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Going Green: Solar Batteries

Solar Battery Systems: Advantages, Applications, and Installation

Key Details

  • A solar battery is a device that stores energy generated from the sun
  • Solar batteries are characterized by low internal resistance, low maintenance requirements, and the ability to withstand hot temperatures.
  • The U.S. Energy Information Administration reports an industry-average round-trip efficiency of 80% for solar batteries.
  • Depending on type and capacity, solar batteries cost between $4,000 - $20,000.
  • The best solar batteries come with warranties that typically cover problems traceable to manufacturer materials or workmanship

What is a Solar Battery?

A solar battery is a device that stores energy generated from the sun. Solar batteries differ from other types because they are specially designed to charge optimally using minimal solar power. Some common characteristics of solar batteries include low internal resistance, low maintenance requirements, and the ability to withstand hot temperatures.

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How Do Batteries Work With Solar?

The average solar energy storage system functions in the following order:

  1. Solar panels draw energy from the sun and convert it to electricity.
  2. The direct current (DC) generated passes through an inverter system that converts the DC to alternating current (AC).
  3. The AC then flows from the inverter and powers the home, office, or other structure.
  4. As this process continues, the building immediately uses some of the current while the battery collects and saves the unused electricity.
  5. When direct solar energy is no longer available, the system powers the house with energy stored in the battery until the sun comes out again and the process restarts.

Note: Batteries that store power received from solar panels are called solar batteries, regardless of type or design.

According to the U.S. Energy Information Adminstration, the industry average round-trip efficiency of solar batteries sits around 80%.

The higher the round-trip efficiency, the more energy you get to utilize from the battery. So, if you utilize a lot of energy, you may target batteries that have higher round-trip efficiency.

What is the Average Cost of Solar Batteries?

The cost of solar batteries can vary widely depending on factors such as the type and capacity of the battery, the brand, and the installation cost.

Small-capacity batteries cost between $4,000 to $8,000. Large-capacity batteries, on the other hand, cost between $10,000 to $20,000. Solar batteries also qualify for government loan financing programs or energy incentives like the Federal Solar Tax Credit, which helps reduce the ownership cost.

Estimated Cost of Popular Solar Battery Brands

Solar Battery Brand Price Range ($)
Tesla PowerWall 2 $12,000 - $14,000
Sonnen Eco $6,000 -$ 9,000
Enphase IQ $3,000 - $10,000
Enphase IQ 10 $18,000 - $20,000
Generac PWRcell $3,000 - $8,000
LG Chem Res 10H $8,000 - $11,000

Note: The availability, eligibility criteria, and specifics of government incentives can vary. Check with local government agencies, utility companies, or consult with a solar energy professional to understand the incentives applicable to solar batteries in your specific location.

Choosing a Solar Battery

What is the Best Solar Battery on the Market in the US?

There is no singular “best solar battery” in the market. The option that’s best for you depends on the requirements of your solar panel and what you intend to use the battery for.

Note: Experts recommend that homeowners research and compare different options based on specific requirements, energy needs, and budget before making a decision.

Buyers have the choice of different solar brandsin the United States, ranging from large multinational corporations to smaller, locally-based companies. Some of the most well-known solar brands in the U.S. include:

Tesla Powerwall: The Tesla Powerwall is one of the most recognized solar battery brands. Tesla offers various models, including the Powerwall 2 and the Powerwall+. These batteries are known for their sleek design, high energy capacity, and integration with Tesla's energy management system.

LG Chem RESU: LG RESU (Residential Energy Storage Unit) is a line of solar batteries. The LG Chem RESU models, such as the RESU10H and RESU16H, are known for their reliability, efficiency, and compact size.

Sonnen: A manufacturer of solar batteries, Sonnen offers models like Sonnen eco and Sonnen ecoLinx. Their batteries are designed for intelligent energy management, with features like smart charging, time-of-use optimization, and backup power capabilities.

Enphase Ensemble: Enphase Energy, known for their microinverter technology, also offers solar battery solutions. The Enphase Ensemble line includes models such as the Ensemble AC Battery and the Ensemble Encharge.

BYD B-Box: BYD (Build Your Dreams) is a Chinese company that produces solar batteries, including the popular B-Box line. The BYD B-Box batteries come in different capacities and are known for their high energy density, longevity, and scalability.

Generac PWRcell: The Generac PWRcell is a modular solar battery system designed for both residential and commercial applications. It offers scalable storage options and can be customized to meet different energy needs

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Top Solar Battery Brands in the U.S

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Are Battery and Energy Storage Systems the Same Thing?

Energy storage systems are more complex than batteries. These advanced storage systems comprise several parts, including intelligent software, computerized control systems, and specially-designed batteries.

Solar storage systems use software algorithms to manage energy production, storage, and eventual disbursement when necessary. An energy storage system may be a small-scale setup with intelligent software and solar batteries for home, or a large setup for use by a large corporation, factory, or a small community.

Are Batteries a Critical Component for Clean Energy?

Batteries are essential to providing clean energy, whether on a small or large scale. One central argument against heavy reliance on clean or renewable energy is intermittency. While experts believe that clean energy is safer and more cost-effective, it is nearly impossible to ensure a constant supply of electricity generated from renewable sources without a storage unit.

Note: Experts advise that homeowners use reliable batteries to store electricity generated from wind or solar energy for distribution during periods where energy from these sources is unavailable.

Batteries also solve the base load energy problem. Base load energy is the minimum power capacity an energy source can produce and supply to meet a power grid's minimum requirement without interruption. Before now, achieving base load energy required fossil fuel plants (natural gas, nuclear, coal, etc.) to burn fuel consistently.

However, batteries can provide the required base load energy by storing energy without burning or consuming any extra materials. Consequently, power systems focused on clean energy must use batteries to store energy from natural sources for later disbursement.

Will a Solar Battery Save Me Money?

Yes. A solar battery is easily the best way to save money and ensure an uninterrupted power supply. Although the initial cost of installing a solar energy system might be high, it is usually cheaper than drawing power from your local electricity grid. Instead of permanently relying on the local grid, solar batteries can provide energy by drawing power from solar panels and saving the energy until when needed.

Some solar systems operate a hybrid structure where batteries charge via solar energy or the local power grid. Either way, using a solar battery will help you save money in the long run because your electricity bill reduces when you are not entirely dependent on the grid.

How Many Batteries Will I Need?

The number of batteries you'll need depends on your energy usage. Your required amount of energy is measured in kilowatt-hours (kWh) over a specified period. For instance, if you use 1,000 watts for 15 hours daily, your backup energy system should deliver 15 kWh each day. This calculation would help you decide exactly how many batteries you need to install.

If you don't buy enough batteries, you risk running out of power and must find another alternative, like a fuel generator. On the other hand, buying too many batteries unnecessarily increases the purchase cost and adds to maintenance requirements.

What are the Different Ways of Connecting Batteries to a Solar Array?

You can connect batteries to a solar array in series or parallel. The decision on which one to use depends on your desired target output voltage and system capacity.


Batteries connected in series have the same current flowing through the circuit's components. The batteries are connected in a line, with one battery's positive end connected to the other's negative. The advantage to a series connection is a corresponding increase in the overall available voltage.

For instance, you can achieve an 18-volt battery system if you connect three 6-volt batteries in series. The downside is that since the series method is a straight-line connection, a breakdown in one component will affect the entire circuit.


Instead of connecting in a straight line, the required arrangement for the parallel method is to connect all positive terminals together and do the same for the negative terminals. A major difference between the series and parallel methods is that the voltage remains the same when batteries are connected using the parallel method. However, a parallel connection ensures that the current capacity is higher. Also, if one battery stops working, others will continue their normal function.

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Battery Installation

Efficient Solar Battery Systems: Installation Tips and Best Practices

How Much Space Will I Need for My Batteries?

The amount of space you need for battery installation depends on your daily energy usage, your battery type, and how long you want your energy system to run without a recharge. For instance, if you need 24kWh for 2 days using lead acid batteries, you need a total of 2,000 amp hours (AH) at 12 volts.

This means that your home or office must have enough space for 8 batteries if each one is 250AH. Also, lead acid batteries may take up more space than lithium-ion batteries because the former is less energy dense. In addition to the required physical space, where you install your batteries also matters.

Where Will They Be Installed?

The type of battery you choose will determine the appropriate location. For instance, lead acid batteries function optimally between 50°F and 80°F. Although they can operate outside this range, their efficiency and lifespan might be reduced.

Also, flooded lead-acid batteries may require periodic liquid electrolyte refills. The process comes with certain risks, including acid contact and fume inhalation. Consequently, some experts recommend a location some distance from the living area, such as a garage or outdoor shed.

On the other hand, Lithium solar batteries have a broader temperature range of between 32°F and 100°F and are much more energy dense than lead acid batteries. These batteries are also preferably installed indoors, even though manufacturers have designed products and systems where outdoor installation is possible. However, it might be necessary to install batteries indoors for better efficiency if your home is in an area prone to extreme temperatures.

Sodium-sulfur batteries are a completely different ball game. Probably the most important thing with this type of battery is to install them where you can supply the units with the heat they require to function.

How Much Space Will I Need in My Home?

The amount of space you need to install an energy backup system, including solar batteries for home, depends on your energy usage. People who need completely off-grid solar system packages with batteries will require a much larger space to accommodate all of the system's components, including solar panels, batteries, buffers, and other items. However, if you operate a hybrid power system and you're not always hooked on solar batteries, then you'll need a lot less space. Before installing a backup system, ensure that you have enough space to accommodate the setup that will satisfy your energy requirements.

What’s a Smart Inverter and Do I Need One?

A smart inverter supports energy grid function by automatically regulating voltage and providing frequency support when there is reduced frequency. Smart inverters also have “ride-through” capability, which ensures that power remains on when there is a disruption in frequency or voltage.

A smart inverter is necessary because it does more than simply convert direct current to alternating current. Its ride-through and frequency support functions help the system adjust whenever an inconsistency or downtime occurs. This considerably trumps standard inverters that are mostly only useful in static or predictable situations. Also, if your utility allows you a rate structure, some smart inverters can be programmed to store more power when rates are favorable.

Do Batteries Come With Warranties in the US?

Buyers enjoy warranties on batteries purchased in the US. However, you should note the specified warranty period may vary between manufacturers and battery types. Also, battery warranty is usually limited. This means the warranty may cover specific faults and not others.

In most cases, the warranty will cover all problems traceable to the manufacturer's materials or workmanship. Other faults caused by factors such as overcharging, physical damage, wear and tear, or incorrect application, are usually not covered by the manufacturer's warranty.

Do I Need to Update My Home Insurance?

You should update your home insurance after installing an energy storage system. Most home insurance plans cover the house and all valuables up to a point specified in the insurance.

If you want to protect your investment in the energy system, it's important to update your insurance to reflect the additions. If you decide to remove the system for any reason, updating your home insurance might also be important to reduce the payable premium.

Will I Need a Permit to Install a Battery?

Solar system installations in the US require permits. Since the process involves a lot of electrical work, state law requires that licensed professionals do the installation. In addition to this, you need to obtain building and electrical permits before commencing installation.

You may also need an interconnection approval to connect your solar energy system to the local electricity grid. This approval is necessary for net metering and allows you to offset your electricity bills by sending excess power to the grid. A professional solar company can handle the permit process along with the installation.

Note: Depending on the town or city in the US, obtaining the necessary permits may take up to 40 days.

How Do I Select a Qualified Installer?

After deciding on the needed capacity and battery types, you need to ensure that a qualified professional handles the installation process from start to finish. The following are a few things to consider before selecting an installer.

Experience and Expertise

Choose installers with the credibility, expertise, and experience needed for the installation. If you can find online reviews, check them thoroughly to see if anything curious stands out. If you can't find reviews, ask the installer clear questions about how much experience they have, warranty specifics, information about modules, capacity and installation details, and solar incentives, if any.


Installers should be appropriately licensed and recognized by local authorities in your town or city. If the company uses subcontractors, you should also verify their credentials. Remember that a valid license is valid for all involved parties.

Home Visit

Experienced installers know that it is sometimes difficult to conclude capacity and installation until they have visited the proposed installation site. In most cases, specifics about connection type, battery type, system capacity, and the required number of solar panels are only calculable after a home visit.


The entire process should be transparent enough for you to understand, even if you have no experience. The installers should also be able to answer your questions and break down all processes into easily understandable bits. If your installer is withholding information, they may not be as qualified as you'd prefer.

No Sales Tactics

Avoid installers who quickly apply sales tactics to get you to decide quickly. Experienced installers are usually not in a rush even though they want to turn a profit. Professionals talk you through specifics of the energy system, try to get an idea of your energy needs, and are willing to visit your home before getting you to commit. If you're experiencing undue pressure, you should probably find another installer.


If you're unsure about what installer to use, you can start by talking to friends, family members, or neighbors who have purchased and installed energy storage systems. Firstly, this would give you some confidence, especially since someone you know has used this company or installer and can vouch for them. Secondly, even if you don't use your neighbor or friend's recommended installer, talking to others can give you an idea of what to expect. This might make walking away from a fraudulent or inexperienced installer a bit easier.


Installers will provide you with varying quotes for the same job. Doing your research for some idea of current prices may help you filter installers easier. You should probably walk away if the price is much higher or lower than your research states.

Workmanship Warranty

It's never enough to only know the duration of your warranty. It is also essential to understand what type of warranty you're getting and all related specifics. Your installer should be able to explain what kind of damage the warranty covers and for how long. You should also know who to call to take advantage of the warranty if the need ever arises.

After-Sales Service

Look for installers that offer after-sales service, especially operational guidance in the first few weeks of use. Any installer unwilling to help after the installation might not be worth your time or money.

What Should Be Included in My Battery Backup Proposal?

Although specifics may vary, the average battery backup proposal should contain more than enough information about the system to be installed. Regardless of individual home specifics, a complete proposal should include the following:

  • Total cost of the system, including the cost of each equipment and required installation
  • Specific details of each equipment, including
    • Battery size, model, and manufacturer
    • Battery management system if necessary
    • Number of batteries
    • Solar panel quantity and specifications
    • Inverter manufacturer and model
  • All applicable warranties, including inverters, batteries, and workmanship
  • Details of additional installations or materials needed for installation, fitting, or other electrical work
  • Installer information, including contact details and office location

Battery Types

Solar batteries for homes can be categorized based on their type, brand, and quality. There are four major types of solar batteries. These types are as follows:

Lithium-ion Solar Batteries

This is one of the most popular solar battery types, as it has a very high energy capacity. The batteries were originally developed for EVs but were soon adopted by the solar industry because of their high potential for energy storage.

Generally, lithium-ion solar batteries have higher durability than other types of solar batteries. They are also more appealing to solar customers because of their higher DoD and longer lifespan.

Pros of lithium-ion batteries

  • Longer lifespan
  • Require less maintenance
  • Lighter and smaller design when compared to lead-acid batteries.

Lead Acid Batteries

Lead acid batteries are of two different types -sealed lead-acid batteries and flooded lead-acid batteries. This type of solar battery has a shorter life span compared to other types of solar batteries. A lead acid battery can last for a maximum of 3 to 5 years. Their DoD is also shorter when compared to other solar batteries.

However, lead-acid batteries make up for their deficiencies in their pricing. These types of batteries are cheap and affordable for homeowners who do not need higher energy capacity. Due to the relatively cheap cost of procuring a lead-acid battery, it requires a higher level of maintenance.

Pros of lead-acid batteries

  • Lead acid batteries are a cheaper solution for homes that do not use a lot of energy.
  • Large current capability.
  • Wide range of sizes and specifications available.

Flow Batteries

Flow batteries are relatively new in the battery technology scene. However, they have great potential and could one day become a close rival to lithium solar batteries. These batteries are attractive to customers due to their 100% DoD, relative simplicity, and the fact that they are more sustainable since they don't require as many rare metals.

Pros of Flow Batteries

  • The battery has 100% DoD
  • The battery is water-based and hence a non-toxic type of battery.

Sodium Nickel Chloride Battery

The Sodium-Nickel battery operates at extreme temperatures, which makes it more popular amongst commercial-scale projects. They have an estimated lifespan of 15 years and an energy capacity of 100 to 200 MAh. However, they are banned in most countries due to their high toxicity.