Here is a size guide for the more common solar PV systems in Australia. Here we have outlined the most common kW size solar panel systems and approximately what size solar battery will offer the best value (or best energy autonomy).

Note that these figures are estimates only, and the right solar battery size for you will always depend on your unique circumstances.

What Size Solar Battery Do I Need for a 3kW System?
For a 3 kW solar PV system with 5-10 kWh daily energy consumption, you can use a 4 kWh battery to maximise returns or a 22 kWh battery to maximise energy independence (and yield about three days of energy autonomy).

For 11-15 kWh daily energy consumption, use a 4 kWh battery. For 16-20 kWh (the average daily energy consumption in an Australian household), you need a 3 kWh battery.

What Size Solar Battery Do I Need for a 5kW System?
For a 5 kW solar PV system with 5-10 kWh daily energy consumption, you need a 4 kWh battery to maximise the returns or a 35 kWh battery to maximise energy independence. For 11-15 kWh daily energy consumption, choose a 7 kW battery.

For 16-20 kWh (the average daily energy consumption in an Australian household), you need a 6 kWh battery.

What Size Solar Battery Do I Need for a 10kW System?
For a 10 kW solar PV system with 5-10 kWh daily energy consumption, you need a 4 kWh battery to maximise returns or a 35 kWh battery to maximise energy independence. For 11-15 kWh daily energy consumption, you need an 8 kWh battery to maximise returns or a 65 kWh battery to maximise energy independence.

For 16-20 kWh (the average daily energy consumption in an Australian household), use an 11 kWh battery to maximise returns or a 90 kWh to maximise energy independence.

What Is kWp in Solar?
kWp stands for kilowatt Peak. It is the nameplate rating of solar PV systems. It refers to the amount of power produced in bright sunshine or under standard laboratory test conditions.

A solar energy professional can give you a customised estimate of the best solar battery size for your unique system, so it’s always best to get an individual calculation performed. However, this gives you a guideline on what size solar battery to consider.

Solar batteries may seem like a de facto great idea, if you have solar panels, a solar battery is great too. Unfortunately, this isn’t the case, and there are a lot of factors to consider. Depending on the location of your home, the direction of your solar panels and your general climate will all affect how efficiently your solar panels work and how helpful a solar battery will be.

If you are unsure if a solar battery is worth it where you live, it’s best to ask for help. Contacting a solar energy specialist will give you a better understanding of whether a solar battery will make its money back and be worth the investment.