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Do You Need Batteries For Solar Panels?

Energy storage systems, like backup batteries for solar panels, provide a way to live independently and be ready for power outages. They give you control over your electricity and make you feel secure. This new technology allows you to be self-sufficient and prepared for any disruptions in the power supply.

With a solar battery storage system, you can have peace of mind knowing that you have a reliable source of power. These systems allow you to store excess energy from your solar panels. You can use this stored energy during power outages or high-demand periods. This ensures that you always have power when you need it. 

Using solar power reduces reliance on the grid and helps manage energy use better, potentially lowering electricity bills. Moreover, installing solar panel systems can enhance the worth of your residence and promote a lifestyle that is more environmentally friendly and sustainable.

Why do you need batteries for solar panels?

batteries for solar panels

Here are 3 Reasons to add Batteries for solar panels


Solar power systems usually turn off during power outages, which can leave homes and businesses vulnerable. Protect your operations with a battery backup system. This makes you independent from the unreliable grid and resilient to power outages.

Batteries typically can be installed independently of a solar system for emergency use. Solar panels can recharge these batteries even when the grid is down, ensuring continuous power supply.


Take control of your electricity costs and reduce your bills by managing your energy consumption. Use your battery to use the energy stored from your solar system during the day after the sun sets. This strategy is beneficial for both homes and businesses, helping you avoid high electricity rates during peak hours. Businesses can also save money by avoiding extra charges from the utility company.


Utility bills have been increasing over the years, including charges for generating and distributing electricity. You can save money on utility bills by adding a battery and using solar power when needed. This will help you rely less on the grid. Adding a battery and using solar power can reduce your dependence on the electricity grid.

This will also help you save money on your utility bills. Solar customers can save more money as utility rates increase because they don’t have to pay the higher costs.

Best Batteries for Solar Panels

The four main types of solar batteries are lead-acid, lithium-ion, nickel-cadmium, and flow batteries. Here’s a brief overview and definition and lifespan of solar batteries:

Lead-acid Batteries

Lead-acid batteries are one of the oldest and most widely used types of rechargeable batteries. They consist of lead plates immersed in sulfuric acid. These batteries are relatively inexpensive and reliable. However, they have a shorter lifespan, lower energy density, and require regular maintenance.

Sealed Lead-Acid (SLA) Batteries

Sealed lead-acid batteries, also known as valve-regulated lead-acid (VRLA) batteries, are a type of battery. SLA batteries do not need regular maintenance like flooded lead-acid batteries. They do not require checking and refilling water levels. Seal them to prevent leakage and generally recombine gasses internally, reducing the need for venting.

SLA batteries come in two main types: gel cells and absorbed glass mat (AGM). Gel cells use a gel substance to hold the electrolyte. AGM batteries use a fiberglass mat to soak up the electrolyte.

Both types provide reliable power, are resistant to spillage, and can operate in various positions. People commonly use SLA batteries in situations that require safety, reliability, and low maintenance. These situations include emergency lighting, UPS systems, and mobility devices.

Lithium-ion Batteries for Solar Panels


Lithium-ion batteries use lithium ions to store and release energy. People commonly use them in a wide range of applications, from smartphones to electric vehicles. Lithium-ion batteries have a high energy density, long periods, and require minimal maintenance. On the downside, they are more expensive than lead-acid batteries and can be sensitive to high temperatures.

Nickel-cadmium (NiCd) Solar Panel Batteries

Nickel-cadmium (NiCd) batteries use nickel oxide hydroxide and metallic cadmium as electrodes. They are durable, can operate in a wide range of temperatures, and have a long cycle life. However, they have a memory effect where they lose capacity if not fully discharged before recharging. They also contain toxic metals, which makes them harmful to the environment.

Flow Batteries

Flow batteries store energy in liquid electrolytes contained in external tanks. The cell stack pumps electrolytes to produce electricity. These solar batteries have a long lifespan. They can easily be expanded for more energy storage.

You can also leave them unused for extended periods without causing damage. However, they have lower energy density than lithium-ion batteries and are more difficult and expensive to install.

Deep Cycle Batteries for Solar Panels

Deep cycle batteries are rechargeable batteries designed to regularly discharge most of their capacity. Starter batteries provide a quick burst of energy to start engines. Deep cycle batteries offer a steady amount of power over a longer period.

People commonly use these batteries in applications such as solar energy systems, marine equipment, and golf carts. These batteries are designed to handle being drained and recharged often, making them perfect for situations where that is necessary.

Deep cycle batteries have thicker plates than regular batteries. This helps them provide consistent power and last through more charge and discharge cycles. Different types of batteries like lead-acid, lithium-ion, and nickel-cadmium each have their own pros and cons.

Deep cycle batteries are important for applications needing consistent power and the ability to handle frequent and deep discharges.

Depth of Discharge (DoD)

Depth of Discharge (DoD) measures the percentage of a battery’s capacity that has been used. A 100% DoD indicates that the battery has fully discharged, while a 0% DoD indicates that it has fully charged. Properly managing DoD is crucial for battery health and longevity.

Do not discharge lead-acid batteries below 50-80%, while lithium-ion batteries can handle up to 80-90% discharge. Following recommended DoD levels helps maintain battery efficiency and extend its lifespan.

How Do Batteries Work?

Battery Bank:

The battery bank stores electricity generated by your solar panels, similar to how a phone battery stores power. You can use this stored energy later, such as during the night or power outages. Over time, batteries degrade and hold less charge, making a good warranty crucial.


An inverter-charger converts the direct current (DC) from solar panels into alternating current (AC) for home use. The charge controller manages how the battery charges and uses power in your solar system. The main hub for distributing power.

Backup Subpanel:

A backup subpanel connects essential devices (like refrigerators) in a separate electrical panel. During a power outage, this sub panel keeps important devices powered by the battery, separate from the main grid.

System Controller:

The system controller, or smart switch, detects power outages and disconnects your home from the grid. This keeps important devices running with a small, internal “micro-grid” that works separately from the main power grid.


The meter tracks the energy you send to and pull from the grid. With Net Energy Metering (NEM), you earn credits for excess electricity produced by your solar panels. You can use these credits to offset the cost of electricity drawn from the grid when your solar production is low.


Most battery systems connect to the main power grid, making them grid-tied. This connection allows you to use electricity when needed and send extra electricity back to the grid, saving money. Batteries help you avoid peak hour charges by using stored power during high-demand times.

Solar panels generate electricity in the form of direct current (DC). The solar panels send this electricity to the inverter-charger.

During the day, any extra power can charge your battery. The inverter-charger converts power to AC, which then powers your appliances through the main electric panel and backup subpanel.

If your battery is fully charged, you can send extra electricity back to the grid. Net Energy Metering (NEM) accomplishes this. By doing this, you can receive credits from your utility. During overcast days, you may have to rely on the power grid to charge your battery or supply electricity to your house.

At night when solar panels aren’t working, you can use your battery for electricity. The inverter-charger changes the electricity and sends it to both electrical panels.

You can also use the grid at night. You’ll use the credits you got from the utility during the day. This works best for batteries used only for emergencies.

Batteries let you use solar power for necessary things when there’s no electricity.

You can use solar power for your backup stuff, and more power will charge your battery. You will connect your refrigerator, internet router, and specific lights to a backup subpanel. This will prevent overloading your main panel. Your emergency system will operate independently of the grid during a power outage.

How Battery Backup Systems Works During Normal Day, Night and Power Outage

During power outages, there is an automatic shutdown to protect utility workers from unexpected electricity in the grid. This means your solar system won’t work in a power outage if you don’t have a battery and backup subpanel.

At night, your battery can power essential items in the backup subpanel when the solar panels are not generating electricity.

Grid-Tied Battery Systems

During the day, your solar panels generate electricity. Your solar panels generate electricity during the day.

You can use this energy immediately or store it in a battery for later use. This is helpful when you’re not home and don’t need the power right away. Your battery stores energy for when solar panels can’t produce enough electricity and your power needs increase.

If your appliances don’t need power and your battery is full, you can send extra electricity back to the grid. This can earn you credits through Net Energy Metering (NEM) from your utility company.

Use the electricity stored in your battery at night. Charge the battery during the day with extra solar power. This way, you can still have power when your solar panels are not working. If your battery doesn’t have enough stored energy, you can also get electricity from the grid at night. In that case, you’ll use credits collected during the day in exchange for the extra solar energy you sent to the grid.

A grid-tied battery doesn’t work as a backup and won’t keep your home running in a power outage. If you don’t have an intelligent switch that detects a power failure and isolates the solar and battery system from the grid, and if there’s no backup subpanel to segregate crucial devices, the battery by itself is incapable of powering your household appliances.

Needing fewer tools means a cheaper way to store power. A grid-tied battery system costs approximately 35% less than a backup battery system.

Cost of Batteries for Solar Panel Systems in California in 2024

The price of solar battery storage systems in California in 2024 varies based on different factors. However, as technology improves and more people start using these systems, experts expect the cost to decrease over time. In 2024, experts expect a solar battery in California to cost between $5,000 and $20,000, including installation.

Important to note that these costs are approximate and can vary depending on your specific installation needs. Factors such as the battery’s capacity, brand, quality, and installation complexity all affect the final cost. Incentives and rebates can lower the cost of solar battery storage systems, making them more affordable for homeowners.

Battery Fast Facts

Your solar PV system will not operate during a power outage unless you have a battery.

The 30% tax credit for solar also applies to energy storage if the solar panels charge the battery. We’ll supply you with all the necessary details to optimize the tax advantages of your solar setup.

The Self Generation Incentive Program compensates users for a portion of their battery expenses. Don’t worry about the paperwork, we’ll take care of all incentives and rebates for you!

Most batteries now use lithium-ion, but some are made with safer and more eco-friendly chemicals. Solar Earth is committed to using cobalt-free batteries. They will provide you with information about the specific batteries they use.

The warranty of a battery significantly affects the viability of your investment. Ensure to have a thorough conversation about this with your installation expert.

Solar and energy storage are long-term investments where quality and safety are more important than quantity and discounts. If you have questions, we can help you choose the best energy storage system for your needs. Just ask us for the information you need.

Solar batteries can store a limited amount of energy, which varies depending on their type and model. On other hand, traditional generators can supply power to your household for anywhere from a few hours to several weeks, depending on the availability of fuel.

Final Words!

Backup batteries for solar panels for storing solar energy have become increasingly popular recently, leading to widespread but sometimes misleading or confusing information. We have provided some basic breakdown of batteries so you can make the right choice for your system. 

At Solar Earth Inc., our engineers and designers install residential and commercail storage solutions for managing extra solar energy. They also keep up with the latest storage technologies. Contact us for complete residential and commercial solar installations with battery backup systems.