All about batteries

Image source: Clean Energy Council

When the sun is shining, you use free electricity, saving you the retail cost of electricity. When you’re using energy stored in your battery, you save the retail cost of electricity, but you are no longer receiving the feed-in-tariff for this energy, since you are storing it in your battery and using it yourself. While you’re using battery electricity, you’re saving the cost of retail electricity minus the feed-in-tariff.

Image source: NSW Government Solar System Factsheet for Households and Businesses

When the battery is empty, your electricity will be drawn from the grid. You'll receive electricity as usual, at retail electricity prices. And when the sun is shining and your battery is full, you can still feed excess energy into the grid and receive the feed-in-tariff.

A standard solar and battery system may not provide power during a blackout. The system automatically shuts off to protect the power lines, and anyone working on them during an outage, from electricity being fed into the grid. Batteries can be configured with additional hardware to provide backup supply during a power outage. If this is important to you, tell your battery retailer.

To make use of a battery, your solar system needs to generate more than you use, and you need to use electricity when the sun isn’t shining, for example in the evenings.

Contact Solar Savers or a reputable solar and battery supplier, who can look at your energy bills and help you decide whether a battery makes sense for you, and what size battery is right for your home.

Batteries can be added to a solar system later, but some additional components may be needed, even for a ‘battery-ready’ system.

Choose a Clean Energy Council Approved Battery to ensure you can access any available rebates, and your battery meets Australian standards. The same considerations for choosing a solar company apply. Batteries are typically expected to last around ten years, and this is the length of a typical battery warranty. For most batteries, performance is reduced over time, and after ten years can be 60-80% of the original, although some types of batteries can be higher. Check the product details for the battery’s ‘end of life’ capacity.

To determine if a battery is going to save you money over its lifetime, consider the payback period – the time it will take for your energy bill savings to equal the upfront cost of the battery. Payback periods can vary depending on the battery you choose, your solar capacity, and your energy use. 

The Clean Energy Council and CHOICE have more information on choosing a battery system. The NSW Government has also released a guide to batteries for homes in NSW, and while some sections are specific to NSW, much of the information about selecting a battery is relevant to Victorian households.