Solar Battery Backup for the Home: A Complete Guide for California Homeowners [2023]

Solar Battery Backup for the Home: A Complete Guide for California Homeowners [2023]

By Jeremy Pearl | The Latest Solar Energy Information

Last Updated on February 7, 2024 by Jeremy Pearl
Jul 06

Average monthly electric bills are going up. The grid in California has become increasingly unstable, and more people are looking for ways to ensure energy security – even in the event of a blackout.

Fortunately, there’s a solution to all of these problems: solar battery storage.

While solar panels can decrease your energy bills, they don’t store the excess energy you create for later use – unless you add a battery system.

Today, installing a battery backup for your home solar system can go a long way to save money and create additional energy security for you and your family.

Here’s what you need to know.

What is Solar Battery Storage?

solar battery storage

Solar battery storage is a technology that makes it possible to store excess solar energy for later use.

Today, most solar battery storage systems use lithium-ion batteries, which are efficient, lightweight, and long-lasting.

There are other common types of batteries as well, which we’ll discuss in a later section.

Overall, solar battery storage systems help increase the efficiency and reliability of solar energy systems and allow homeowners to save money and decrease reliance on non-renewable energy sources.

How Does Solar Battery Backup Work?

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Here’s how solar battery storage works when hooked up to residential PV systems:

  1. Solar panels generate electricity from sunlight during the day.
  2. The energy is converted from DC (direct current) to AC (alternating current).
  3. The AC energy powers the home.
  4. If the solar panels generate more electricity than the home uses, the battery storage system stores the excess energy rather than sending it back to the grid.
  5. The house can then pull energy from the battery storage system after the sun has set, during storms, or whenever the home’s energy needs outpace the panels’ energy production.

Some residential solar systems draw energy from the electrical grid when battery storage reserves are low. This ensures that a home always has power.

Other solar battery systems are compatible with off-grid solar systems, which are independent of the larger electrical grid.

What are the Benefits of Solar Battery Backup Systems?

Solar battery backup is an excellent option if you want to power your home with clean, environmentally-conscious, renewable energy.

In addition to providing reliable power, battery backup offers a variety of other advantages.

Here are a few top reasons to invest in backup solar batteries for your home:

1. Energy independence

Solar battery backup systems give you energy independence.

Whether you live in a place where the grid tends to be unreliable or you just want to create a more self-sufficient home, solar battery systems allow you to harness the full potential of your solar panel system both day and night and access true energy independence.

2. Maximum reliability

Installing a solar system with battery backup allows you to enjoy more reliable energy for your home.

If your home becomes disconnected from the grid, a battery backup system allows your whole home or part of your home – depending on how your backup system is configured – to run on its own microgrid during the outage.

This is an attractive benefit if you live in California, where we’ve been experiencing more severe weather events yearly, including storms and wildfires.

3. Financial savings

When you power your home with solar, you can save money on utility bills during “peak hours” when electricity prices are highest – especially as rates continue to increase yearly.

When you add solar battery backup, you’ll also enjoy grid-tie incentives, which can help make the switch to green energy more streamlined and affordable. You’ll find more information on incentives and rebates later in this blog.

4. Environmental benefits

Solar energy systems consume less energy and generate less pollution than fossil fuels.

Because of this, installing solar batteries reduces your home’s carbon footprint.

This is a considerable benefit for anyone who wants to create a greener household.

5. Less noise pollution

While generators are noisy and disruptive, solar panels and battery storage systems run (virtually) silently and won’t bother you or your neighbors.

If you already have a generator on your home, replacing it with a solar battery storage system is a great way to update your space and reduce noise pollution in the process.

6. Increased property values

In addition to making your home more efficient, a solar battery backup system also increases your property value.

According to research conducted by the National Renewable Energy Laboratory (NREL), the value of your home goes up by $20 for every $1 you save on energy bills.

That means a solar panel and battery system that saves you even $700 annually raises the value of your home by $14,000.

Not only is a home with solar battery backup more valuable, but it may also sell faster.

According to the 2021 Housing Trends Report from Zillow, 67% of homebuyers consider energy efficiency to be “very important” in a new home, and most buyers are willing to pay more for solar-powered homes.

“Whole Home” Backup Vs. “Critical Loads” Backup

whole home battery backup

It’s essential to understand the difference between backing up your whole home and backing up only essential circuits or “critical loads.”

Critical loads typically include a single refrigerator, internet equipment, a few lights & plugs, and 1 or 2 small appliances.

These system types perform differently from one another, and the cost and complexity of each option vary considerably.

Here’s a quick breakdown of each option:

Whole Home Backup

  • Batteries are interconnected directly to the main electrical system, and their electrical connection delivers power to the entire house.
  • Whole Home Backup systems cannot support larger house loads (i.e., oven, AC, hot tub, EV) unless they’re designed properly. As such, a homeowner can easily overload and fault the energy storage system when a grid outage occurs if too many devices are drawing power simultaneously.
  • Whole Home systems often require 30-60+ kWhs of backup power.
  • Whole Home Backup is more expensive than backing up only essential or “Critical Loads” and can cost $60,000+ before incentives.

“Critical Loads” Backup

  • Batteries are interconnected to a dedicated “critical loads” distribution subpanel and will only deliver power to the critical load panel in a grid outage.
  • Homeowners are responsible for load management and functional performance during a grid outage. This means that it is possible to overload the system and that the use of some circuits may need to be limited to prolong battery duration.
  • Critical Loads systems often call for 10-30 kWh of battery storage.
  • Critical Loads backup is less expensive than Whole Home backup and may cost $25,000-$50,000 before incentives.

How to Add Battery Backup to Your Existing Solar Panel System

Are you interested in installing a battery backup system for your existing solar panels?

Here’s a quick five-step guide to help you get started:

1. Assess your energy needs

Before you add battery backup, consider your home’s energy needs.

Evaluate your current solar panel system to understand if it’s generating enough energy to meet your current and future needs.

Consider adding more solar panels if you already use or anticipate using more energy than your current system produces.

If you want extra guidance, contact a solar professional like Sandbar Solar & Electric (if you live on the West Coast) to assess your current system production in relation to your current & future needs.

Sandbar Energy Consultants can also recommend a battery system that works for you.

2. Size your solar battery backup system

The size of the battery impacts how functional it will be for your home. If you’re unsure what size battery you need, ask a solar energy professional for help.

They’ll consider factors like intended use and the size of your home as they make a recommendation.

3. Consider your budget

Of course, any solar battery storage system you install needs to be within your budget.

The best way to understand the potential costs of your new battery storage system is to enlist the guidance of a solar battery installer.

If you’re worried about how to afford your system or just want to save money, look into solar battery storage incentives available in California — more on that in the next section.

4. Decide on the best battery technology for your needs

Today, there are a variety of solar batteries to choose from.

The most common options include the following:

  • Lithium-ion batteries. Lithium-ion batteries are currently the most common storage technology. They’re popular in smartphones, power tools, and electric cars, to name a few applications. The lithium-ion batteries used in solar lithium battery storage are known as prismatic batteries. While prismatic batteries are more expensive than lead-acid batteries, they feature built-in technology to prevent over-discharging and may deliver more cycles than their lead-acid counterparts.
  • Lead acid batteries. Lead acid batteries are deep-cycle batteries that have been used in off-grid solar power systems for many years. When used for energy storage, lead-acid batteries can be less expensive than their lithium-ion counterparts and may be easier to find than other battery types.
  • Flow batteries. Flow batteries are another popular solar energy storage option. Cost-effective and efficient, these cells are larger than their other types of batteries and will require additional installation space. They last longer than alternative batteries and are not toxic.
  • Nickel Cadmium. Nickel-cadmium batteries have been used since the early part of the 1900s. While they don’t provide the energy density of other solar battery storage options, they offer an extended lifecycle and are easy to manage and maintain.

If you’re unsure which battery is right for you, work with a qualified solar installer to design a system that meets your home’s storage needs and fits your budget.

5. Select the right installer

Last but not least, find the right solar battery installer for your job.

Here are a few tips to help you find and hire an experienced team:

  • Look for a certified and trained team. Your solar installer should be fully certified and should have a team of professionally trained, certified electricians and solar professionals working under them.
  • Hire a solar installer that’s transparent about subcontractors. Some solar installation companies use subcontractors to complete jobs quickly, but that can compromise the quality of the work. If you hire an installer that uses subcontractors, make sure they’re transparent about why and how they use those subcontractors and how they make sure they’re all qualified to perform the work required.
  • Work with a local company. A local solar installer will be more reliable, accessible, and knowledgeable than a large national installer. You’ll also get more personalized support and better service throughout the installation process. Finally, local installers are more likely to provide solar maintenance and can help you manage and maintain your solar system at every stage of its lifespan.
  • Consider an installer that offers financing. No matter what you do, avoid cheap solar installers at all costs. After all, you get what you pay for when it comes to solar and battery systems. If you’re worried about the cost of your solar project, consider working with an established installer who can provide financing options.

Here at Sandbar Solar & Electric, we know finding a reliable solar contractor can be intimidating, so our team is here to answer any questions you may have. Contact us today to learn more. We provide a no-pressure, advisory type of consultation to help you find the best solution that fits your needs and budget.

What Solar Battery Storage Incentives Are Available in California?

home solar battery backup california

Are you looking for ways to save money on your solar battery backup system?

If you live in California, you may qualify for the following solar battery storage incentive programs:

The Self-Generation Incentive Program (SGIP)

  • SGIP is California’s top storage incentive program. It provides California homeowners and businesses with an upfront rebate for adding energy storage systems.
  • This is a tiered-block program, which means that the values of the incentives decline over time as the state approves more battery installations.
  • The value of the rebate you could receive under this program depends on the size of the battery system you install.
  • For most residential customers, that is about $150 per kWh of energy storage capacity.

The Federal Investment Tax Credit

  • This adds up to a tax credit of about $10,000-$15,000 for most homeowners.
  • Standalone battery storage recently became eligible for this program thanks to the Inflation Reduction Act.

Equity Resilience Incentives

  • Under the SGIP program, California provides an additional incentive for programs under the “Equity Resilience” umbrella.
  • “Equity Resilience” projects usually include low-income households and people who live in places designated as high-risk fire areas, including those who have experienced Public Safety Power Shutoffs (PSPS) events twice or more.
  • Customers who meet the criteria for these incentives are eligible for SGIP rebates of $850-$1,000 per kWh.

The Limitations of Battery Storage Systems

While your energy storage system can deliver power in a grid outage situation, it is essential to recognize battery storage systems do have limitations in performance and should not be relied upon for the following:

  • Life safety or medical systems
  • Security systems, or
  • Maintaining environmental controls or protection for valuable assets


Can a solar battery backup system power my entire home?

In some cases, yes.

It usually takes about 3-6 battery backup modules to power an entire home. New standards for energy storage controllers are making battery backup systems more powerful and capable of generating more power output capacity.

How long will the batteries last?

The lifespan of a solar battery backup system varies depending on a few factors, including the brand and type of battery, its capacity, and its charge level.

When properly installed at your home or business, a battery backup system will generally operate for 10-15 years before needing replacement. For specific battery lifespan questions, reach out to your solar installer directly.

Can I add a battery backup to an existing solar panel system?

Yes, it is possible to add battery backup to most existing solar panel systems. Contact your solar battery installer to check the compatibility of your current solar equipment and your preferred battery.

How much does a solar battery backup system cost?

It depends.

The cost of a solar battery backup system varies depending on the manufacturer of the products you use, the type of batteries you’re installing, your system’s power capacity, additional electrical work needed to configure your backup load panel (if any), as well as the installation fees you pay and other factors.

In Central California, it’s common to pay between $1,400 and $2,000 per kWh of battery storage (for a fully installed system). For example, installing 13.5 kWh of battery storage may cost approximately $18,900 after the 30% federal tax credit is factored in.

Speak with your solar installer for a more specific price estimate.

If there’s an upcoming storm, can I charge my battery backup in the event of a blackout?

With certain battery types, before a storm arrives, you can adjust the settings on your battery backup to “backup mode,” which allows you to charge your batteries completely. Many current batteries have a “storm watch” mode that automatically uses the grid to charge batteries fully if a storm is approaching.

How long can I power my home with battery backup when the power goes out?

It depends.

The ability of your battery backup system to power your home depends on your current household load, the amount of storage you have, and how capable your battery backup system is to power this load.

It also depends on how freely or conservatively you use the backup power. Limiting your battery use will extend the duration of your backup power.

Considering Installing Battery Backup on the Central Coast? Turn to Sandbar!

If you’re interested in installing battery storage backup in the Central Coast area, Sandbar Solar & Electric is here for you.

Sandbar Solar & Electric installs Tesla Powerwalls, Enphase batteries, and SimpliPhi, as well as a variety of other products.

To learn more about solar batteries, contact Sandbar Solar today.

Sandbar Solar & Electric is an established, locally-owned solar company that’s been in business for over 19 years.

We specialize in helping our customers choose the correct solar batteries for their homes and budgets. We do everything we can to help our customers get educated and choose the right solar battery systems.

Our services include free estimates, custom design, and expert installation. We’re proud of our reputation for designing and installing the most efficient solar panels for the Central Coast – including Santa Cruz and Monterey counties – as well as San Jose, Los Gatos, Morgan Hill, and many other parts of the Bay Area.

About the Author

Jeremy has worked in the solar industry since 2006. He has a Bachelor’s Degree from UC Santa Cruz in Environmental Studies. Jeremy has spent most of his solar career in residential sales and Sales Management in both California and Hawaii. He was raised in Santa Cruz County and is passionate about helping local residents make the switch to clean and reliable renewable energy. Jeremy lives on the Westside with his wife and two boys and enjoys music, photography and hiking in his personal time.