6 Best Solar Batteries (2024 Guide)

By Tamara Jude Updated June 1, 2023

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Solar batteries store excess energy generated by your solar power system for later use. Pairing solar batteries with a high-performing system can boost your energy savings and extend your solar system’s benefits. Our team spent more than 70 hours researching solar batteries from leading manufacturers and top solar panel companies. Our guide compares the six best solar batteries for residential homes and offers guidance on shopping for storage options.

Since solar batteries can be a complex subject, we’ve included a “Solar Battery Shopping” section below our brand recommendations with common terms and considerations. You can jump to it using this page’s table of contents at any time.


Top Solar Batteries


Compare Solar Batteries

Below is a comparison of our top solar battery picks. We’ll go into more detail in the sections below.

BatteryOur RatingBattery TypeUsable CapacityContinuous Power RatingDepth of Discharge (DoD)Warranty

Sonnen Eco

4.8 out of 5 stars

LFP

5 kWh to 20 kWh (varies by model)

3 kW to 8 kW

90%

10 years, or 10,000 cycles

Tesla Powerwall 2

4.65 out of 5 stars

NMC

13.5 kWh

5 kW

100%

10 years, unlimited cycles, no throughput clause

LG Chem RESU

4.65 out of 5 stars

NMC

9.8 kWh

5 kW

95%

10 years, 4,000 cycles, or 22.4 MWh throughput clause

Enphase IQ

4.65 out of 5 stars

LFP

3.36 kWh or 10.08 kWh

1.28 kW, 3.84 kW

96%

10 years with a 5-year optional extension, 4,000 cycles (coverage varies by model)

SunPower SunVault

4.6 out of 5 stars

LFP

12 kWh or 24 kWh

6.8 kW to 8 kW

N/A

10 years, 4,000 cycles, or varied throughput clause

Generac PWRcell

4.5 out of 5 stars

NMC

9 kWh to 18 kWh (varies by model)

3.4 kW to 6.7 kW (varies by model)

84%

10 years, varied throughput clause


Highest Usable Capacity: SunPower SunVault

What we like: Known for its high-efficiency solar panels, SunPower offers an exclusive storage solution called the SunPower SunVault. The company provides two battery options for residential installations. The SunVault Storage 13 offers a 12-kilowatt-hour (kWh) capacity and a continuous power rating of 6.8 kilowatts (kW). Continuous power represents how much backup power a battery provides to your home. 

The SunVault Storage 26 boasts a much higher 24-kWh capacity but maintains the same continuous power rating. The 26 model is the largest lithium iron phosphate (LFP) battery in our review. LFP batteries have a longer life span and better safety features than other battery types. 

Both SunVault batteries provide a round-trip efficiency of 85%, meaning they lose 15% of their power when charging. According to the U.S. Energy Information Administration (EIA), the average round-trip efficiency is 80%. While the SunVault ranks above this standard, its efficiency is still low compared to other reviewed batteries.

SunPower does not disclose the depth of discharge (DoD) for its battery storage units. DoD represents how much a battery can drain before shortening its life span. Most manufacturers include DoD ratings to protect the battery. 

Each battery includes a 10-year warranty, which is standard for most solar energy storage options. These batteries also have additional stipulations that could end the warranty early. The SunVault Storage 13 includes a 38-megawatt-hour (MWh) throughput and a 4,000-cycle clause. Your warranty will end if your battery produces 38 MWh of energy or completes 4,000 full charge and discharge cycles before the 10 years. 

The SunVault models have an end-of-warranty capacity of 70%, meaning they will maintain 70% of their outlined storage capacity when the coverage ends. The average end-of-warranty capacity falls around 60%, placing the SunVault batteries at an advantage.

BenefitsDrawbacks

Better-than-average end-of-warranty capacity

Battery is exclusive to SunPower solar systems

Compatible with existing solar systems

Lower round-trip efficiency than other models

Largest usable capacity of our reviewed LFP batteries

Undisclosed DoD information

Read more: SunPower review

 


 

Best Warranty Coverage: Tesla Powerwall 2

What we like: The Tesla Powerwall 2 is one of the most popular solar batteries. It provides 5 kW of continuous energy but uses older, less efficient lithium nickel manganese cobalt oxide (NMC) technology. Unlike other modular solar battery storage, the Powerwall comes in one battery size: a 13.5-kWh model. However, you can add multiple Powerwalls to create a larger backup system.

The Powerwall 2 offers a 90% round-trip efficiency and a DoD of 100%. The 100% DoD rating means the Powerwall can drain completely without reducing its performance. A 100% DoD rating is rare and helps set the Powerwall apart from other home battery options. 

BenefitsDrawbacks

Compatible with existing solar systems

Delayed wait times for Powerwall orders

Leading 10-year warranty with unlimited cycles

Limited availability through Tesla and its dealer network

Up to 10 Powerwalls can be added for backup power

No modular options

Read more: Tesla Solar panel Review


Best Brand Reputation: LG Chem RESU

What we like: The LG Chem RESU-10H has a usable capacity of 9.8 kWh, making it well-suited for homeowners with lower energy needs. The LG Chem is stackable, meaning you can combine batteries to reach a total storage capacity of up to 32 kWh. This battery provides 5 kW of continuous power

The LG Chem RESU-10H includes a 94.5% round-trip efficiency, making it one of the most efficient NMC batteries in our review. The battery also offers a 95% DoD, allowing almost a complete battery drain without damaging the battery capacity or overall life span. Although the LG Chem includes a standard 10-year warranty, it has a rather low throughput clause of 22.4 MWh. 

The LG Chem RESU-10H also includes a 60% end-of-warranty capacity. Although this capacity aligns with industry standards, it’s still lower than other battery banks we reviewed.

BenefitsDrawbacks

Better availability than other battery systems

Lower end-of-warranty capacity

More efficient than other reviewed NMC batteries

Not suitable for homeowners with high energy needs

Depth of discharge is 95%

Throughput clause is lower than other battery modules


Best Lower Power Option: Enphase IQ

What we like: Known for its solar microinverters, Enphase has created the Enphase IQ battery to meet varying energy needs. These batteries work exclusively with Enphase inverters. They also work with gas-powered and solar generators, extending your home’s battery backup options.  

This modular battery comes in four models:

You can increase your stored energy capacity by combining similar units. For example, you can pair the 3 and 3T models and the 10 and 10T options. These batteries have different continuous power ratings to better match customer needs. The 3 and 3T models provide 1.28 kW, while the 10 and 10T batteries offer 1.85 kW. They all share the same 96% round-trip efficiency and 100% DoD. This places the Enphase efficiency higher than SunVault in both efficiency and DoD

Enphase backs its batteries with a 10-year warranty and 4,000-cycle clause. However, the throughput warranties vary by model. The 3 and 3T models provide a 9.8 MWh clause. The Enphase IQ 10 models offer 29.4 MWh for the throughput clause. You’ll also receive an end-of-warranty capacity of 70% for each Enphase IQ battery

Benefits and Drawbacks

BenefitsDrawbacks

Better DoD and round-trip efficiency than SunVault

Additional costs for more warranty coverage

Pairs with solar and gas powered generators

Not suitable for higher-capacity homes

Modular battery options

Must be used with an Enphase inverter


Best Round-Trip Efficiency: Generac PWRcell

What we like: The Generac PWRcell has four system options with varying configurations, usable capacity, and continuous power ratings. Each system is built with 3-kWh modules, offering homeowners more customization options to create the best battery configuration for their homes. 

The Generac PWRcell is the only DC-coupled battery on our list, meaning it stores energy as direct current electricity instead of the alternating current (AC) used to power your home. DC-coupled batteries are more efficient because the energy is only converted from DC to AC once. However, they require a separate inverter. AC-coupled batteries include inverters in their design, making them easier to install. DC-coupled batteries work best in new solar installations rather than existing systems.

Below is a breakdown of each Generac energy storage option:

Generac Model Name Number of Battery ModulesUsable Storage Capacity Continuous Power Rating

PWRcell M3

3

9 kWh

3.4 kW

PWRcell M4

4

12 kWh

4.5 kW

PWRcell M5

5

15 kWh

5.6 kW

PWRcell M6

6

18 kWh

6.7 kW

The PWRcell battery has a 96.5% round-trip efficiency and an 84% DoD. This places the PWRcell at the top of our list for round-trip efficiency. However, its lower DoD makes it one of the least efficient battery options

Each Generac PWRcell includes a 10-year warranty but varies its throughput clauses by model. Here’s an overview of each battery’s throughout clause:

BenefitsDrawbacks

Better customization with smaller modules

Incompatible with existing solar systems

Highest DoD of any other reviewed battery options

Lowest reviewed DoD

Protective cabinet included for indoor and outdoor installations

Poor performance in extreme temperatures

 


 

Best Customization: Sonnen Eco

What we like: The Sonnen Eco offers more modular battery options than other batteries we reviewed. Each battery comes in 2.5-kWh modules that require at least two batteries for the smallest configuration. You can start with a 5-kWh backup system and increase it to 20 kWh. We explain each possible battery configuration below:

Sonnen Eco Battery ModelContinuous Power RatingUsable Capacity

Eco 5

3 kW

5 kWh

Eco 7.5

4 kW

7.5 kWh

Eco 10

8 kW

10 kWh

Eco 12.5

8 kW

12.5 kWh

Eco 15

8 kW

15 kWh

Eco 17.5

8 kW

17.5 kWh

Eco 20

8 kW

20 kWh

Sonnen Eco batteries are bigger and heavier than other solar batteries, so they’re not ideal for homeowners with limited space. For example, the smallest configuration weighs 394 pounds, while the Eco 20 weighs 830 pounds.

In terms of performance, the Eco models offer an 81.6% round-trip efficiency and 90% DoD. Each battery has a 10-year warranty and a 70% guaranteed end-of-warranty capacity. These batteries also include a 10,000 cycle clause, the second largest clause behind the Tesla Powerwall.

BenefitsDrawbacks

10-year warranty or 10,000 cycle clause

Heavier than other battery options

High 90% DoD

Lower continuous power rating than other battery models

Seven modular battery options for more customized storage

Not suitable for homes with limited space or indoor installations


Types of Solar Batteries

Different types of batteries offer varying advantages, battery life, and efficiency ratings. We’ve detailed the two most popular types, lead-acid and lithium-ion solar batteries, below.

Lead-Acid Batteries

Lead-acid batteries have the longest history within the solar industry. Known as deep cycle batteries, this type of battery can charge and discharge constantly without any issues. 

However, lead-acid batteries have their limitations. They have a lower depth of discharge and can only safely discharge up to 50% of their capacity before impacting their life span. These batteries take longer to charge, have bigger and heavier builds, and last only three to five years. Lead-acid batteries work best for off-grid installations. 

Lithium-Ion Batteries

Lithium-ion batteries are more common for residential installations. They use a newer technology that gives them a higher energy density, meaning they contain more energy in compact sizes. These batteries charge faster than lead-acid options and have a higher DoD that ranges between 80% and 100%. Lithium-ion batteries have a life span of up to 10 years. 

Two popular lithium-ion varieties include nickel manganese cobalt oxide (NMC) and lithium iron phosphate (LFP). NMC batteries are more widely used but use older technology. They offer significant power in smaller sizes. However, they contain cobalt which makes them difficult to recycle. LFP batteries use new technology that increases their life span and improves their efficiency. These batteries are more eco-friendly but cost more than NMC options.


How to Shop for a Solar Battery

The right solar battery provides adequate backup power to your home during emergencies and extends your system’s productivity. Several factors, such as battery capacity, power ratings, and DoD, can impact a battery’s usefulness and solar system compatibility. We’ve compiled the most important factors to consider below. 

AC-Coupling vs. DC-Coupling

Most solar batteries are AC- or DC-coupled. Solar panels work by absorbing sunlight, changing it into direct current (DC) energy, and converting it into alternating current (AC) energy for your home. With an AC-coupled system, your solar inverter converts the AC power into DC power for energy storage, then back to AC power when you need to use it. DC-coupled systems only convert this energy once. 

AC-coupled batteries are easier to install and work with existing solar systems. DC-coupled batteries are more complicated to install but more efficient. They’re used for new solar installations

Battery Capacity

Battery capacity represents the amount of power a battery can store for later use. It’s typically measured in kilowatt-hours. Usable capacity differs in that it represents how much energy can be drawn from the battery. Solar batteries must use a percentage of their stored energy to run, reducing their usable capacity

Battery capacity should align with your solar panel system’s production levels. Installing a solar battery that’s too small will cause you to lose excess energy. Using one that’s too large will waste valuable storage capacity.

Depth of Discharge

Solar batteries with a high depth of discharge (DoD) maximize your storage capability and improve your energy savings. Using a solar battery with a lower DoD lowers your energy savings potential, leading to wasted energy storage. Lead-acid batteries only offer 50% DoD while lithium-ion storage options range from 80% to 100% DoD

Price

Battery pricing varies among companies, third-party installers, and authorized dealers. Newer lithium-ion batteries cost more than lead-acid options. Though more cost-effective, lead-acid batteries need to be replaced more often. 

Federal and local solar incentives offer additional solar battery savings. Homeowners can receive up to 30% off solar battery costs with the federal tax credit. This includes a solar battery purchased with a solar system or as a stand-alone option. Homeowners who already have a solar energy system can apply for the credit when upgrading their backup power. States, cities, and utility companies offer additional rebates and incentives. We recommend checking the Database of State Incentives for Renewables and Efficiency (DSIRE) for available incentives in your area.

Power Ratings

Power ratings, expressed in kilowatts, measure the energy your battery produces. You’ll see two types of power ratings listed for a battery: peak and continuous. 

Peak power represents the amount of electricity a battery can produce instantaneously. Batteries with a high capacity but lower power rating can power smaller devices longer. Batteries with low capacities but high power ratings provide stronger bursts of energy for limited time frames. 

The continuous power rating represents the amount of time a battery can power a device. Most batteries offer 5 kW of continuous energy. Anything higher indicates a more powerful battery. We focus on continuous power ratings to help homeowners determine the best battery options for running their homes longer and more effectively. 

Round-Trip Efficiency

We recommend matching high-performing residential solar panels with efficient solar batteries to make the best use of your excess energy. Look for solar batteries with a round-trip efficiency of 80% or higher. The higher the round-trip efficiency, the less power is lost when your battery charges. 

Warranty

Check each warranty for its time frame and any additional clauses that could end your coverage early. Throughput and cycle clause thresholds could be met before the end of your contract. Consider batteries with only time frame-based coverage or warranties with higher cycle and throughput clauses. 

In addition, review the end-of-warranty clauses to determine your estimated battery output after the warranty ends. Constant cycling and discharging will wear down a battery’s production. Most batteries have 60% end-of-warranty capacity guarantees. We recommend buying a solar battery that exceeds this threshold to maximize your solar storage options for longer.


Our Recommendation

The right energy storage system extends your solar system’s efficiency, provides sufficient backup power, and boosts energy savings. The SunPower SunVault offers the highest usable capacity for a single battery and supports homes with higher energy usage. Tesla Powerwall, one of the most popular solar batteries, includes the best warranty protection with 10 years of battery use. If your home has lower energy needs, the LG Chem RESU is your best option. We recommend comparing at least three solar batteries to find the best fit for your home. 

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Solar Batteries FAQ

Which solar battery has the longest life span?

Lithium-ion batteries have the longest life span, lasting up to 10 years. Lead-acid batteries last three to five years at most.

How many years can Tesla solar batteries last?

The Tesla Powerwall 2 solar battery can last up to 10 years with proper maintenance and care.

What are the best batteries to store solar energy?

Lithium-ion batteries are the best batteries for residential solar energy storage. They have a higher energy density, meaning they store more energy in smaller spaces. They offer better efficiency and have longer life spans than lead-acid solutions. However, lithium-ion batteries are also the most expensive.

Can you run a whole house on solar and batteries?

Yes, you can run your whole house on solar power and batteries with proper planning. By pairing high-efficiency solar panels with large-capacity solar batteries, you can generate enough energy to run your home with panels by day and batteries overnight. Many people choose to go “off-grid,” meaning they cut ties with traditional utility companies completely and live on self-generated solar energy. 

How We Chose the Top Solar Batteries

We reviewed dozens of solar batteries and their manufacturers. We then formulated a rating system based on several factors. We evaluated cycle efficiency, usable capacity, warranty length, depth of discharge, and end-of-warranty performance. We assessed each manufacturer’s product catalog for size, variety, and stackability. We also compared each battery’s performance metrics to ensure they matched or exceeded industry standards.

We researched each company’s reputation, solar industry knowledge, and business experience. We also spoke directly to representatives to better understand the buying process. Finally, we learned about each manufacturer’s installation process, whether offered directly through the company or a third-party installer. 

 Read more: Our Methodology