December 06, 2023

Home battery backup 101


Summary: Home battery backup provides peace of mind if there are any grid outages and helps balance out the amount of solar that your rooftop generates. They are great if you live in areas that have constant power outages or you want to save even more money on your energy bills.

Home batteries are energy storage systems designed to hold excess electricity for later use. They work in tandem with your home’s energy sources—be it from the grid or solar panels on your roof—to store surplus energy when demand is low. This stored energy can then be used when you need it most, such as during peak hours or power outages.

The Technology Behind Home Batteries

Home batteries are typically made of lithium-ion cells, the same technology that powers your smartphone and electric vehicles. These cells are known for their high energy density and long cycle life, making them ideal for home storage solutions. The battery management system (BMS) is another crucial component. It monitors the battery’s performance, ensures safe charging and discharging, and optimizes the battery’s lifespan.

It’s worth noting that the future of home batteries isn’t limited to standalone units. Bidirectional electric vehicles like the Ford F150 Lightning are emerging as viable backup batteries for homes. These vehicles can both draw energy from and supply energy back to the home, offering an additional layer of resilience and flexibility.

There are many different home battery manufacturers. At Daylight, we prefer the Franklin Home Power system from FranklinWH.

Where does a home battery get its energy?

A home battery system must be charged by an energy source. Just like the battery in your phone, it cannot generate it’s own power – it must collect it from somewhere else. There are two sources of power for your battery:

Solar panels

The majority of home batteries are powered by rooftop solar panels. The solar panels produce energy during the day as the sun is shining, and the excess energy that your home is not using charges up your battery. This allows you to use that solar energy at a later time when the solar system isn’t producing, like at night. Additionally, pairing a battery with solar ensures you always have access to reliable electricity, even if the grid is down.

The grid

However, you don’t have to pair a battery with solar panels. You can also charge a battery directly from the grid. The battery will draw energy from the grid to be used at an optimal time, either when energy is expensive or there is a power outage.

Why are home batteries important?

Energy independence

One of the most compelling reasons to invest in a home battery is the independence it offers. With a reliable storage system, you’re less dependent on the grid, giving you greater control over your energy consumption and costs. This is particularly beneficial during peak hours when electricity rates are at their highest.

Resilience during outages

Natural disasters and grid failures are unfortunate realities. A home battery can serve as a backup power source, keeping essential appliances running and providing peace of mind during emergencies.

Better solar utilization

If you’ve already made the transition to solar energy, a home battery can take your setup to the next level. Instead of sending excess solar energy back to the grid, you can store it for personal use, maximizing your investment in solar technology.

Long lifetime

A typical home battery can last between 10 to 15 years, depending on usage and other factors like temperature and maintenance. The cycle life of a home battery refers to the number of complete charge and discharge cycles it can undergo before its capacity significantly diminishes. Most modern home batteries offer around 5,000 to 10,000 cycles, making them a long-lasting investment.

Do you need a home battery backup system?

While home backup batteries are useful, they may not be necessary for your home. To determine if you need a battery, ask yourself the following questions:

Do you experience frequent power outages?

If you find yourself grappling with frequent and extended power outages, a solar-plus-storage system could be a game-changer for you. While solar panels alone can’t power your home during an outage due to safety concerns for utility workers, a solar-plus-storage system with islanding capabilities can. This means your system is equipped to automatically disconnect from the grid during a power outage, allowing you to run your home independently. 

Does your utility have a net metering program?

For those with solar panel systems, net metering can be a significant factor in your decision to invest in a home battery. When your solar panels produce more electricity than you need, you can earn credits from your utility for the excess energy sent back to the grid. These credits can offset your energy costs when your panels aren’t generating enough electricity. If your utility offers a robust net metering program, a battery might not add much value. However, if your utility’s net metering policy is less favorable, a home battery could be a worthwhile investment.

Does your utility offer time of use rates?

Even if you haven’t made the leap to solar, a home battery can still be a wise investment, especially if your utility employs a complex rate structure like Time-of-Use (TOU) rates. These rates fluctuate based on supply and demand, varying from hour to hour and season to season. A home battery allows you to store energy when it’s cheap and use it when rates are high, optimizing your energy costs.

Incentives to consider

There are significant federal and local incentive programs that can help offset the cost of a home battery. These programs can make the investment more financially feasible.

Federal investment tax credit

One of the most compelling incentives for home batteries is the Federal Investment Tax Credit (ITC). Unlike a tax deduction, which merely reduces your taxable income, the ITC allows you to apply 30% of your battery system’s upfront cost directly toward your federal tax bill. If you’ve overpaid your taxes during the year, you could receive this credit as a refund. Any excess credit can also be rolled over to the following year.

Bring your own battery programs

Programs like “Bring Your Own Battery” (BYOB) offer another financial incentive. In these programs, you grant your utility access to your battery’s stored energy during high-demand periods. You’re then compensated on a dollar-per-kilowatt basis for the energy your utility draws from your battery. For instance, in Massachusetts, the ConnectedSolutions program pays about $275 per kW per event, which could result in annual earnings of around $1,375 for a typical home battery.

Virtual power plants

Your solar-plus-storage system acts as a mini power plant. When aggregated with other similar systems, they form a Virtual Power Plant (VPP). Participating in a VPP allows you to earn money either by letting your utility access your stored energy during high-demand periods or by using your stored energy instead of drawing from the grid. Payment structures for VPPs can vary, ranging from one-time participation payments to ongoing payments based on the amount of energy you contribute.


Home batteries represent a significant advancement in personalized, efficient energy solutions. They offer a range of benefits, from energy independence to financial savings, making them an increasingly popular choice among homeowners committed to sustainable living. As we continue to seek ways to minimize our environmental impact, the role of home batteries will undoubtedly become more central, powering our homes more efficiently and sustainably than ever before.

If you’re interested in learning more about whether home battery backup is right for you, we’re here to help. Feel free to reach out to our team to ask questions and talk through our process.


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