Can You Add a Battery to an Existing Solar System & Is It Worth It?
When you first went solar, adding a battery might not have made sense. Costs were high, and net metering made it easy to send power back to the grid. But things have changed.
Battery storage has become more affordable and more valuable, especially as net metering incentives shrink, electricity prices keep climbing, and the grid becomes less reliable due to extreme weather and high demand.
If you’re ready to add a battery to your solar system now, keep reading. It’s possible and, in a lot of cases, fairly simple. But the cost and complexity can vary quite a bit depending on how your system was originally designed.
How Retrofitting a Solar Battery Works
How easy it is to add a battery to your solar panels depends primarily on what type of inverter you have.
If You Have a Hybrid Inverter
If your solar system already has a hybrid inverter, it’s typically much easier and cheaper to add a battery.
A hybrid inverter is a special type of inverter that can handle both your solar panels and a battery system.
To understand why this matters, it helps to know a bit about how solar power works. Solar panels produce DC (direct current) electricity, but your home runs on AC (alternating current) power. Inverters are what convert DC to AC so you can use the electricity your panels generate.
Standard inverters can only convert solar energy from DC to AC. But a hybrid inverter does more. It also controls battery charging (which uses DC) and discharging, and can decide where to send power, whether to your home, your battery, or back to the grid.
If You Don’t Have a Hybrid Inverter
If you don’t have a hybrid inverter, it’s a little trickier to add battery backup to your home solar panels. But it’s still possible in most cases.
Your two main options are to either replace your inverter or install an AC-coupled battery.
Replace Your Inverter for Battery Retrofit
The first option is to replace your current inverter with a hybrid inverter. This allows you to install a standard, DC-coupled battery.
The main benefit of installing a DC-coupled battery is better efficiency and battery performance. But this approach is also more expensive. We may need to make design changes to your system, in addition to replacing the inverter itself, which can add to the cost.
Install an AC-Coupled Battery
The other option is to add an AC-coupled battery, which works alongside your existing inverter. This setup uses a second inverter that converts AC power from your solar system into DC to charge the battery, and then back into AC when discharging to your home.
Although the energy goes through more conversions, manufacturers have been able to make the process very efficient. It’s often the simpler and more affordable way to retrofit a battery without replacing your current inverter.
What About Adding More Batteries to an Existing System?
If you already have a solar plus storage system, adding another battery to your solar panels is easy. Most battery systems are modular, which allows you to stack multiple batteries together. These systems are designed to grow with you.
There are limits to the number of batteries you can stack together, and these limits vary by make and model. But for most homes, the limits far exceed the amount of storage you would ever realistically need.
Is Adding Battery Storage to Your Solar Panels Worth It?
Installing a solar battery is expensive, especially if you’re adding one to an existing system that needs to be reconfigured. But for many homeowners, solar batteries are worth the cost.
- Backup Power During Outages – A battery gives you peace of mind during blackouts. You’ll be able to keep essentials like lights, refrigerators, and medical devices running, even when the grid goes down.
- Bigger Electric Bill Savings – With a battery, you can store extra solar energy and use it during peak demand periods, when utility rates are higher, bringing your bills down.
- Incentives Can Help Cover the Cost (For Now) – Battery installations qualify for the 30% federal solar tax credit, making the investment much more affordable. But new legislation threatens to eliminate the credit at the end of 2025. If you’ve been thinking about installing a battery, now is the best time.
Whether you’re not sure if a battery makes sense for your home or you’re ready to install one, SouthFace Solar & Electric can help.
We’ve retrofitted batteries for all types of solar energy systems in Arizona, including ones we did not originally install. Our team can assess your system, walk you through your battery options, and help you take advantage of tax credits to reduce your installation costs.
