Solar-powered batteries store excess electricity for use at night, during power outages, or when utility rates are high. They help expand your solar energy system’s efficiency and offer additional long-term energy savings.

Our team spent 50 hours researching the best solar batteries from the top solar energy companies and leading home battery manufacturers. We picked SunPower SunVault, Tesla Powerwall, and Sonnen batteries as top choices. However, the best battery for your home will depend on your energy needs, budget, and other preferences. Learn more about our complete list of the best solar batteries for homeowners.

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The 6 Best Solar Batteries

Here are the best solar batteries based on our research:

• SunPower SunVault: Most Powerful
• Tesla Powerwall 2: Best Warranty
• SonnenCore+: Best Add-On Battery
• Enphase IQ: Best for System Monitoring
• Generac PWRcell: Best Customization
• LG Chem RESU: Best Availability

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Key Differences in Solar Batteries

• Continuous power rating: This rating represents how long a battery can provide continuous power. The higher the rating, the better the power production. The industry standard is 5 kilowatts (kW) of continuous power.
• Depth of discharge: Depth of discharge (DoD) measures how much of the battery can be used relative to its full capacity. Battery manufacturers typically limit DoD to protect the battery’s longevity. A higher DoD indicates a better-quality battery. 
• End-of-life capacity: This measurement indicates how much storage capacity will remain at the end of your battery’s warranty. The standard end-of-warranty capacity is 60% of the battery’s listed capacity. Look for battery storage solutions that meet or exceed this level.
• Coupling: Different coupling configurations work better with certain home solar systems. Alternating current (AC) coupled batteries work as an add-on to existing systems. Direct current (DC) coupled batteries integrate into a new solar system. 
• Modular design: A modular battery connects in a series to create a larger energy storage system. You can add or subtract modular batteries to best suit your energy needs. Some companies offer stand-alone or modular battery options. 
• Round-trip efficiency: Round-trip efficiency measures the amount of electricity that remains after charging the battery, as the process uses some stored energy. According to the U.S. Energy Information Association (EIA), the industry average is around 80%. 
• Warranty clause: Most battery manufacturers have warranty clauses outlining the number of cycles or throughput your battery can reach in its lifetime. A cycle is the process of your battery fully charging and discharging. Throughput measures the total energy your battery can generate in its lifetime. When you reach either of these clause limits, your warranty will end.

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Our Solar Battery Top Picks

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Types of Solar Batteries

Solar batteries have different chemistries that provide varying advantages and disadvantages. Let’s take a closer look at the two most common battery types: lead-acid and lithium-ion. 

Lead-Acid Batteries

Lead-acid batteries have a long history in the solar industry. They’re deep-cycle batteries, which are designed to be drained of their capacity regularly. These batteries are larger, heavier, and take longer to charge than lithium. They also have a shorter life span. Lead-acid batteries aren’t popular for residential systems but are often used for off-grid installations, especially vacation properties. 

Lithium Batteries

Lithium batteries are more compact than lead-acid batteries, making them ideal for smaller homes and tight spaces. They also last longer and charge quicker. There are two main types of lithium batteries: lithium nickel manganese cobalt oxide (NMC) and lithium iron phosphate (LFP).

NMC batteries are the most common lithium variety. They use an older but trusted technology. NMC batteries are cheaper to make and have average power ratings. LFP batteries have newer chemistry that retains stored energy more efficiently. These batteries have a higher power rating but cost more to produce. LFP batteries are also safer than NMC options because they don’t contain cobalt, which can cause fires if the batteries are misused. LFP modules are recyclable and better for the environment.

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How To Choose a Solar Battery

Here are some key factors to consider as you search for the ideal battery storage system. 

AC- and DC-Coupling

Your solar power system generates direct current (DC) electricity that must be converted to alternating current (AC) to use in your home. An AC-coupled system converts energy to AC at the inverter, converts it back to DC for storage, and converts it to AC again when it’s ready to be used. In a DC-coupled system, energy is converted only once.

AC-coupled batteries can easily be added to existing solar panel systems, including Tesla solar systems, but provide lower efficiency than DC-coupled batteries because some energy is lost during the conversion process. DC-coupled batteries are more efficient and can pull energy from solar panels even when the grid is down. They’re ideal for new solar systems but are complicated to install and can increase the cost of installing a solar system in your home.

Battery Capacity

Battery capacity is the amount of power a solar battery can store. It’s measured in kilowatt-hours (kWh). The usable capacity represents how much energy can be used from the battery. This number is lower than the battery’s actual capacity because some energy must be used to run the battery.  

It’s essential to match your battery capacity to the amount of energy your solar system generates. You’ll waste that valuable extra energy if your solar battery system is too small, but you won’t use your battery’s full capacity if it is oversized based on your solar power output. We recommend working with a professional solar or battery installer to find the right backup system for your home.

Cost

Solar battery costs vary based on several factors, including brand, chemistry, and size. According to the National Renewable Energy Laboratory (NREL), the average solar battery costs around $16,007 but can increase to $18,791 with added installation fees and permitting. 

State and federal solar incentives could help reduce battery system costs during installation. Some areas offer battery-specific rebates or credits to homeowners. The federal solar tax credit reduces costs by up to 30% for new solar systems or stand-alone battery installations. We recommend checking the Database of State Incentives for Renewables & Efficiency (DSIRE) for an up-to-date list of incentives in your area. 

Depth of Discharge

The industry standard is 80%–100% for lithium-ion batteries and 50% for lead-acid options. Many manufacturers limit DoD because repeatedly draining a battery of its full capacity shortens its life span while discharging at a lower percentage preserves it.

Power Rating

Power ratings measure the amount of electricity produced in a given time, expressed in kilowatts (kW). Batteries with a higher power rating can run several high-power appliances at once. There are two types of power ratings: peak and continuous. 

• Continuous power: The amount of energy a battery can produce in a certain period. Our reviews focus on this metric over peak power because it better measures how long your battery can effectively power your home.
• Peak power: The maximum amount of power a battery can produce instantly.

Batteries with a low capacity but a high power rating can power devices in short bursts but don’t provide long-term power. Batteries with high capacity but a low power rating can run small devices for much longer.

Round-Trip Efficiency

A higher percentage means less power loss from charging, indicating a more efficient battery bank. You’ll waste less energy with an efficient solar energy storage system.  

Warranty

Solar batteries have a standard 10-year warranty. Some manufacturers add throughput or cycle clauses that may end the warranty early. Review the batteries’ warranty terms and find options with higher thresholds. 

You should also review the end-of-warranty terms for projected capacity. The more solar batteries are charged and recharged, the less effective they become.

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Compare the Best Solar Batteries

Here’s a breakdown of the key features of top solar battery picks:

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Our Conclusion

The SunPower SunVault tops our lists for its excellent single-model usable capacity and overall performance. The Tesla Powerwall 2 costs over $10,000 but is an excellent choice for those who want solid battery performance with a long warranty. The Sonnen Eco offers easy integration into new or existing solar systems. We recommend working with a professional solar or battery installer to find the right solar storage system for your needs. Compare at least three solar batteries before making your final purchase.

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FAQ About Solar Batteries

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Our Rating Methodology

We aim to provide comprehensive and unbiased reviews to our readers. This means earning your trust through transparent reviews and data to back up our recommendations. Our rating system for solar batteries is on a 100-point scale based on five factors:

• Depth of discharge (20 points): Does the company disclose its depth of discharge (DoD) rating? Does the DoD meet the industry standard of 80%? The higher the rating, the higher the score. 
• Round-trip efficiency (20 points): How efficient is the battery? Does it meet or exceed the industry standard of 80%? The higher the round-trip efficiency, the more points we awarded.
• Battery chemistry (15 points): We awarded more points to Lithium Iron Phosphate (LFP) batteries than Lithium Nickel Manganese Cobalt Oxide (NMC) batteries due to their higher efficiency and longer lifespan.
• Battery options (15 points): Are there multiple battery sizes for better customization, or is only one size available? 
• End-of-warranty capacity (15 points): How powerful will the battery be at the end of its warranty? Does the projected end-of-warranty capacity meet the industry standard of 60%? We awarded more points to batteries with higher end-of-warranty capacities.
• Warranty length (15 points): How long is the battery’s warranty? Does it meet or exceed the standard 10-year warranty? Batteries with the longest, most comprehensive warranties ranked higher.