Do You Need Solar Battery Backup and Is It Worth It?

Home energy storage · Feb 12, 2024

As the grid situation continues to become more unstable, causing inconveniences to daily lives on an expanding scale, more homeowners are choosing to add solar energy production to create a certain level of energy independence.

Solar panels alone, however, can’t provide the needed independence on cloudy days or at night. Solar battery backup is a way to store solar energy and use it when sunshine is not available.

In this article, we will provide an introduction to solar batteries and whether they're worth your money.

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What Are Solar Batteries and How Do They Work?

Solar batteries, also known as home batteries or residential batteries, are used to store energy generated by solar panels and then provide energy when solar production is not sufficient or during power outages.

A home energy management system connects the solar panels and the batteries. While solar charging is the most common scenario, such a system can store power from a variety of energy sources, including the grid, generators, wind, and more.

Read Home Energy Management with Storage: Empowering Efficiency and Sustainability to learn more.

Types of Solar Batteries

There are three major battery types.

Lead-Acid Batteries

Lead-acid batteries use a chemical reaction between lead plates and sulfuric acid to store and release energy. They are among the oldest rechargeable battery technologies.

Efficiency: Moderate efficiency, typically ranging from 70% to 90%.

Lifespan: Typically around 3-5 years but can last longer with proper maintenance.

Cost-effectiveness: Relatively low initial cost compared to other battery types.

Pros: Low initial cost, widely available, can handle high current loads.

Cons: Heavy and bulky, requires regular maintenance (water topping), limited cycle life, relatively low energy density, not environmentally friendly due to lead and sulfuric acid content.

Lithium-Ion Batteries

Lithium-ion batteries use lithium ions to move between the anode and cathode to store and release energy. They are lightweight and have high energy density.

Lithium iron phosphate (LFP) is a sub-category of lithium-ion and is by far the safest battery chemistry for home batteries.

Efficiency: High efficiency, typically over 90%.

Lifespan: Generally 5-15 years, depending on usage patterns and quality.

Cost-effectiveness: Higher initial cost compared to lead-acid but can be more cost-effective over the long term due to higher efficiency and longer lifespan.

Pros: High energy density, lightweight, low maintenance, longer lifespan, suitable for various applications.

Cons: Higher initial cost, potential for thermal runaway and safety concerns if not properly managed, environmental impact of lithium extraction and disposal.

Nickel-Cadmium (NiCd) Batteries

Nickel-cadmium batteries use nickel oxide hydroxide and metallic cadmium as electrodes and an alkaline electrolyte to store and release energy.

Efficiency: Moderate efficiency, typically around 70-80%.

Lifespan: Generally around 5-10 years, with proper maintenance.

Cost-effectiveness: Moderate initial cost, but less cost-effective compared to lithium-ion over the long term.

Pros: Good performance in extreme temperatures, high cycle life, less sensitivity to overcharging.

Cons: Cadmium is toxic posing environmental concerns. Relatively low energy density compared to lithium-ion.

solar batteries

Factors Affecting Solar Battery Costs

Several main factors influence the cost of solar batteries, including:

Battery Chemistry: Different battery chemistries have varying costs. Lithium-ion batteries, while more expensive upfront, generally offer better performance and longer lifespans compared to lead-acid or nickel-cadmium batteries.

Energy Capacity: The storage capacity of a battery is a significant factor in its cost. Higher-capacity batteries will typically cost more than those with lower capacities.

Cycle Life: The number of charge-discharge cycles a battery can endure affects its overall cost. Batteries with longer cycle lives generally command higher prices due to their increased durability and longevity.

Efficiency: More efficient batteries may have higher initial costs but can save money over time through reduced charging losses and better overall performance.

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Benefits of Using Solar Batteries

Increased energy independence

With home batteries, solar users can embrace higher-level energy independence by storing excess solar power in batteries. At night or during power outages, homeowners can use energy stored in the batteries to power the home.

As extreme weather events become more frequent, so do power outages. Providing home energy independence will gradually become a necessity to keep homes safe.

Reduce electricity bills

Without a doubt, using solar instead of the grid will save energy bills. By adopting solar batteries, the excess solar power can be stored to use at night, rather than be wasted. As a result, energy bills will be reduced.

In areas that adopt time-of-use electricity charging rates, such as California, home batteries can offset peak rates by charging during off-peak hours and providing stored energy during grid peak hours.

Contribute to a sustainable environment

Solar energy is the most attainable renewable energy source for households. It is clean, limitless, and free. By adopting solar, households are contributing more to a sustainable environment.

The use of solar batteries will extend solar usage, therefore contributing a greater percentage to a clean environment.

To read about more benefits, check out The Advantages and Disadvantages of Solar Batteries for Home Energy Storage.

solar battery backup

Are Solar Batteries Worth the Investment?

While some of the value can be quantified in reduced bills and other monetary values, solar batteries also provide qualitative benefits such as protecting the family during power outages. Electricity is vital to modern lives. Access to electricity in an emergency can be critical.

For more detail on energy bill saving from solar batteries read How to Lower Your Electric Bill with Home Energy Storage.

How to Choose the Right Solar Battery for Your Needs

Define Your Energy Needs: Start by assessing your energy consumption patterns and determining how much energy storage capacity you require. Consider factors such as your daily electricity usage, peak demand times, and any specific backup power needs during outages.

Factor in Cost and Budget: Determine your budget and compare the costs of different battery options, including upfront purchase costs, installation expenses, and ongoing maintenance costs. Consider long-term cost-effectiveness rather than just the initial investment.

Evaluate Incentives: Because of the growing importance of solar energy and battery storage, federal, state, and local governments, as well as regional utility companies, offer a variety of incentive programs. Those can range from covering the initial cost of purchasing home energy management systems to paying customers for accessing stored power during critical periods.

Seek Expert Advice: Consult with solar energy professionals or battery experts to get personalized recommendations based on your specific needs and circumstances. They can provide valuable insights and help you navigate the complexities of choosing the right solar battery.

FranklinWH home batteries

Final Thoughts

Solar batteries are providing increasing value to households. To provide convenience and safety at home, homeowners may find peace of mind with the help of solar batteries.

FranklinWH for Solar Battery Needs

The FranklinWH energy management system is an optimized home energy management system with home batteries that manages the whole home's energy. It integrates solar, grid, battery storage, and a standby generator to supply the home with uninterrupted power.

Compared to solar batteries alone, the FranklinWH energy management system can manage different energy sources to optimize home energy efficiency. Homeowners can monitor and control their home energy generation and usage through the FranklinWH App.

As a result, the FranklinWH system can handle more complicated scenarios and provide more value to the home with peace of mind. Read Everything You Need to Know About Franklin Home Power to learn more about the FranklinWH energy management system.

Frequently Asked Questions About Solar Batteries

What is the lifespan of a solar battery?

The current lifespan of a solar battery typically ranges from 5 to 15 years, depending on factors such as usage patterns, maintenance, and quality of the battery.

How do solar batteries work during power outages?

During power outages, the stored solar energy is used to power essential appliances and devices, providing electricity even when the sun isn't shining.

Can solar batteries reduce my electricity bill?

Yes, solar batteries can reduce electricity bills by storing excess energy generated by solar panels during peak production times and then using them during periods of low production or high electricity demand, thus reducing reliance on grid-supplied electricity.

Are solar batteries environmentally friendly?

Yes, solar batteries are environmentally friendly because they store energy generated from renewable sources such as solar power, reducing reliance on fossil fuels that generate greenhouse gas emissions.

How do I choose the right size solar battery for my home?

To choose the right size solar battery for your home, consider factors such as your energy usage patterns, desired backup power duration, and budget. Read How to Determine the Right Size Solar Battery for Your Needs for more information.

What are the main differences between lithium-ion and lead-acid solar batteries?

Energy Density: Lithium-ion batteries generally have higher energy density, meaning they can store more energy in a smaller and lighter package compared to lead-acid batteries.

Lifespan: Lithium-ion batteries typically have a longer lifespan than lead-acid batteries, with a lifespan ranging from 5 to 15 years compared to 3 to 5 years for lead-acid batteries.

Maintenance: Lithium-ion batteries require minimal maintenance, while lead-acid batteries may need periodic maintenance such as topping up electrolyte levels and checking for sulfation.

Depth of Discharge: Lithium-ion batteries can usually be discharged to a lower depth without affecting their lifespan compared to lead-acid batteries, which are more sensitive to deep discharges.

Charging Efficiency: Lithium-ion batteries generally have higher charging efficiency and can accept charge more rapidly than lead-acid batteries.

What should I consider when installing solar batteries?

When installing solar batteries, consider factors such as your energy usage patterns, desired backup power duration, available space, compatibility with existing solar panels, warranty, and installation costs.

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