Do you need a battery with your solar system?

What a battery actually does

Solar panels only make power while the sun's up. Without a battery, anything you don't use during the day goes back to the grid, and you buy power back at night. A battery stores that spare daytime energy so you can use it in the evening instead.

Feed-in tariffs, the amount you're paid for power you send to the grid, have dropped a lot over the years. That's made storing and using your own solar far more valuable than exporting it.

Signs a battery could be worth it

• You use a lot of power in the evening. If the house is empty during the day and busy from 5pm, a battery lets you run on your own solar through the most expensive part of the day.
• You're exporting a lot of solar. If your system regularly sends most of its output to the grid for a few cents, that energy is better off stored.
• You get regular blackouts. On rural properties, outages can mean no water pumps, no fridges and no power for stock or equipment. A battery with backup capability can keep the essentials running.
• You're on a time-of-use plan. Batteries help you avoid peak rates.
• You're planning an electric vehicle or more electric appliances. A battery gives you room to grow.

When a battery might not stack up yet

• You're home and using power during the day. If you already use most of your solar as it's made, a battery has less spare energy to store.
• Your solar system is small. A battery needs surplus solar to charge from. Sometimes adding panels first is the better move.
• Your power use is low overall. Smaller bills mean a longer payback period.

Not all batteries provide backup

This catches a lot of people out. Some battery systems keep running during a blackout and some don't, unless they're set up with the right hardware. If backup power is important to you, make sure it's part of the design from the start.

What about the cost?

Battery prices have come down, and the federal Cheaper Home Batteries Program takes a solid chunk off the upfront cost. In NSW you may also be eligible for an incentive for joining a virtual power plant. We cover both in our article on solar rebates and incentives in NSW.

Sizing matters more than brand

Bigger isn't always better. A battery that's too large won't fill up on most days, and one that's too small won't get you through the evening. The right size depends on your actual usage, which is why we look at your power bills and how you use energy before recommending anything.

Can you add one later?

Yes. If you already have solar, a battery can usually be added down the track, though it depends on your existing inverter. If you're installing solar now and think you'll want a battery later, let us know so we can plan for it.