Compare 5 Best Flexible Solar Panels (2023 Reviews and Buyer’s Guide)
By Christian Yonkers /
In this article, we’ll cover:
When most homeowners think about converting to solar power, the primary focus is on the rooftop panels and their efficiency rating. However, solar batteries are an increasingly important part of a solar energy system, especially for solar customers who want to store their generated solar power for later use.
Especially in areas where net metering isn’t readily available or offered at the full retail rate for electricity, solar batteries can often pay for themselves and help maximize the savings you see from your panels. They also provide peace of mind that you won’t lose electricity through the growing number of power outages throughout the country.
Most solar customers purchase solar batteries directly through their panel installation company, making batteries an effortless add-on option to boost their system’s value. There are many battery options available, but we’ve narrowed them down to the five best brands, which we’ll review in depth below.
Battery Capacity | Continuous Power Rating | Depth of Discharge (DoD) | Round-Trip Efficiency | Price | |
Tesla Powerwall 2 | 13.5 kW | 5.8 kW | 100% | 90% | $12,000+ |
Enphase IQ | 3.4-10.5 kW | 3.84 kW | 100% | 96% | $5,000- $10,000+ |
Generac PWRcell | 9-18 kW | 3.4-6.7 kW | 84% | 96.50% | $9,000+ |
LG Chem RESU 10H | 9.3 kW | 5 kW | 95% | 94.50% | $9,000 |
BYD Battery-Box HV | 5.1-12.8 kW | 5.1-12.8 kW | 100% | 95% | $4,000+ |
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SunPower designs and installs industry-leading residential solar and storage solutions across all 50 states. With a storied history of innovation dating back to 1985, no other company on this list can match SunPower’s experience and expertise.
SunPower earns its position as the top national installer on our list for a handful of reasons: It installs the most efficient solar technology on the residential market, offers the most expansive service area and backs its installations with a warranty well above the industry standard. All the while, SunPower pioneers sustainability efforts within the industry.
If that weren’t enough, SunPower systems come packaged with products all manufactured in-house by its sister company, Maxeon. This means that your panels, solar cells, inverters, battery and EV chargers are designed to work together and are all covered under the same warranty.
SunPower’s biggest downside? Its high-efficiency panels are considerably more expensive than most of its competitors’ products. However, its powerful panels are workhorses that make up for the initial cost with more backend production (think about this like spending more money for a car that gets more miles per gallon).
EcoWatch Rating |
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Better Business Bureau (BBB) Rating |
Year Founded |
Average Cost ($-$$$$$) |
Solar Services |
Brands of Solar Equipment Offered |
Warranty Coverage |
5 |
A+ |
1985 |
$$$$ |
Solar Panels, Solar Batteries, EV Chargers, System Monitoring |
SunPower Panels |
25-year all-inclusive warranty |
Pros
Cons
ADT Solar sets the industry standard for warranty coverage by including a multifaceted guarantee, making it one of the top installers for homeowners who want added peace of mind.
Its warranty coverage includes all of the following for 25 years:
Though in recent years other solar companies have started to offer similar guarantees, ADT Solar has been at it since 2008, performing over 30,000 installations across the country.
EcoWatch Rating |
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Better Business Bureau (BBB) Rating |
Year Founded |
Average Cost ($-$$$$$) |
Solar Services |
Brands of Solar Equipment Offered |
Warranty Coverage |
4 |
A- |
2008 |
$$$ |
Solar Panels, Solar Batteries, EV Chargers, Energy-Efficiency Upgrades |
Silfab, Panasonic and others depending on location |
25-year all-inclusive warranty |
Pros
Cons
Though Momentum’s service area seems small in comparison to the other names on this list, it restricts its growth intentionally, choosing to operate in states with favorable net metering programs and other effective solar incentives. By doing so, it ensures that customers within its service area are sure to secure a favorable and speedy return on investment (ROI), along with a smooth installation process.
It can also then focus more of its energy on service and quality than competitors with a wider national reach. Momentum offers a wide variety of financing options, virtual consultations and a start-to-finish process that remains in-house, rounding it out as one of the most effective and accessible companies for those who live in its regional coverage area.
EcoWatch Rating |
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Better Business Bureau (BBB) Rating |
Year Founded |
Average Cost ($-$$$$$) |
Solar Services |
Brands of Solar Equipment Offered |
Warranty Coverage |
4.5 |
A+ |
2009 |
$$$ |
Solar Panels, Solar Batteries |
Q Cells, REC, Trina Solar, Jinko Solar, Canadian Solar and others depending on location |
25-year manufacturer and workmanship warranties |
Tesla isn’t just an automotive company; it also produces some of the best-reviewed, most technologically sophisticated solar products on the market today. The Tesla Powerwall 2 sets the standard for the best solar batteries, and there are several reasons why.
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A leader in solar manufacturing, specifically microinverters, Enphase Energy unveiled its solar battery backup system, the Enphase IQ, in 2019. The IQ acts as an all-in-one smart energy hub for your entire home energy system, not just your solar panels. A modular battery system, the IQ battery sizes are available in increments of 3.5 kW, with the IQ being the most common option.
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When it comes to sheer power, look no further than Generac. Generac specializes in generators and backup power, so it’s no surprise the company focuses on a product capable of providing the most backup power relative to its competitors.
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Before getting into the best solar batteries, let’s clarify why energy storage is so important.
When you make the decision to go solar, you’ll have an array of solar panels installed on your roof. If you don’t know how solar panels work, they collect energy from the sun and convert it into an electric current. This direct current (DC) electricity then passes through an inverter which turns it into an alternating current (AC), which is the type of electricity we use in our homes.
Most home solar panel systems are connected to local power grid systems, which means that any excess energy produced by your solar energy system is fed back to the grid. If your utility company has a net metering program, you can receive credits for this excess energy. By contrast, if your solar system does not produce enough energy to power your home at any point, you’ll draw energy from the grid.
So, where do batteries come into play? A solar battery bank is a solar energy storage system that will store energy that’s produced by your system rather than sending it back to the grid, allowing you to use it later. Then, when your unit is not producing any energy (for instance, after dark or on cloudy days), you can tap into those energy reserves in your solar battery bank.
The economics of a solar battery makes perfect sense; the more solar energy stored, the less energy you’ll have to purchase from your utility company. In recent years, however, people have started to realize the importance of solar batteries as backup power during a prolonged power outage. With growing instances of extreme weather exposing the vulnerabilities of our infrastructure, battery options and solar panels are becoming a mainstay for those in outage-prone areas like the Southeast and West Coast.
Below, we’ll take a closer look at our recommendations for solar batteries, but if you’re interested in seeing how much a full solar system would cost for your home — battery included — right away, you can use this tool or fill out the form below to get a free, no-obligation quote from a certified installer near you.
As you consider investing in your own solar system, you’ll have a few types of solar panels and backup batteries to choose from. Here are a few key things to look for when seeking the best solar batteries for your home.
Capacity refers to the total amount of electricity you can store in your battery. It’s typically measured in kilowatt-hours (kWh). Note that most solar batteries are modular (or stackable), which just means that, by combining multiple batteries, you can pool their collective storage capacity so that you can store a higher amount of energy.
In addition to a battery’s capacity, you’ll also want to take a look at its power rating. This tells you how much electricity the battery can provide at any given moment, and it’s typically measured in terms of kilowatts (kW). We should note the difference between peak power rating and continuous power rating:
So, how do power and capacity relate? Consider, for instance, a battery with a high capacity but a low power rating. This battery would be able to provide a small amount of electrical power (say, enough for a couple of small appliances) over a long period of time.
A low capacity but high-power battery could produce enough electricity for much more robust appliances, but would only be able to power them for a short span of time after each charging cycle.
Another important consideration is depth of discharge (DoD). This refers to the level of charge the battery must maintain at all times, as dictated by its chemical composition. The rule of thumb here is that a higher DoD means you’ll be able to utilize more of the energy storage system’s total capacity.
A battery’s round-trip efficiency measures the efficiency of the battery bank, or the amount of energy fed into the battery that can then be used.
According to the U.S. Energy Information Association, the industry average round-trip efficiency of solar batteries sits around 80%, meaning that 20% of the energy fed to your battery by your solar panels is lost in the process.
The higher the round-trip efficiency, the better the battery. None of the batteries on our list above have a round-trip efficiency of less than 90%.
Naturally, any time you’re investing in solar equipment, price point is going to be a big concern. Although you may not want to spend much on top of the cost of solar panels, keep in mind that what you’re really after is value and battery costs are only one factor.
Different batteries have different life-cycles and costs associated with them, so paying less money for a less powerful battery may not be the most cost-effective option in the long run.
Closely related to price is warranty. Most batteries for solar panels will guarantee either a certain number of cycles or a set number of years. Warranty is something to weigh against price point, as it can have a major impact on overall value.
As you may have noticed, there are a variety of different types of batteries for solar panels. In this context, type refers mostly to the chemical composition of the battery. Lithium-ion batteries are the most common type, but you may also hear about lead-acid batteries, AGM batteries, gel batteries, deep cycle batteries and more.
The most commonly used batteries for solar panels today are lithium-ion. Advanced lithium-ion technology was developed for electric vehicle (EV) batteries, but the solar industry soon realized the potential it held for home energy storage. Lithium-ion batteries are appealing due to their density, high DoD and long lifespan.
All of the best solar batteries on our list use some form of lithium-ion technology. We should note that lithium iron phosphate batteries are a type of lithium-ion technology.
Lead-acid batteries are what you most likely associate with a common rechargeable battery. This technology has been in use for hundreds of years. Lead-acid batteries offer less than their lithium counterparts due to their low density, shorter lifespan and slow charging. AGM (absorbent glass mat) batteries, sealed lead-acid-batteries, flooded lead-acid batteries and deep cycle batteries are all types of lead-acid batteries.
Flow batteries are an exciting emerging technology that could one day rival lithium batteries. When supplied with energy from solar panels, an electrolyte liquid undergoes a chemical reaction, creating a flow of energy between two separate chambers within the battery. Flow batteries are appealing due to their 100% DoD, relative simplicity and the fact they don’t require as many rare metals.
Flow batteries are currently in development and are still too large for residential applications.
In general, solar batteries can be combined with most solar panels. However, it is important to make sure that the solar battery and solar panel are compatible in terms of voltage and current.
Solar panels produce direct current (DC) electricity, but the voltage and current of the electricity they produce is determined by the size and type of the solar panel. Solar batteries are designed to store DC electricity, so as long as they accept the voltage and current coming from your panels, you shouldn’t have any issues.
To ensure compatibility, we recommend having your batteries installed by a professional solar installer in your area. This will ensure your system components are compatible and that everything is installed properly to maximize efficiency.
The bottom line is that to get the most out of your solar system, you’ll need more than just top-of-the-line panels. Having a reliable solar battery can also be crucial. Make sure you explore your options and account for your home’s specific energy needs when choosing the best solar batteries for your system.
If you want to book a professional solar consultation for free, you can do so by clicking one of the links below. A consultation with a certified company is a great way to find out what type of battery would work best for your home, how much your solar system would cost and how much you can save by taking advantage of local and federal solar incentives.
Our goal in ranking solar batteries here is to equip you with the information you need to decide if a solar battery is right for you and to choose the best one for your budget and energy needs. We’ve ranked batteries based on several weighted factors, which we believe are most important when choosing one. These include:
Since we use the above-weighted factors to rank batteries, none of our ratings are affected by industry partnerships. We’ll explain why we use this methodology in the sections below.
First and foremost, we look at the battery capacity, including the per-unit capacity and the total reachable capacity by combining units. Higher capacities mean a greater chance that the battery will be able to provide power to your home for extended periods of time. This can be helpful for maintaining electricity through outages or inclement weather.
We also consider how modular the batteries are. Some batteries can be placed in series to increase the total available capacity, while others only function as standalone storage options.
Next, we consider the power rating, which determines how much power the battery can provide and over what time period it can provide it.
Batteries that have a high power rating are more suitable for power homes, as they can supply sufficient power for things like major appliances and heating equipment and maintain power for less demanding things, like lights and small electronics.
Price will always be an important factor when converting to solar, especially since your batteries will usually be coupled with a solar array that totals between $15,000 and $25,000. Batteries that are more affordable get ranked a bit higher, but we also consider the value you get for the money.
Next, we consider the warranty coverage included with your battery. As an expensive and integral part of your solar system, you want to make sure that your batteries at least have the industry-standard warranty coverage: 10 years for the equipment.
We give higher scores in this category to batteries that also include performance warranty coverage, like the Tesla Powerwall II and the LG Chem RESU-10H.
Some solar batteries are only available for purchase and installation through certified installers. For example, you cannot buy a Powerwall II from a retailer and install it yourself. Although we strongly recommend having a certified company install your batteries, this does raise the barrier to entry into home solar storage.
Finally, we consider the battery type. As mentioned above, lithium-ion and flow batteries are the best options available for solar storage.
We rank lithium-ion batteries the highest, as they are currently the most widespread and efficient option available. We rank flow batteries second highest, since they are a promising technology. Lead-acid batteries are the least efficient and durable for home storage, so these get ranked lowest in this category.
As you seek the very best solar panel battery bank, here are a few final inquiries worth addressing.
Technically, no; but it is recommended.
As solar panels harvest solar energy, your system then channels electricity to your battery and charges the battery bank. The larger the battery bank, the more power you will have from your battery backup when solar energy is unavailable.
Growing instances of extreme weather have exposed our fragile infrastructures, highlighting the importance of developing reliable sources of backup power. As power outages also increase in frequency, solar energy storage systems are becoming a mainstay for those in outage-prone areas like the Southeast and West Coast. Some public utility companies even incentivize their customers to install solar batteries.
The typical solar battery lasts between five and 15 years. What this means is that you’ll need to replace your battery at least once during the long life of your solar panels, which tend to hold up for 25 to 30 years.
One way to extend the life of your solar battery is to protect it from extreme temperature drops. This means getting a battery with built-in temperature moderation (the Tesla battery is an excellent example) or ensuring earth-sheltered enclosures for your solar panel battery bank.
The number of batteries required can vary from home to home, based on the energy needs as well as the capacity of each battery. (Generally, higher capacity means you’ll need fewer total batteries.) A solar installer can supply a more individualized assessment.
Many — but not all — of the top solar companies include battery setup with solar panel installation. When you buy solar panels, ask your installer about battery add-ons. If you want to retrofit your current system with new battery technology or if you have DIY solar panels, you can hire a separate company to install batteries or look up your specific solar system to figure out how to do it yourself.
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