Want to know how to choose the best solar batteries for energy storage? Homeowners typically look for the best solar panels, but an increasingly important part of installing home energy systems is finding the best solar batteries. After all, what good are solar panels if they only produce when the sun is out and you can’t store any of the extra power to be used at night or when the sun isn’t shining?
Energy storage has long been one of the most prevalent challenges to the large-scale feasibility of solar power, but thanks to advances in solar panel battery bank technology, there are plenty of batteries on the market today that can allow homeowners to take full advantage of their solar production.
In this article, we’ll discuss our five favorite batteries for solar panels in 2022. We’ll also talk about how energy storage works and why it will be paramount in solar installations for decades to come.
5 Best Solar Batteries
- Best Overall: Tesla Powerwall 2
- Most Intelligent: Enphase Encharge
- Most Powerful: Generac PWRcell
- Best Value: LG Chem RESU-10H
- Most Versatile: BYD Battery-Box Premium HV
What Is The Importance of a Solar Panel Battery Bank?
Before getting into the best solar batteries, let’s clarify why energy storage is so important.
How Solar Energy Works
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.
Using a Solar Battery Bank
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.
Best Overall: Tesla Powerwall 2
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.
What We Like:
- While it’s on the pricier end (over ,000), it offers a usable capacity of 13.5 kWh, making it one of the most robust solar batteries you’ll find anywhere. As such, we think you’ll have a hard time finding a better bang for your buck.
- This is a full AC lithium-ion battery system, which means it has an inverter/converter already built in.
- The AC system means it can be very easily retrofitted to any house with an existing solar panel installation.
- Its compact design allows for some of the highest energy density on the market and many solar battery storage options for homeowners.
What We Don’t Like:
- The Powerwall 2 is one of the only batteries on this list that is not modular, meaning, there is only one size available. The only way to get a larger capacity is to purchase multiple Powerwalls.
Most Intelligent: Enphase Encharge
A leader in solar manufacturing, specifically microinverters, Enphase Energy unveiled its solar battery backup system, the Enphase Encharge, in 2019. The Encharge 10 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 Encharge battery sizes are available in increments of 3.5 kW, with the Encharge 10 being the most common option.
What We Like:
- The Encharge system features the Enpower™ smart switch, which automatically toggles between solar, grid, battery or generator power depending on the needs of the home.
- Enabling the direct integration of generators for additional off-grid power makes the Encharge one of the most versatile batteries available on the market.
- If you’re using your battery as backup power for an outage, the Enphase is one of few batteries that can automatically detect a grid outage and switch your home into off-grid mode. For context, the Tesla Powerwall requires a manual switch.
What We Don’t Like:
- The Encharge 10 typically costs around the same amount as a Tesla Powerwall, but with less capacity and a lower power rating.
Most Powerful: Generac PWRcell
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.
What We Like:
- The PWRcell offers the highest capacity and power rating of any of the batteries on this list.
- The Generac PWRcell features a modular design that allows you to expand your storage capacity as your power needs evolve. This flexibility allows you to start out with a 9kWh solar + battery storage system and expand in increments of 3kWh up to 36kWh.
- Smart Management Modules (SMMs) automatically manage power distribution during an outage, ensuring critical loads maintain power.
What We Don’t Like:
- Though the most powerful, the PWRcell is also one of the more expensive batteries on our list.
Best Value: LG Chem RESU-10H
The LG Chem RESU-10H lithium-ion battery was developed in South Korea and now stands as one of the most popular solar batteries in the world. The LG Chem is the battery of choice for many major solar companies, including Sunrun and Vivint.
What We Like:
- It’s sized at 9.8 kWh with 90% usable capacity, making it a real powerhouse.
- The battery cells are layered in a unique pattern that helps prevent failure and maximize long-term reliability.
- Independent testing and consumer reviews routinely tout this as a very consistent, high-quality solar battery.
- It has a 10-year warranty and claims to have a battery life of 4,000 cycles.
What We Don’t Like:
- LG’s warranty only offers a 60% energy retention guarantee over the lifetime of the battery, which is a step down from some of its competitors (Tesla and Enphase offer 70%).
Most Versatile: BYD Battery-Box Premium HV
BYD is a Chinese solar company, and its premium battery is one of the best we’ve seen for solar power storage, specifically larger-scale residential or commercial solar applications. BYD batteries are known for their high power and flexibility.
What We Like:
- This modular tower battery is available at a number of different voltage levels so that you can choose the option best suited for your home or business’ energy needs.
- It’s a cobalt-free lithium iron phosphate battery, which performs well at high temperatures and has a longer cycle life than other lithium batteries.
- Battery modules can be stacked in order to increase the total capacity that’s available to you.
- The BYD battery comes with a 10-year warranty and claims to be good for around 3,000 total cycles.
- BYD batteries have some of the best continuous power ratings, meaning despite their capacity, they can provide a great deal of power.
How To Choose the Best Solar Battery Bank for Your Home?
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:
- Peak power refers to the maximum amount of power that can be provided at any one time
- Continuous power refers to the power that the battery can provide over a duration of time. We find the continuous power rating to be the more important figure.
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.
Depth of Discharge
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%.
Price and Warranty
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.
What Are The Different Types of Solar Batteries?
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-ion 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-ion 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.
Final Thoughts: Solar Batteries
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.
FAQ: Best Batteries for Solar Panels
How long do most solar batteries last?
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.
How can I extend the lifespan of my battery?
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.
How many solar batteries do I need?
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.
How do I install a solar battery?
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.
The solar battery is a type of battery that keeps a panel operating even when the sun is not present. So I hope you’ll be able to know how they work and how to choose them from different sources. If there’s anything you would like to know more about, say that I’m not sure, and I will do my best to answer you quickly enough. See you in the next post with something else new and amazing.