How Does Solar Battery Storage Work? A Definitive Guide

By Scott Laskey


Last Updated on January 25, 2021 by Scott Laskey
Apr 16

In recent years, residential solar battery backups have become more popular and widespread. Today, solar power generates 1.9% of all energy nationally, and battery backups have been an important part of that growth.

This is excellent news for homeowners! As households install solar batteries in higher numbers, though, there’s still confusion about the intricacies of battery systems. After all – these aren’t DIY projects, and there are many myths surrounding solar batteries.

So, how does solar battery storage work? Here’s what you need to know.

How do Solar Panels and Batteries Work?

Today, modern solar batteries (such as the Tesla Powerwall2, LG Chem, Pika Energy, and Sonnen), use lithium ion, and most are “grid-tied” systems.

While it is possible to go completely “off grid” with a battery bank for solar storage, you’d need to install numerous batteries, which becomes cost-prohibitive very quickly.  

As such, modern batteries are mostly used for back-up, supplementary power when the grid goes down, or peak shaving (using power during peak demand hours when energy costs the most).

In addition to helping you save money, solar batteries also provide predictable power while benefiting the environment.

Although most homes see their solar energy production vary according to weather patterns and solar strength, homes equipped with batteries store excess energy when they produce it, allowing the home to use it when needed.

As a general rule, during the summer months solar panels will produce 4-5 times the energy they do during the winter. This means your system will overproduce (and get credits from your utility provider) during the warmer months, and under-produce in the winter. As such, installing a solar battery can help offset some of your low winter production values.

What to do Before You Install a Solar Battery System

It’s not enough to just add batteries and be done with it. Instead, you’ve got to prepare your home to function as efficiently as possible. Here are the first steps to take:

  • Reduce your daily electricity use. This helps ensure you won’t run through your stored energy and makes your batteries more productive for your home. Look at ways to cut down your electricity use, like investing in energy-efficient appliances and taking shorter showers. You can also install a smart thermostat to help you save energy in your home.
  • Weatherize and insulate your home. Prevent needless energy loss by weatherizing your home to prevent frozen pipes and leaks and keep it warm during cool weather and cool during warm weather.
  • Research battery bank sizes. Not all battery banks are created equal. To figure out what size is right for you, you’ll want to figure out how much energy you use daily and how many “days of autonomy” (days you can draw from your bank without producing any new energy) you want built up.

The Process of Installing a Battery Storage System

To install a battery storage system on your home, you’ll need to enlist the help of a professional solar installer. This solar installer will help you do a few primary things:

1. Understand Your Daily Energy Consumption

How much energy do you use each day? How much energy does your system need to produce and save for adequate energy storage? While you can figure this out by checking in with an energy monitor, it’s also helpful to talk it over with a professional solar installer.

2. Develop a Goal for Days of Autonomy

How long do you want to be able to stay off the grid without producing additional power? While most homeowners shoot for 3-5 days of autonomy, your solar installer will help you decide what’s right for you, and what size system you need to facilitate it.

3. Research the Best Solar Batteries

Solar batteries are an exciting innovation for the solar industry, but they’re not all created equal. A good solar installer will help you research solar batteries and uncover the options that will work best for you. They’ll also be there to answer any questions you may have about the batteries in the process.

4. Install the System

Finally, the solar installer will work with you to actually install the system and hook it up to the battery backup. If you have a pre-existing solar system, they’ll be able to add batteries and wire the entire thing to work.

A Smart Choice for Eco-Conscious Homeowners

Installing a residential solar battery backup is a great way to promote energy independence and reduce your home’s carbon footprint.

If you’re looking for professional assistance or a quote for a solar battery system, get in touch with us. Our solar experts have helped many homeowners on the California Central coast integrate their solar panels with a home battery, and we’re happy to do the same for you.

About the Author

Scott is the founder of Sandbar Solar & Electric. With a Bachelor’s Degree in Economics from UC San Diego, Scott has an NABCEP certification, and has lectured on and taught many high-tech construction practices and solar PV technical concepts to education institutions, including Stanford University and state-recognized electrician apprenticeship programs. Scott enjoys sharing his knowledge of the evolving renewable energy space and making a difference in his community.

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