Solar panels make power during the day, but most homes use the bulk of their power at night. A battery bridges that gap by storing your daytime solar so you can run the house after dark, instead of exporting cheap and buying back expensive. And yes, you can almost always add one to the panels you already have.
How a battery connects to your solar
There are two common ways to add a battery to an existing solar system:
- Hybrid inverter. Your installer replaces your solar inverter with one that runs both solar and battery. Efficient and tidy, but it means changing the inverter.
- AC-coupled battery. The battery brings its own inverter and sits alongside your existing solar inverter. Simpler to retrofit, and what many homes with newer solar choose.
Some batteries make this even easier by building the inverter in. Your installer picks the approach that suits your current setup and goals.
What you need to add a battery
- Existing rooftop solar (or solar going on at the same time).
- A compatible hybrid inverter, or room for an AC-coupled battery.
- Space on a wall, usually the garage or the side of the house.
- An accredited installer to meet the standards and claim your rebates.
Cost and rebates
Adding a battery to existing solar costs roughly $7,000 to $10,000 installed for a typical 10kWh unit after the federal Cheaper Home Batteries discount, with your state incentive stacking on top. Want your number now? Try the savings calculator.
Do you even need a battery?
A battery is worth it for most solar homes with high evening use and a low feed-in tariff, but not for everyone. We lay out the full case in are solar batteries worth it?