Solar batteries: What you should know

Solar energy produces minimal greenhouse gas emissions and can help you reduce your dependency on fossil fuels. What’s more, you can make the most of this power source even when the sun isn’t shining by installing solar batteries to capture and store the energy from your solar panels for when you need it.

Having enough solar storage to meet your household’s electricity needs is critical, but how do you know which type of battery is right for you?

What is solar battery storage?

Solar energy storage systems work on the same principle as other batteries. Essentially, they give you an easy way to stockpile electricity, which you can use later as required. This gives you a reliable cache of solar-generated power to fall back on during the night or on dark and cloudy days.

There are a few different types of battery energy storage that may be appropriate for your solar system, depending on your budget and energy needs:

• Lead-acid batteries. One of the older and more common types of solar batteries, lead-acid batteries are cheaper than most on the market. However, they are also slow to charge, require regular maintenance and don’t last as long as other batteries.
• Lithium-ion batteries. In recent years, lithium-ion batteries have begun to overtake lead-acid batteries due to their longer lifespan and greater storage capacity in comparison to their size. While more expensive than lead-acid batteries, they’ve dropped in price in recent years.
• Liquid ‘flow’ batteries. Flow and flywheel batteries use liquids to store energy. They’re easily maintained and the longest-lasting type of solar battery, but they’re the most expensive and don’t generally store as much energy as lithium-ion batteries.¹

How do solar batteries work?

Most home solar battery systems need an inverter that turns the raw power generated from the solar panels (a direct current [DC]) into electricity that can be used by your home (alternating current [AC]). The inverter then directs any unused solar energy into your batteries during the day.²

When the sun goes down and the solar panels stop producing power, your inverter will ‘turn around’ and energy can be drawn from your solar batteries to power your appliances as you need it. Inverters typically only need to be replaced every 10 to 15 years.³

Apart from your solar batteries and panels, you’ll likely still require a connection to the local energy grid so you can draw on electricity from it in case you run out of solar power from your batteries. Depending on your solar system and batteries, you might be able to adjust your settings in real time to control a few things. For example, you might want to change:

• Where the generated solar energy is sent (either to your home battery storage or to the local grid ).
• Solar energy usage from your batteries during the day – it can be useful to set a cap on your daytime solar energy usage to ensure you have enough to last through the night.

As for charging your solar batteries, they typically charge automatically based on how much sunshine the solar panels receive and the power they generate. Using your inverter, you can potentially charge the battery system faster by only using power from the local energy grid (if your home is connected).

Once your batteries are fully charged and can’t store any more solar power, you are able to send power to the grid. Your inverter will flip to sending additional power to the local grid until you adjust the settings and draw on your own battery power. Otherwise, this excess power could be ‘lost’.

What are the benefits of investing in a battery storage system?

By storing solar energy, your battery allows you to harness even more solar power from the sun through your solar PV system. This means you need less electricity from the energy grid, which can help you reduce your energy bills.

If your solar battery inverter is off-grid, you can potentially use the backup power stored in your battery during a blackout or other power outage.

Another benefit for homeowners and businesses is that they can receive credits by sending excess solar power back to the grid. Solar feed-in tariffs are the rate credited to you by your retailer for the electricity you generate from your solar panels and feed to the grid.

In conjunction with a feed-in tariff, solar batteries can help offset the cost of your household’s energy bills.

Solar energy is also a growing source of renewable energy that helps reduce Australia’s carbon footprint. Solar energy is a form of clean energy that allows us to move away from those sources that release large amount of greenhouse gas emissions, such as fossil fuels.

You can explore other renewable energy options here.