge controller can handle the higher input voltage and current and the inverter has enough headroom. Confirm both limits before expanding.

Conclusion

A good off-grid solar system package with batteries starts with an honest measurement of your daily energy use. Size the array, battery bank, inverter, and controller from that number, and check the spec sheet against your calculations before buying. Careful wiring and protection will keep the system safe and reliable for years.

Ready to choose one?

Claire Whitaker

About Claire Whitaker

Claire Whitaker 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.