What Are the Best Solar Batteries for Energy Storage? (2021)

What are the Best Batteries for Solar Panels?
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By installing solar panels, you can cut your monthly utility bills while also minimizing your environmental footprint. An essential part of setting up your system is finding the best solar batteries to store your power for use even when the sun isn't shining.

Your home's exposure to the sun's rays is one factor that will determine the success of your solar power system. Additionally, an effective solar system requires the right panels, connected to the right battery.

Homeowners typically look for the best solar panels, but your battery is just as important. As such, it's worth asking: What are the best solar batteries for use in your home?

Importance of a Solar Panel Battery Bank

Before assessing the best solar batteries, it's important to clarify what makes batteries so significant.

How Solar Energy Storage Works

When you make the decision to go solar, you'll have a series of solar panels installed on your roof. How solar panels work is that they collect energy from the sun and turn it into electricity. This electricity then passes through an inverter, which turns that raw electricity into a type of current that you can use to power your home.

Most home solar panel systems are connected to local power grid systems, which means that, if you ever produce more solar energy than your home needs, the excess is fed back into the grid. This typically results in a credit from your utility company. By contrast, if your solar system does not produce enough energy, you'll draw energy from the grid.

Using a Solar Battery Bank

So where do batteries come into play? A solar battery bank will store energy that's produced by your system, allowing you to use it later. So, if your system is creating a surplus of electrical energy, you can store it rather than feeding it back into the grid. Later, when your unit is not producing any energy (for instance, when after dark or on cloudy days), you can tap into those energy reserves in your solar battery bank.

The upshot is that, by having batteries for solar panels, you can have a backup power supply for times when the sun isn't shining or for use during a localized power outage. However, you may want to consider a few of the best solar batteries before making a purchase for your home energy storage system.

5 Best Solar Batteries

As you juggle these different considerations and seek the best solar batteries for your system, here are a few specific products that earn our recommendation.

1) Sungrow SBP4K8

Initially developed by Samsung, the Sungrow SBP4K8 is one of the best lithium-ion batteries for in-home renewable energy systems. A few of its biggest selling points include:

  • With a retail price of roughly $4,000, it's fairly affordable compared to some other types of batteries.
  • Thanks to its compact size and its convenient handles, this solar panel battery bank is easy to install or transport as needed.
  • Cable entry points create a quick and intuitive installation process.
  • It comes with a warranty of about 10 years and claims to offer somewhere around 6,000 cycles

2) BYD Battery-Box Premium HVM

BYD is a Chinese solar company, and its Premium battery is one of the best we've seen for solar power storage. Here are a few things we like about it:

  • This modular tower battery is available at a couple of different voltage levels so that you can choose the option best suited for your home energy needs.
  • It's a cobalt-free lithium iron phosphate battery, which performs well at high temperatures and has a longer cycle life than lithium-ion 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.

3) LG Chem RESU-10

The LG Chem RESU-10 lithium-ion battery was developed in South Korea and now stands as one of the most popular solar batteries in the entire world. Consider just a few of its primary selling points:

  • 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.

4) 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 is one of the best solar batteries, and there are several reasons why:

  • While it's a little pricey ($10,000 or so), 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 it demonstrates a fairly decent 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.

5) Powerplus Energy LiFe

Last but not least is the PowerPlus Energy LiFe battery, a modular lithium unit with much to recommend:

  • This battery uses lithium iron phosphate cells, which are considered to be the most durable of any battery cells in the industry.
  • At $3,500, this is a highly affordable option, especially when you consider its 10-year warranty.
  • It offers 3.3 kWh with 100% usable capacity.

Choosing the Best Solar Batteries

As you consider investing in your own solar system, you'll have a few types of solar panels and battery backup options. Here are a few key things to look for when seeking the best solar batteries for your home.

Battery Capacity

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 stackable, which just means that, by combining multiple batteries, you can pool their collective storage capacity so that you can reserve a higher amount of energy.

Power Rating

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).

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.

Depth of Discharge

Another important consideration is depth of discharge. 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 depth of discharge means you'll be able to utilize more of the battery's total capacity.

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. Different batteries have different costs associated with them, and 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.

FAQ: Best Batteries for Solar Panels

As you seek the very best solar panel battery bank, here are a few final inquiries worth addressing.

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.

See How Much You Can Save on a Residential Solar System

Final Thoughts: Best 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 the best solar batteries 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.

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