Compare 5 Best Flexible Solar Panels (2023 Reviews and Buyer’s Guide)
By Christian Yonkers /
In this review of the best solar batteries, you’ll learn:
Each product and or company featured here has been independently selected by the writer. You can learn more about our review methodology here. If you make a purchase using the links included, we may earn commission.
If you’re looking for improved solar savings and blackout protection for your home, then adding a solar battery to your solar array is a great option. Most people know about the Tesla Powerwall, and while it’s a great product, it doesn’t mean it’s the best solar battery out there.
In this guide, we’ll be discussing what we believe are the top five best solar battery manufacturers to choose from for home solar power systems. These include the following:
We’ll explain why each is a great option for these purposes and help you decide which is the best one for your needs below. You can click on the drop-down menus under each battery option for more detailed information.
Tesla is a leader in the industry in terms of technology, and the different Powerwall batteries are a clear reason why. The energy storage systems from Tesla are sleek, perform better than most other options on the market and come with some impressive technology that makes them super convenient to use. The high demand means the waitlist for products is quite long, but we feel they’re still some of the best options available.
We recommend Tesla solar batteries for homeowners who want the best of the best and don’t mind waiting a few months for supply to catch up with demand.
What We Like
There are so many positive things to say about Tesla’s solar batteries. First off, they’re expensive, but the cost per kilowatt-hour (kWh) is well below the industry average at just $851. In fact, they’re some of the most affordable backup batteries when taking capacity into account.
Tesla’s solar batteries have outstanding performance specifications. The capacity is above the industry standard—13.5 on the Powerwall+ as opposed to the typical 5.1 kWh—and they have the highest total capacity we’ve seen.
These are modular batteries, so you can connect 10 Powerwalls in series for a maximum storage capacity of 135 kWh. That means they should keep just about any home powered through a blackout, even if you have an above-average electricity consumption rate.
The batteries have an above-average peak output for high-demand homes. They have some impressive technology included at no cost, and they also come equipped with features like Storm Watch, which automatically recharges your batteries if severe weather is headed your way.
The downside to buying a solar battery from Tesla is the delay you’re likely to experience between ordering and installation. Tesla’s competitors are likely running into the same supply chain issues, but they have a much lower demand for their products, so they can often be installed shortly after ordering.
Tesla has also been in the news in the past few years for social sustainability issues, including claims of racism in its production facilities. These claims haven’t been substantiated yet, but this is a potential negative to consider.
Read our full review of Tesla for more information.
Tesla has two solar batteries in production: the Powerwall and the Powerwall+.
The table below includes a comparison of the two battery options from Tesla to help you decide which might be best for your home.
|Tesla Powerwall||Tesla Powerwall+|
|Storage Capacity (Per Battery)||13.5 kWh||13.5 kWh|
|Total Capacity (In Series)||135 kWh||135 kWh|
|Cost Per kWh||$629||$851|
|Continuous Power Output||5 kWh||7 kWh|
|Peak Power Output||10 kWh||9.7 kWh|
Tesla’s battery warranty is close to the industry standard. The warranty term is 10 years, which is average, and the guaranteed remaining efficiency at the end of the warranty is 70%, which is just a touch below average.
Tesla has a good reputation for responding to warranty claims, so you’re unlikely to run into major issues if you do have a problem with your battery performance. On average, your Tesla battery should last a minimum of 10 years, but many customers find that they last 15 to 20 years.
Tesla Powerwalls cannot be purchased separately for a DIY installation, which is the case for most batteries on the market. Much like it does for its solar panels, the company uses a massive network of third-party installers to distribute and install its batteries, so you should have no problem finding an installer in your area to tackle the installation.
Tesla also recently started allowing battery installations independently of solar panels, so you can now have your Powerwalls installed as backup electric generators even if you don’t have a solar panel system on your roof. The best part is that you can still take solar incentives and rebates that apply.
|Better Business Bureau (BBB) Rating|
|Average Cost ($-$$$$$)|
|Solar Panels, Solar Batteries, EV Chargers, Solar Roof Shingles, System Monitoring|
Panasonic is a major player in the industry, and its batteries are some of the best alternatives to the more well-known Powerwalls from Tesla. The batteries provide outstanding value for the money, with below-average pricing per kWh, some of the highest per-battery capacities in the industry and outstanding performance specifications.
Panasonic has a slightly below-average warranty, but we still think it’s a great option for anyone looking to get the most bang for their buck.
What We Like
Some of the best things about Panasonic’s solar batteries are the high capacity and the above-average performance specs. The Evervolt 2.0 battery has a massive capacity of 17.5 kWh, which is more than double the industry average. The batteries are expensive, but on a per-kWh basis, you’ll pay just $857, which is around 25% lower than most other battery options.
Panasonic’s batteries have an industry-leading continuous power output of 9.6 kWh and a peak output of 12 kWh, so they’re a great option for you if you have high energy demands or multiple people living in your home. They’ll be able to run multiple appliances and electronics — including electric vehicle (EV) chargers — at once without you having to worry about damaging your equipment.
Panasonic’s batteries can also be connected in series for a total storage capacity of 102 kWh, so it’s a great option for keeping excess energy at the ready for long blackouts or offsetting expensive energy consumption at night.
The biggest downside to purchasing a Panasonic battery, in our opinion, is the upfront cost per battery. Even though the Evervolt series has a low per-kWh battery, it also has a high capacity, which means a minimum cost of around $15,000.
The least amount of money you can spend on a Panasonic battery is around 300% of what you might spend on smaller batteries. As such, we feel this battery provides outstanding value for the money, but it’s not ideal if you only want emergency backup power.
Read our full review of Panasonic for more information.
Panasonic manufactures two main solar batteries: the EverVolt and the EverVolt 2.0.
The table below includes some key information about these two options in case you can’t decide if the original EverVolt or the 2.0 is right for your home.
|xxx||Panasonic EverVolt||Panasonic EverVolt 2.0|
|Storage Capacity (Per Battery)||11 kWh maximum||17.5 kWh maximum|
|Total Capacity (In Series)||70 kWh||102 kWh|
|Cost Per kWh||$856||$856|
|Continuous Power Output||4.6 kWh||17 kWh|
|Peak Power Output||5 kWh||10 kWh|
The warranty Panasonic offers for its batteries is one of the areas where the company falls a bit short. The warranty term is 10 years, which is right in line with the industry standard. However, the guaranteed efficiency remaining at the end of the term is just 60%, whereas most competitors guarantee 70% or higher.
Much like Tesla, Panasonic uses third-party installers to handle its installations. Although not as many solar companies carry Panasonic batteries as Tesla Powerwalls, you still shouldn’t have any problems finding an installer near you that does carry them.
|Average Cost ($-$$$$$)|
|Solar Panels, Solar Batteries|
SunPower is one of the biggest and most trustworthy names for solar panels in the entire industry, and it somewhat recently started offering its SunVault storage system to complement its panels. Since SunPower has a nationwide presence and installation partners in all 50 states, the SunVault remains one of the most widely available solar batteries for homes.
SunPower’s SunVault is quite expensive on a per-battery basis, but we still feel that the quality is worth the investment. We’d recommend this battery for solar customers who want high performance and great availability from the trusted SunPower brand name.
There are plenty of things to love about the SunPower battery. To start, the batteries come in large capacities, ranging from 13 kWh up to a massive 52 kWh. That means you have the option for higher-than-average storage capacity, all in a single battery encasement.
We also love the performance specs from the SunVault system, including the above-average continuous power and peak power tolerances of 6.8 kWh and 10 kWh, respectively. These batteries should be able to handle energy demands for just about any home, even if you have multiple people in your house using electricity constantly.
SunPower is also a viable option for just about every U.S. resident. The company has one of the largest networks of certified installers in the country, so no matter where you live, you should have access to it. The SunVault can also be installed exclusive of panels, so it’s an option for off-grid power even if you haven’t invested in a full solar system.
There are two primary things that could be better with the SunPower battery. Most importantly, the round-trip efficiency is below average, and there’s no depth of discharge (DoD) rating made public. The low round-trip efficiency of 85% means some of the renewable energy your panels generate will be lost in the transition to storage, so this battery isn’t ideal in areas where panel efficiency needs to be optimized.
The lack of DoD information isn’t a huge deal, but it does mean the amount of energy available of the stated capacity you can use to power your home is unknown. Ultimately, your available storage could be below the stated 13 to 52 kWh.
Read our full review of SunPower for more information.
SunPower currently only offers one home battery option: the SunVault. Much like SunPower’s panels, the battery has above-average performance specifications, including a 52 kWh maximum capacity per battery and continuous and peak power outputs of 6.8 kWh and 10 kWh, respectively. That means it’s a good option for homes that use a lot of energy.
The table below can be used to compare SunPower’s solar battery with others on our list.
|Storage Capacity (Per Battery)||13–52 kWh|
|Total Capacity (In Series)||52 kWh|
|Cost Per kWh||$1,000|
|Continuous Power Output||6.8 kWh|
|Peak Power Output||10.0 kWh|
SunPower offers a 10-year warranty for its storage systems, which is in line with the industry average. After the warranty term, your SunVault system is guaranteed to have retained 70% of its starting efficiency, which is also average.
The installation options available are really where SunPower shines. Since it’s a leading manufacturer of solar panels in the U.S., it has an enormous nationwide network of installers that can offer its products. SunPower’s batteries are some of the most widely available in the country.
SunPower storage solutions aren’t available for DIY installation, but you can have them installed independently of solar panels if you just want a capable electric generator.
|Better Business Bureau (BBB) Rating|
|Average Cost ($-$$$$$)|
|Brands of Solar Equipment Offered|
|Solar Panels, Solar Batteries, EV Chargers, System Monitoring|
|25-year all-inclusive warranty|
Unlike our top two solar battery manufacturers, Generac doesn’t manufacture solar panels and instead focuses entirely on battery banks and off-grid generators. The Generac PWRCell is a widely-known product, most notable for its high storage capacity and add-on options, like the PWRGenerator and the PWRManager.
We recommend Generac solar batteries for anyone who’s looking for a one-stop shop for off-grid power, especially if you want a high-capacity battery with an outstanding efficiency rating.
As mentioned above, Generac stands out because of its efficiency rating and its expandability with add-on products.
The PWRCell from Generac has an industry-leading round-trip efficiency of 96.5%. That means it will help you make the most of the solar energy you collect with your panels and can provide maximum power for your home in blackout or low-sun conditions. This makes it ideal for areas without net metering and solar customers who see low-sun conditions often.
Generac also makes a handful of solar battery add-on products to manage power more efficiently and maximize your off-grid power. It has specialized in generators for years before entering the solar industry, so its gas generators make great add-ons to your battery options. The PWRManager also lets you maintain total control over your off-grid system to conserve power for where you need it most.
The biggest downside to the Generac PWRCell, in our opinion, is that the maximum capacity with batteries in series is just 36 kWh. That means you won’t be able to last too long off-grid, even if you max out the capacity.
The other downside to the PWRCell is the DoD, sitting at just 84%. This is below the industry average of 90%, which means you’re paying for capacity you ultimately can’t use to power your home.
Read our full review of Generac for more information.
Generac has just one option available right now, which is the PWRCell. The company’s sole battery has an above-average capacity of up to 18 kWh if you opt for the larger battery. It also comes in a smaller size of just 9 kWh. The performance specs, including the continuous output of 8 kWh, make it a great option for homes with a high energy demand.
We’ll include some information on this battery in the table below for easy comparison to other brands on this list.
|Solar Energy Storage (Per Battery)||9–18 kWh|
|Total Capacity (In Series)||36 kWh|
|Cost Per kWh||$1,100|
|Continuous Power Output||8 kWh|
|Peak Power Output||10 kWh|
Generac’s warranty is right around average for the solar battery industry. It protects the product and battery efficiency for 10 years and guarantees a remaining efficiency of 70% at the end of the warranty term.
Generac partners with a huge number of certified installers to keep its products widely available across the country. Most solar customers in the U.S. should have no problem finding a local installer that carries Generac products. However, it is less prevalent in the industry than some other top options, including the Powerwall and SunPower’s battery, which we’ll discuss next.
|Average Cost ($-$$$$$)|
LG has been developing solar batteries for years, and since it exited the solar panel manufacturing industry, it’s now an even more trusted name for batteries. LG batteries come in a wide range of sizes, meaning it’s easy to customize your solar storage solution based on your energy needs and expectations in blackout conditions.
We recommend the LG battery for anyone who just wants emergency backup power and doesn’t need to maximize their storage capacity.
LG offers three lines of solar batteries in different sizes and power outputs, allowing solar customers to customize their storage systems based on their individual needs.
The performance specifications of the LG batteries are quite good, and most are above average. That includes a high round-trip efficiency rating of 94.5% and power output ratings of 5 kWh and 7 kWh (continuous and peak, respectively).
The LG batteries don’t do well set up in series, so they’re not a great option for solar customers who want high capacities for total peace of mind through power outages. However, the price per kWh is low, and the minimum battery size is well below average for those looking for emergency power only.
The biggest drawback to the LG batteries, in our opinion, is the efficiency loss you’ll experience over time. The warranty coverage is for the standard 10 years, but only 60% of your original battery capacity is guaranteed to remain at that time, so these batteries lose efficiency more rapidly than most other options.
Additionally, the maximum capacity you can have in series is only 19.6 kWh. That may not be enough for some homes to remain off-grid for long, even with an islanding inverter that allows your panels to recharge your batteries.
Read our full review of LG for more information.
One upside of going with LG for your battery storage system is that it has a few different options available, depending on your capacity and output needs.
The table below provides a quick side-by-side view of the three battery options from LG.
|LG RESU||LG RESU-H||LG RESU Prime|
|Storage Capacity (Per Battery)||6.5–13 kWh||6.5–9.8 kWh||10–16 kWh|
|Total Capacity (In Series)||26 kWh||19.6 kWh||32 kWh|
|Cost Per kWh||$1,020||$1,020||$1,020|
|Continuous Power Output||3.0–5.0 kWh||3.5–5.0 kWh||5.0–7.0 kWh|
|Peak Power Output||3.5–7.0 kWh||5.0–7.0 kWh||7.0–11.0 kWh|
LG’s battery warranty lasts for 10 years, which is average. Unfortunately, it only guarantees that your batteries will retain 60% of their original efficiency, which is below the industry standard of 73%.
LG is another manufacturer that patterns with a wide range of installers. Its network isn’t as large as what you’ll find from Tesla or SunPower, but most residents should be able to find a provider that carries LG products and is certified to install them.
Additionally, LG RESU batteries can be installed even if you don’t have solar modules on your roof, so these batteries can be used like traditional electric generators.
|Average Cost ($-$$$$$)|
|Solar Panels, Solar Batteries|
A lot of solar customers choose the Tesla Powerwall just because it’s the product they’ve heard about most often, and others may get shoehorned into a specific battery based on what their installer carries. We recommend choosing your battery carefully, even if it means installing panels with a different solar company.
Below are three things we’d specifically look for in a solar battery, along with a brief explanation as to why we think each is so important.
The solar battery manufacturer you opt for can determine the warranty you get with your equipment, the customer service you’ll experience in the event of a warranty claim, the overall quality and reliability of the battery and more.
Based on the company’s reputation alone, we’d recommend Tesla and SunPower. Tesla is well-known for providing advanced technology, and SunPower is one of the most trusted and reputable companies in the solar industry.
The table below includes a look at how these companies and the ones we’ve reviewed above compare to one another. Keep in mind that these scores are determined using average numbers for each specification we consider if the provider offers more than one battery option.
|Capacity (Out of 20)||20.0||20.0||15.0||15.0||5.0|
|Price (Out of 20)||18.0||15.0||18.0||15.0||15.0|
|Power & Performance (Out of 25)||23.0||23.0||20.0||21.0||21.0|
|Warranty (Out of 20)||15.0||14.0||13.0||13.0||14.0|
|Availability (Out of 10)||5.0||8.0||8.0||7.0||8.0|
|Battery Type & Sustainability (Out of 5)||3.0||3.0||3.0||3.0||5.0|
|Total Score (Out of 100)||84.0||82.0||77.0||73.0||69.0|
In addition to considering the manufacturer of your solar battery, it’s, of course, important to compare the batteries themselves to make sure you get one that meets your needs. Overall, our top recommendations are the Tesla Powerwall+ and the Panasonic EverVolt. The table below includes a comparison of these batteries and the other options we’ve reviewed above.
|Tesla Powerwall +||Panasonic EverVolt||SunPower SunVault||Generac PWRCell||LG Chem RESU 10-HR|
|Per Battery Capacity||13.5 kWh||17.5 kWh||13–52 kWh||9–18 kWh||10.5 kWh|
|Total Capacity Possible in Series||135 kWh||102 kWh||52 kWh||36 kWh||19.6 kWh|
|Price Per Battery||$11,500||$15,000||$12,000||$10,000||$10,000|
|Price Per kWh||$851||$857||$923||$1,100||$1,020|
|Continuous Power Output||5.0 kWh||9.6 kWh||6.8 kWh||8.0 kWh||5.0 kWh|
|Peak Power Output||7.0 kWh||12.0 kWh||10.0 kWh||10.0 kWh||7.0 kWh|
|Depth of Discharge (% Usable Capacity)||100%||100%||N/A||84%||90%|
|Warranty Length||10 years||10 years||10 years||10 years||10 years|
|Efficiency Remaining At End of Warranty||70%||60%||70%||70%||60%|
|Lead Time Issues||Yes||No||No||No||No|
|Available for DIY Installation||No||No||No||Yes||No|
|Available Without Panels||Yes||Yes||Yes||No||Yes|
Looking at the battery specifications we’ve mentioned above can quickly get confusing. Not only are there a bunch of specs that vary pretty widely, but it’s also not apparent what each of them even means. Below, we’ll clarify what some of the less obvious specifications above mean and why we feel each is an important consideration.
Solar batteries are expensive and can often double your solar installation costs if you want full backup capabilities for your home. As such, many solar customers wonder if solar batteries are worth it. Below are a few of the most significant benefits they provide:
We’ll explain each of these benefits in the following sections.
The most obvious benefit you’ll see from your solar batteries is the backup power they provide during blackouts. Having a solar battery or series of batteries installed gives you peace of mind that you’ll be able to maintain emergency power—for things like refrigerators, freezers and medical equipment—no matter what happens.
PV batteries are especially beneficial in areas where extreme weather is common. If you live in a state where hurricanes, tropical storms, tornadoes or other severe conditions frequently lead to blackouts, a backup power option that you can charge for free with your panels is a must-have.
The biggest benefit to having solar panels for many solar customers is the savings on energy bills, but panels can’t always offset your electricity consumption. Panels see reduced or eliminated production on cloudy days and at night, which means you’ll have to pay the retail rate for any consumption at that time, provided you don’t have access to net energy metering.
Solar batteries provide effective NEM since you can store energy for later use if your panel production ever drops below your energy demands. Batteries can save thousands of dollars over their lifetime, especially if your state or utility company doesn’t offer net energy metering and you live in an area with above-average electricity rates.
Since solar batteries provide effective NEM, they can often mean total energy independence if you also have panels installed.
That not only means that you don’t have to rely on a utility provider to deliver electricity, but, more importantly, that you don’t have to deal with increasing energy prices. Electricity costs in the U.S. have increased nearly 10% over the last year alone, according to the Bureau of Labor Statistics (BLS).
Energy prices are expected to continue to go up in the future, too. Your batteries will save you even more than expected because they offset energy consumption for which you would otherwise pay increasing prices.
Another huge benefit of going solar is reducing your carbon footprint since most energy producers rely heavily on burning fossil fuels to generate the power they distribute. If you just have solar panels installed, your consumption on cloudy days, at night or during times of high demand will still rely on fossil fuels.
When you install a solar battery system, you’re far more likely to become totally independent from your power company. That means you’re contributing less to fossil fuel consumption and pollution, and you’re further reducing your CO2 emissions.
Finally, installing panels alone is estimated to boost your home value by around 4.1%. This is substantial, but most buyers are likely to see the increased benefits of your home being equipped with backup power as well. That will likely lead to buyers being willing to pay even higher prices for your property.
Solar batteries work just like other lithium batteries, except they get recharged most of the time with energy from your solar panels.
In a DC-coupled battery, the DC power coming from your panels creates a chemical reaction inside the battery, causing the lithium ions to release electrons. In an AC-coupled battery, the DC solar energy is converted in an inverter to AC power, and then excess energy is converted back to DC in another inverter. When the battery is called on for power, the energy is inverted a third time to AC power to be used in the home.
Generally speaking, DC-coupled batteries are more efficient than AC-coupled batteries because the energy only needs to be converted once, as opposed to three times. This reduces the amount of electricity lost in conversion.
Those free electrons then travel back and forth between the positive cathode and negative anode, depending on which direction energy is moving. The chemical reaction inside the battery is how those free electrons get stored for later use.
There are four different kinds of solar batteries available for residential use:
We’ll explain the differences between each of these below.
Lithium-ion is the most prominent battery technology in the industry. You’ll often see these batteries listed as “lithium iron phosphate” batteries, LFP or LiFePO 4.
LFP batteries boast the highest battery capacities and have the longest-lasting battery lifespan of all of the options. They also require virtually no maintenance. These are best for solar customers looking for high performance, durability and longevity.
LFP batteries are more expensive than most other types of solar storage systems, which is the biggest downside.
Flow batteries are a newer technology being used in the industry. They contain an electrolyte liquid that flows back and forth between storage tanks, which causes a similar reduction-oxidation (redox) process that you see in a lithium-ion battery. Flow batteries are also maintenance-free, and they come with the lowest risk of fire.
Flow batteries all have a 100% DoD, so you don’t lose any of the battery’s nominal capacity. They’re also some of the most durable options available.
However, they’re currently the most expensive since they’re an emerging technology, and the physical size of the battery needs to be large to reach the capacity and power output of lithium-ion batteries.
At this point, we only recommend flow batteries for solar customers who only want emergency backup power and are looking for a long battery lifespan.
Lead-acid batteries are deep cycle batteries that are the most affordable option, primarily because they’ve been around the longest, so the production process is dialed in. The materials are also more affordable than lithium.
Lead-acid batteries are reliable and affordable, but they have a low DoD and a shorter battery lifespan than most other options. They also need regular maintenance and have some installation restrictions due to the potential for leaking.
We recommend these batteries for solar customers who are looking to keep upfront costs to a minimum.
Nickel-cadmium batteries are less prevalent than they used to be because cadmium is a toxic element. Most solar battery manufacturers have abandoned this technology in favor of lithium-ion.
Still, Ni-Cd batteries have excellent durability and are the best suited to operate in extreme temperatures. We recommend staying away from these unless you have no other option based on the climate where you live.
Nickel-manganese-cobalt (NMC) batteries also exist, but the manganese is also toxic, so these are also not prevalent in the industry.
There isn’t one single battery that will be best for every solar customer. We suggest you consider a few different performance specifications when choosing a battery, including the per-battery and total capacity, the price per kWh, the power output, the warranty coverage and more.
Our top recommendation is the Tesla Powerwall +, which we believe lives up to the hype. This is the most popular solar battery, though, and it might be overpowered for your home, depending on your expectations.
As such, we recommend getting a few different quotes that include an array of solar battery options to make sure you’re getting the one that’s best suited for you. You can use the tool below to get multiple free solar battery quotes from providers in your area.
We looked at every major solar battery available in the industry and compared them all based on six main categories and 17 individual metrics. We then weighted each spec, keeping in mind how impactful it would be to your experience. We’ll explain our six rating categories below.
Below, we’ll answer some of the questions we see most often about solar batteries and their specifications.
In our opinion, Tesla manufactures some of the best solar batteries in the industry. The Powerwall+ boasts some impressive performance specs and technology, and it’s highly affordable on a per-kWh basis. With that being said, it’s not right for everyone. We also recommend looking at batteries from Panasonic, SunPower, Generac and LG.
In our opinion, yes. The Powerwall has impressive power output and capacity ratings that can save you quite a lot of money on your electric bills if you don’t have access to net energy metering. It also provides peace of mind through power outages, as each is equipped with an islanding inverter to keep you fully off-grid while you recharge with your panels during blackouts.
A solar battery backup is a battery that gets installed alongside your panels. It stores solar power for use during outages so that you can maintain electricity. They can also provide power for your home on cloudy days or at night, potentially helping you save money on electricity if you don’t have access to a net energy metering program.
Yes, absolutely. The solar batteries available all differ in capacity, the maximum number of batteries you can connect in parallel, their power output, efficiency, degradation, longevity and more. We recommend the Tesla Powerwall+ for most solar customers, but other options might suit you better, especially if you only need emergency backup power.
Comparing authorized solar partners
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