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Written byTamara JudeUpdated 04/17/2024
Tamara Jude
Tamara Jude is a seasoned content writer with more than seven years of experience in research and content production. She specializes in the solar energy, home warranty, and windows categories. Her interest in home improvement began as a child, when she regularly completed home projects alongsid…
See full bioSolar-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.
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
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.
Our Solar Battery Top Picks
SunPower SunVault
Most Powerful
4.7
SunPower SunVault
Most Powerful
4.7
Pros
- Has the largest usable capacity in our review
- Offers two size options for better customization
- Uses newer LFP technology
Cons
- Does not disclose DoD information
- Limited to SunPower solar systems
- Offers a lower end-of-warranty capacity
Why We Choose the SunPower SunVault
SunPower is known for having the most efficient solar panels, and it also has one of the largest storage options in our review. Its high-capacity LFP battery guarantees higher efficiency and a longer life span than other options.
The SunPower SunVault comes in two sizes to suit your energy needs: the SunVault Storage 13 and SunVault Storage 26. The 13 model has a usable capacity of 13 kWh and a continuous power rating of 6.8 kW. The 26 model is the largest LFP battery in our review, with 26 kWh capacity and 6.8 kW of continuous power.
Battery Models
- SunVault Storage 13: This model offers a usable capacity of 13 kWh.
- SunVault Storage 26: The largest SunVault battery provides 26 kWh of usable capacity.
Specifications
- Continuous power rating: 6.8 kW
- Depth of discharge (DoD): N/A
- Round-trip efficiency: 85%
- Usable capacity: 13 kWh or 26 kWh (varies by model)
Warranty & Installers
Warranty
Each SunVault model includes a standard 10-year warranty, 70% end-of-warranty capacity, and an unlimited cycle clause.
Installers
SunPower’s batteries are exclusive to its solar power systems. You need to order through SunPower or one of its authorized dealers.
Tesla Powerwall 2
Best Warranty
4.8
Tesla Powerwall 2
Best Warranty
4.8
Pros
- Add up to 10 Powerwalls for larger backup capacity
- Includes a 10-year warranty with an unlimited cycle clause
- Integrates into existing solar systems
Cons
- Long wait times for Tesla Powerwall ordering
- Must use a Tesla-certified installer
- Only comes in one size
Why We Choose the Tesla Powerwall 2
Known worldwide for its electric vehicles, Tesla shifted its focus to the solar industry in 2015. The Tesla Powerwall battery has become one of the most popular solar batteries. The latest model, Tesla Powerwall 2, has one of the industry’s best warranties, offering 10 years of coverage without restrictions.
The Tesla Powerwall 2 is a single 13.5 kWh battery. However, you can stack multiple batteries to meet your power needs. The battery offers 5 kW of continuous energy and uses Lithium Nickel Manganese Cobalt Oxide (NMC) technology.
Battery Models
The Tesla Powerwall 2 comes in one model offering 13.5 kWh of usable capacity.
Specifications
- Continuous power rating: 5.8 kW
- Depth of discharge (DoD): 100%
- Round-trip efficiency: 90%
- Usable capacity: 13.5 kWh
Warranty & Installers
Warranty
Tesla backs its batteries with one of the best warranties available. Customers receive 10 years of coverage with an unlimited cycle clause and end-of-warranty capacity of 70%.
Installers
You can purchase the Powerwall 2 directly from the company with a new Tesla solar panel installation or through the Tesla Powerwall Direct program. Powerwalls are also available through Tesla-certified installers and solar companies, including ADT Solar and Sunrun.
SonnenCore+
Best Add-On Battery
4.9
SonnenCore+
Best Add-On Battery
4.9
Pros
- Includes a minimum 10-year warranty with a 10,000 cycle clause
- Uses advanced LFP technology for improved efficiency
- Works with new or existing solar systems
Cons
- Cannot mix and match modules of different sizes
- Has a lower round-trip efficiency than other brands
- Not all models are made for outdoor use
Why We Choose Sonnen
Sonnen offers several modular battery models that can connect to build a larger storage system. Module size varies per battery model but starts as low as 10 kWh usable capacity with a maximum of 60 kWh. The company offers various models designed for indoor or outdoor use. However, some models, such as the SonnenCore+, are made for indoor installations exclusively. The SonnenEvo model is AC-coupled, making it easy to integrate into an existing solar system. The EcoLinx can sync with smart-home automation technology and adjust backup power use based on the time of day and weather.
Battery Models
- SonnenCore+: The SonnenCore SCORE-P10 has a 10-kWh usable capacity while the SCORE-P20 doubles in capacity to 20 kWh. You can stack up to three units for a total capacity of up to 30 kWh or 60 kWh.
- SonnenEvo: The SonnenEvo offers a usable capacity of 10 kWh and can stack up to three units for up to 30 kWh.
- EcoLinx: The Sonnen EcoLinx 1.5 line offers capacity options between 12 kW and 20 kW. The Sonnen EcoLinx 30 includes only one model with a usable capacity of 30 kWh.
Specifications
- Continuous power rating: 4.8kW–14.4kW (varies by model)
- Depth of discharge (DoD): 100%
- Round-trip efficiency: 81.60%–85.80% (varies by model)
- Usable capacity: 10 kWh–30 kWh (varies by model)
Warranty & Installers
Warranty
The SonnenEVO and SonnenCore+ include a 10-year warranty with a 10,000-cycle clause plus an end-of-warranty capacity of 70%. The ecoLinx includes an extended 15 years of coverage with a 15,000-cycle clause.
Installers
You can purchase Sonnen batteries from Sonnen-certified installers and select solar providers.
Enphase IQ
Best for System Monitoring
4.8
Enphase IQ
Best for System Monitoring
4.8
Pros
- Compatible with gas or solar generators
- Integrated high-tech Enphase inverter technology
- Monitoring technology that switches between power modes
Cons
- Added costs for additional warranty coverage
- Only works on solar systems with Enphase microinverters
- Not suited for homes with high-capacity needs
Why We Choose the Enphase IQ
The Enphase IQ comes with integrated system monitoring, making it easier to track your battery’s performance. Its innovative software can automatically switch between power modes based on your home’s energy needs, including switching on backup power during an outage. Enphase IQ is integrated with the company’s well-known solar microinverter technology. The battery is AC-coupled, making it ideal for existing solar systems. However, it can be used only on solar systems with Enphase microinverters.
Battery Models
- Enphase IQ 3: This module has a capacity of 3.36 kWh and comes in a large, heavy storage system.
- Enphase IQ 3T: This model has the same capacity as the previous model but with a slimmer design.
- Enphase IQ 10: This battery has a usable capacity of 10.08 kWh and comes in a heavy design.
- Enphase IQ 10T: This is the slimmer version of the 10.08 kWh model.
- Enphase IQ 5P: This all-in-one model includes a 5.0 kWh usable capacity and six integrated microinverters.
Specifications
- Continuous power rating: 3.84 kW
- Depth of discharge (DoD): 96%
- Round-trip efficiency: 100%
- Usable capacity: 3.36 kWh–10.08 kWh (varies by model)
Warranty & Installers
Warranty
Enphase 3/3T and 10/10T models include a standard 10-year warranty and a guaranteed end-of-warranty capacity of 70%. However, they have a cycle clause of 4,000 cycles. The 5P has a 15-year limited warranty with a cycle clause for up to 6,000 cycles.
Installers
You can buy Enphase energy storage systems from the company’s online shop and its sales team. You can also purchase through top solar installers, including ADT Solar, Freedom Solar Energy, Green Home Systems, and Semper Solaris.
Generac PWRcell
Best Customization
4.6
Generac PWRcell
Best Customization
4.6
Pros
- Has one of the highest round-trip efficiency ratings in our review
- Includes a durable NEMA 3R cabinet for indoor or outdoor use
- Offers multiple modular configurations for better customization
Cons
- More prone to fires when misused, due to its NMC chemistry
- Incompatible with existing solar systems
- Provides lower DoD percentage compared to other batteries
Why We Choose the Generac PWRcell
The Generac PWRCell is one of the few DC-coupled batteries on this list. It has one of the highest round-trip efficiencies, topping out at 96.5%. Generac offers top customization options, using 3-kWh models in four distinct configurations. The entire system includes a durable battery cabinet for indoor and outdoor installations. The cabinet can house up to six battery modules for extended capacity.
Battery Models
The Generac PWRcell uses 3 kWh modules in four different capacities:
- PWRcell M3: This model provides 9 kWh of storage capacity with three modules and a continuous power rating of 4.5 kW.
- PWRcell M4: This four-module battery has a larger 12 kWh of storage capacity with 6 kW of continuous power.
- PWRcell M5: With five total modules, this battery provides 15 kWh of storage capacity and a continuous power rating of 7.5 kW.
- PWRcell M6: The largest six-module battery offers 18 kWh of storage capacity with 9 kW of continuous power.
Specifications
- Continuous power rating: 3.4 kW–6.7 kW (varies by model)
- Depth of discharge (DoD): 84%
- Round-trip efficiency: 96.5%
- Usable capacity: 9 kWh–18 kWh (varies by model)
Warranty & Installers
Warranty
Generac includes a 10-year warranty with each battery option and 70% end-of-warranty capacity. These batteries also include a 7.56-MWh throughput per battery module. Below are the total clauses for each battery model:
- PWRcell M3: 22.6 MWh throughput clause
- PWRcell M4: 30.2 MWh throughput clause
- PWRcell M5: 37.8 MWh throughput clause
- PWRcell M6: 45.3 MWh throughput clause
Installers
Generac PWRcells are available through the Generac website, various solar installation companies, and Generac-certified installers.
LG Chem RESU
Best Availability
4.6
LG Chem RESU
Best Availability
4.6
Pros
- Provides an excellent round-trip efficiency
- More compact design than other batteries reviewed
- Works well with households with lower power needs
Cons
- Includes models with a lower end-of-warranty capacity
- Lower throughout clause than other battery options
- Not compatible with all solar systems
Why We Choose the LG Chem RESU
Although LG no longer manufactures solar panels, the company still produces high-powered batteries for whole-home protection. This DC-coupled battery has a compact design, making it suited for homes with limited space. The LG Chem batteries offer modular configurations and include two models for home installations. The newest Prime models offer compatibility with popular solar inverter brands, including SMA and SolarEdge. LG maintains a large network of installers, making its batteries available to more customers nationwide.
Battery Models
- LG RESU Gen2: The two models in this line, LG RESU 10H-R and RESU 10H-C, provide 9.8 kWh usable capacity.
- LG RESU 10H PRIME: This Prime model comes with a 9.6-kWh usable capacity.
- LG RESU 16H PRIME: The largest Prime model available has a usable capacity of 16 kWh.
Specifications
- Continuous power rating: 5.0 kW–7.0 kW (varies by model)
- Depth of discharge (DoD): 95%
- Round-trip efficiency: 95%
- Usable capacity: 9.8 kWh–16 kWh (varies by model)
Warranty & Installers
Warranty
The LG RESU Gen2 models include a 10-year warranty with a 60% end-of-warranty capacity. The LG RESU Prime models also include 10 years of coverage but offer a higher 70% end-of-warranty capacity. The throughput clauses vary by model, as outlined below:
- LG RESU Gen2: 22.4 MWh throughput clause
- LG RESU 10H PRIME: 32 MWh throughput clause
- LG RESU 16H PRIME: 54 MWh throughput clause
Installers
You must use a certified LG installer for your installation. This includes third-party installers or solar providers such as Sunrun.
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.
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.
Compare the Best Solar Batteries
Here’s a breakdown of the key features of top solar battery picks:
| Battery | Our Rating | Usable Capacity | Continuous Power Rating | Depth of Discharge (DoD) | Round-Trip Efficiency | Warranty |
|---|---|---|---|---|---|---|
SunPower SunVault | Most Powerful | 13 kWh or 26 kWh | 6.8 kW | N/A | 85% | 10-year warranty, unlimited cycle clause |
Tesla Powerwall 2 | Best Warranty | 13.5 kWh | 5.8 kW | 100% | 90% | 10 years, unlimited cycles |
Sonnen | Best Add-On Battery | 10 kWh–30 kWh (varies by model) | 4.8 kW–14.4 kW (varies by model) | 100% | 81.60%–85.80% (varies by model) | 10 to 15-year warranty, or 10,000–15,000 cycles (varies by model) |
Enphase IQ | Best for System Monitoring | 3.36 kWh–10.08 kWh (varies by model) | 3.84 kW | 96% | 100% | 10 to 15-year warranty, 4,000–6,000 cycles (varies by model) |
Generac PWRcell | Best Customization | 9 kWh–18 kWh (varies by model) | 3.4 kW–6.7 kW (varies by model) | 84% | 97% | 10 years, 7.56 MWh throughput clause per battery module (varies by model) |
LG Chem RESU | Best Availability | 9.8 kWh–16 kWh (varies by model) | 5.0 kW–7.0 kW (varies by model) | 95% | 95% | 10 years, throughput clauses between 22.4–54 MWh throughput clause (varies by model) |
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
How do I choose the right solar battery?
You should consider several factors when choosing a solar battery. The battery needs to be large enough to store and discharge your energy effectively. You should also consider your backup power needs, how many high-power appliances are in your home, and whether you’re a new or existing solar customer. A solar battery or panel installer can review your energy usage and select the best battery for your home.
What are the benefits of a solar battery?
Solar batteries store excess energy generated by your solar panels to use at night, on low-sunlight days, or during power outages. They’re an excellent alternative to a net-metering program, which pays customers to sell excess energy back to their utility company. Without a solar battery, you miss out on additional long-term energy savings.
What is the best solar battery?
Lithium-ion batteries are considered the best solar battery option for most homeowners. Lithium Nickel Manganese Cobalt Oxide (NMC) and Lithium Iron Phosphate (LFP) are the most common lithium varieties. There are more NMC batteries available since it’s an older technology, but LFP options are becoming more popular.
Can I install a solar battery myself?
No, we don’t recommend installing a solar battery yourself. Hire a professional solar installer for the best results.
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.
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