How a home power station works.
About home solar batteries
What is a solar battery?
A solar battery is where the energy from the solar panels is stored. Solar panels generate energy while the sun is shining, the unused solar electricity is stored in an energy storage device installed in your home (the battery). This battery can help power your home when the panels aren’t producing electricity, such as during the evening or on overcast days.
Whether battery storage is right for you, and which kind, depends on what you want it to achieve. Below are general examples of the benefits of having solar storage.
Cutting your energy bills.
With energy bills increasing in recent years, it makes sense to look at ways to reduce costs. Save money on your electricity bills by charging your battery from your excess solar.
Any solar energy you generate will reduce emissions from fossil fuel generation, whether you use it yourself or export it to the grid. By generating solar energy, you are turning to clean renewable energy.
Power in a power outage.
Most batteries can provide backup during power outages. However, it’s important to note that not all batteries can operate independently if the network goes down. So be sure to do your research.
Many people buy a battery as insurance against potential future energy price rises. You may also wish to rely less on your electricity retailer or network. The ability to store energy allows you to be less dependent on the grid for additional power.
Sell excess energy.
Solar batteries allow you to store, control and maximise your ability to use the electricity you generate, even when the sun doesn’t shine. With a battery, you may be able to earn money by participating in emerging energy systems, like virtual power plants.
Supporting the local grid.
Support your local grid and earn extra money by selling power back to the grid when it’s needed the most.
Choosing a home solar battery.
What to consider?
Choosing the right battery storage size for your needs depends on the size of your solar system, how much energy you consume during the early morning or overnight, whether you want backup during a power outage and your financial considerations, including budget. See below for tips on what to think about when considering a battery.
Making the most of your solar.
Calculate your excess solar energy per day and decide whether you would like to store all excess solar or just enough for the evening peak.
Powering your house overnight.
Calculate your sunlight hours and overnight energy use. Size your solar and battery so the battery can be fully charged during the day and discharged at night.
Having backup for outages.
Design your system like an off-grid setup, with a special inverter and isolation switch. Plan for a larger system with higher costs and less efficient battery utilisation.
Understand the battery’s maximum discharge rate, because this will determine how many appliances can be run off the battery at the same time.
Get a battery that has easy to use software and lets you control the system and check performance.
Lifespan and warranty.
Check whether the warranty refers to years, cycles or other limitations like ambient temperature. You’ll want your battery to last as long as the warranty and beyond.
Will a home solar battery save you money?
Things to consider.
There are a range of factors to consider when deciding whether you would financially benefit from a home solar battery system. Some of these include:
The ‘payback period’ is the time it takes for a battery to pay for itself with savings in your energy bills. In some cases, a solar battery system may not pay itself back before the warranty ends.
Choosing an appropriately sized battery for your needs will achieve the best economic return. Depending on your requirements, the payback time is generally quicker for a small battery, when paired with a new solar system. The best way to choose the right size battery is to consult an expert.
Consumption and tariffs
If you have higher than average electricity consumption (more than $2,000 per year), are on a time of use tariff, and are planning on installing a new solar system, it could make financial sense to install a solar battery system.
In a rural area where electricity is more expensive, a solar battery could help reduce your energy bills. Sunnier inland locations also tend to pay back one year quicker than coastal locations.
Solar export to the grid.
If you have, or want to install, a large solar system and the grid is limited by how much excess solar you can export, a battery may be a good option.
Future battery costs.
Battery costs are expected to continue to decline over the next few years, which will reduce payback times.
Estimating your payback period.
To estimate the payback period in years, divide the upfront system cost by the projected annual savings in your energy bills. If you have a warranty that is less than the payback period, the battery system may not pay for itself before the warranty expires.
New solar without battery.
A new rooftop solar system, without a battery, usually has the shortest payback period.
New solar and new battery.
Installing a new solar system with your new battery usually has the shortest payback period of the battery options mainly due to the solar system.
Addition of battery to existing solar.
Adding a battery to existing solar, also called retrofitting, has a longer payback period than new solar and new battery, often exceeding the warranty period. While this option may not pay for itself, it still improves your energy self-sufficiency.