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How do solar batteries work? The basics of solar-powered battery storage

As residential solar power continues to gain popularity, curiosity about the inner workings of solar batteries, which are the storage backbone of this renewable energy, is also rising. If you’ve ever wondered how solar-powered batteries work, you’ve landed in the right spot. Here’s a high-level explanation of their basic functions.

Understanding solar batteries

Solar batteries, or solar energy storage systems, are devices designed to store for later use the surplus electricity generated by the solar panels on your home. They’re pivotal in squeezing out the utmost efficiency from your solar energy set-ups because they let you tap into the electricity your panels have generated, even when the sun isn’t shining.

And, as the Federal Department of Climate Change, Energy, the Environment and Water says, “recent design improvements and price drops in lithium-ion batteries have made solar storage more viable than ever before”.

How solar batteries work

There are three key phases to how solar batteries capture, store and convert solar energy into usable electricity.

Energy capture and storage: When the sun’s out, solar panels transform sunlight into electricity through a process called photovoltaic (PV) conversion. Any leftover electricity that isn’t immediately consumed by your household is channelled into the solar battery for storage.

Chemical reactions: Chemical reactions in the materials housed in the battery’s cells store the electrical energy coming from your panels in the form of chemical energy, keeping it on hold until needed. Older solar batteries used lead-acid technology, which made them heavier, more difficult to maintain and with a lower ability to ‘absorb’ and output electricity. Most modern batteries use a type of lithium-ion technology that doesn’t have these downsides.

Inverter conversion: You may already know that solar panels produce a DC current of electricity and that your home requires an AC current, making it an inverter’s job to convert the DC current into AC for home use. Inverters do a similar job when a solar battery is part of the system but the interchange of AC and DC currents is more complex and depends on the type of inverter you choose.

Either way, when your household needs electricity and can’t obtain it directly from your solar panels as it’s generated, such as after dusk or on cloudy days, the stored energy in your battery gets converted back into electricity courtesy of an inverter. This converted electricity can then power appliances and lights around the home, lessening your reliance on the electricity grid.

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The benefits of solar batteries

There are three big benefits offered by adding a solar battery to your solar system.

Energy independence: Solar batteries empower their owners to be more self-sufficient when it comes to electricity by  storing surplus solar energy for use during peak demand periods or sunless stretches. Some solar batteries are even clever enough to top themselves up with electricity from the grid when electricity is at its cheapest, to make sure that if you do need to use grid energy, you’ve paid the lowest available price.

Lower electricity bills: By cutting back on grid reliance during peak times, which is when grid electricity is typically priced highest for residential users, solar batteries can help reduce your electricity bills over time. It’s important, though, to calculate what savings you may make on grid electricity and how that will balance the cost of purchasing a solar battery, so you know what your battery’s ‘payback period’ is.

Environmental impact: Using a solar system – and particularly if you add a battery to that system to maximise your household’s solar energy use – allows you to make more use of renewable energy in the form of solar power, so dialling down  your reliance on fossil fuels and lowering the carbon emissions caused by your electricity use.

Solar batteries in Australia

The current Australian climate of rising electricity costs makes a good argument for tacking a solar battery onto your solar system. But there are other reasons Australian solar set-ups are well-suited to battery use.

Maximising solar potential: With its bounty of sunshine, Australia is a solar energy hotspot. Solar batteries allow homeowners to make the most of this resource by stockpiling surplus solar electricity that they may not be able to use immediately.

Government support: There are several government incentives and rebates designed to make solar energy and battery storage systems more affordable. This is coupled with the fact that excess electricity that you don’t wish to store in a battery can be sent back to the electricity grid in return for a feed-in tariff, helping offset the cost of your battery.

Compare solar electricity plans in your state

Here are some of the cheapest solar-specific deals from the retailers on our database. These costs are based on the Ausgrid network in Sydney but prices will vary depending on your circumstances. We show one product per retailer, listed in order of lowest price first. Annual price estimates assume general energy usage of 3911kWh/year for a residential customer on a single rate tariff. Price estimates exclude solar feed-in tariff credits. These are products from referral partners†. Our database may not cover all deals in your area, and please check retailer websites for up to date information.

Here are some of the cheapest solar-specific deals from the retailers on our database. These costs are based on the Citipower network in Melbourne but prices will vary depending on your circumstances. We show one product per retailer, listed in order of lowest price first. Annual price estimates assume general energy usage of 4000kWh/year for a residential customer on a single rate tariff. Price estimates exclude solar feed-in tariff credits. These are products from referral partners†. Our database may not cover all deals in your area, and please check retailer websites for up to date information.

Here are some of the cheapest solar-specific deals from the retailers on our database. These costs are based on the Energex network in Brisbane but prices will vary depending on your circumstances. We show one product per retailer, listed in order of lowest price first. Annual price estimates assume general energy usage of 4613kWh/year for a residential customer on a single rate tariff. Price estimates exclude solar feed-in tariff credits. These are products from referral partners†. Our database may not cover all deals in your area, and please check retailer websites for up to date information.

Here are some of the cheapest solar-specific deals from the retailers on our database. These costs are based on SA Power network in Adelaide but prices will vary depending on your circumstances. We show one product per retailer, listed in order of lowest price first. Annual price estimates assume general energy usage of 4011kWh/year for a residential customer on a single rate tariff. Price estimates exclude solar feed-in tariff credits. These are products from referral partners†. Our database may not cover all deals in your area, and please check retailer websites for up to date information.

Why understand solar batteries?

Getting to know the inner workings of solar batteries is important if you want to achieve the full potential of your home solar energy system. Solar batteries take a solar system a step further away from reliance on traditional energy sources and a step closer to energy self-sufficiency.

A good understanding of how solar batteries work is also key to knowing what you’re paying for if you decide to add one to your solar system, and then keeping that battery in great working order. This article doesn’t cover the full complexity of how solar batteries function so there may be more reading you’d like to do. For a much deeper dive under the hood of solar batteries, check out this 101 guide to the devices from Solar Quotes founder Finn Peacock.

Christine Seib
Editor-in-Chief
Christine's three decades of experience as an award-winning journalist and editor, including at The Times, CNBC and The Australian, has prepared her to deliver the best digital tools and information to Australians who want to purchase products and services more easily and with greater confidence.

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