As more homeowners explore the benefits of solar energy and battery storage, we often hear questions about system flexibility, grid independence, and battery expansion. In this blog, we’re answering some of the most common questions we receive about solar batteries, like the Tesla Powerwall and Franklin aPower2, and how they fit into your home energy strategy. 

Can I Add a Second Battery Unit in the Future? 

Yes! Today’s battery storage systems are modular, meaning you can start with one unit and add more later as your energy needs grow. Whether your household’s electricity usage increases over time, or you want to expand your backup power capacity, adding an additional battery is a straightforward process. 

What Happens to a Grid-Tied Solar Battery Storage System When the Grid is Down? 

When the power grid goes down, a grid-tied solar system with battery storage automatically switches to island mode, meaning your home runs off stored solar energy instead of drawing from the grid. This transition happens seamlessly with the help of your inverter and battery system, ensuring you have backup power when you need it most. 

Here’s what technically happens when the grid goes down: 

1. Solar Panels – If the sun is shining, your solar panels will continue to generate electricity. However, instead of sending excess energy back to the grid, this energy is directed to charge the battery and power essential home loads. 
2. Inverter – The inverter plays a critical role in detecting grid outages. When the grid goes down, the inverter disconnects from the utility grid to prevent power from being sent back onto the grid—a safety requirement known as anti-islanding protection. The inverter then shifts to off-grid mode, converting the DC electricity from your battery into AC power for your home. 
3. Battery System – Your battery takes over as the primary power source, discharging stored energy to keep essential circuits running. If the battery is connected to solar, it will recharge during daylight hours, extending backup power for as long as possible. Both the Tesla and Franklin battery offering allow you to prioritize certain loads in real time on your app, like refrigerators, medical devices, or well pumps, to make the most of your stored energy. (click here for a grid outage demo featuring the Tesla App) 

How is This Different from When the Grid is Online? 

Under normal conditions, a grid-tied solar system operates as follows: 

• Solar panels generate electricity, which is first used to power your home. 

• Excess energy is either stored in the battery or sent back to the grid for credits (net metering). 

• Your home still draws power from the grid when solar production is low or at night. 

When the grid is down, your system must island itself to prevent unsafe electricity flow back onto power lines. Instead of feeding power to the grid, your system prioritizes using solar energy for your home and battery to keep essential loads running. 

This setup ensures energy security and self-sufficiency, especially during unexpected outages. Want to learn more about how battery storage can enhance your solar system? Contact us today! ☀️🔋 

Can I Install Fewer Solar Panels to Only Charge a Battery Unit for EV Charging? 

Technically, solar panels can be installed just to charge a battery, but it’s not an economical solution for residential customers. The size of the battery system must be carefully matched with the solar array and the energy loads it will support. At Kokosing Solar, we design solar and battery storage systems to optimize energy efficiency and savings, rather than as standalone EV charging stations. 

Can I Install Fewer Solar Panels to Only Charge a Battery Unit for Backup Power? 

Similar to the EV charging question, installing a solar and battery system solely for backup power in case of a grid outage is not the most cost-effective approach. Your battery capacity, solar array size, and backup power needs should all be carefully balanced to maximize your investment and energy independence. Our team ensures that every system we design provides practical, long-term value for your home. 

The Bottom Line 

Solar and battery storage solutions offer energy security, cost savings, and flexibility, but they work best when designed as part of a comprehensive system. If you’re considering adding a battery backup to your home solar setup, our team is here to help you find the best solution for your energy needs. 

Have more questions? Fill out the form below to learn more about solar + battery storage! ☀️🔋