Everything You Need To Know About Solar Batteries (2023)

Whether you’re new to the world of solar power and searching for the best system for your building or have had your home bedecked with solar panels for years, a solar battery can make a tremendous difference in the efficiency and versatility of your solar setup. Solar batteries store the excess energy generated by your solar panels, which can then be used to power your home during gloomy, rainy days, or after the sun sets.

Our guide to solar batteries can help answer your questions about solar batteries and assist in selecting the best option to meet the needs of your facility or household. But note not all solar installation or sales companies offer solar panels.

What Are Solar Batteries, and How Do They Work?

Without somewhere to send energy produced by your solar panels, solar would be fairly inefficient—your appliances would only work when the sun is shining and your panels are working. If you don’t use the energy, it’d be wasted—and you wouldn’t be able to use it at night. Enter solar batteries, which store energy generated by your panels for use when you actually need it. Solar batteries are an alternative (or addition to) feeding energy back to the grid and can help you make your house or facility somewhat immune from power outages and even help take it off-grid entirely.

Solar Battery Types

The four main types of batteries used in the world of solar power are lead-acid, lithium ion, nickel cadmium and flow batteries.


Lead-acid batteries have been in use for decades and are one of the most common types of battery used in automotive and industrial applications. They have a low energy density (meaning they cannot hold much energy per kg of weight), but remain both cost-effective and reliable and thus have become a common choice for use in a home solar setup.

Lead-acid batteries come in both flooded and sealed varieties and can be classified as either shallow cycle or deep cycle depending on the intended function and safe depth of discharge (DOD). Recent technological advancements have improved the lifespan of these batteries and lead-acid continues to be a viable option for many homeowners.


The technology behind lithium-ion batteries is much newer than that of other battery types. Lithium-ion batteries have a high energy density and offer a smaller, lighter and more efficient option. They allow the user to access more of the energy stored within the battery before needing to be recharged, making them great for use in laptops and phones—and in your home.

The major drawback of lithium-ion batteries is the significantly higher cost to the consumer. If improperly installed lithium-ion batteries also have the potential to catch fire due to an effect called thermal runaway.


Nickel-cadmium batteries are rarely used in residential settings and are most popular in airline and industrial applications due to their high durability and unique ability to function at extreme temperatures. Nickel-cadmium batteries also require relatively low amounts of maintenance when compared to other battery types.

Unfortunately, cadmium is a highly toxic element that, if not disposed of properly, can have a significant negative impact on our environment.


Flow batteries depend on chemical reactions. Energy is reproduced by liquid-containing electrolytes flowing between two chambers within the battery. Though flow batteries offer high efficiency, with a depth of discharge of 100%, they have a low energy density, meaning the tanks containing the electrolyte liquid must be quite large in order to store a significant amount of energy. This size makes them a costly and impractical option for most household use. Flow batteries are much better suited to larger spaces and applications.


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Solar Battery Costs

The cost of a solar battery or battery system will depend on the type and size of the battery chosen. Generally, lead-acid batteries will incur a lower up-front cost to the consumer than lithium-ion batteries, but depending on how the batteries are used, investing in a lithium-ion battery could save money long-term.

A single lead-acid battery can cost between $200 and $800 or even more depending on the size/power of the battery. Multiple lead-acid batteries may be needed to keep a household powered completely. The average cost of a residential lithium-ion solar battery system with installation falls in the $7,000 to $14,000 range.

The prices of nickel-cadmium and flow batteries vary widely and depend on the size and scale of the installation. These batteries are not commonly used in residential dwellings and are better suited to commercial/industrial settings due to cost, durability, size, stability in extreme temperatures and requirements for disposal upon replacement.

Things to Look for When You’re Picking a Solar Battery

Several factors contribute to the performance of your solar battery. Before choosing your battery system, consider the following:

Type or Material

Among the types of batteries to choose from, each type offers a different major advantage. Weighing these pros and cons can help you decide which style is right for you. If you’re looking for something compact and longer-lasting, lithium-ion may be right for you. Lead-acid might be better for those conscious of more immediate budget constraints.

Battery Life

The “lifespan” of any battery is multifaceted; the age, type, quality and depth of discharge of the battery all contribute to its longevity. Referring to the manufacturer’s specifications for a battery can help you determine how long it’s likely to last.

In general, lead-acid batteries can last anywhere from one to 10 years depending on how they’re used. Lithium-ion batteries typically last seven to 15 years.

Depth of Discharge

Depth of discharge refers to how much of a battery’s stored energy is used before the battery is recharged. Typically, the deeper the battery is discharged, the shorter its lifespan will be.
Batteries often come with both a cycle life estimate (indicating how many cycles it will last given a particular depth of discharge) and a recommended maximum depth of discharge.

Both lead-acid batteries and lithium-ion batteries will decay more quickly when deeply discharged, but lead-acid batteries tend to offer a lower tolerance for deep discharges than lithium-ion batteries, significantly reducing life expectancy if deeply discharged on a regular basis.


Solar systems and batteries are not 100% efficient when transferring and storing the collected solar energy from panels to batteries, as some amount of energy is lost in the process. Depending on the amount of energy you’re able to generate from your panels and how your system is configured, it may be worth investing in a more expensive, more efficient battery. This can help save money long-term. Your solar panel efficiency and battery capacities will be calculated and your system explained to you by any competent sales and installation team, but our solar resources can help you understand exactly how your system works, too.


THIS IS AN ADVERTISEMENT AND NOT EDITORIAL CONTENT. Please note that we do receive compensation for any products you buy or sign up to via this advertisement, and that compensation impacts the ranking and placement of any offers listed herein. We do not present information about every offer available. The information and savings numbers depicted above are for demonstration purposes only, and your results may vary.

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How to Select the Best Solar Battery for Your Needs

When selecting a solar battery for your setup, you may want to consider how you’ll use the batteries and what your need actually is, how safe each system might be and the overall cost of the system.

Use and Need Considerations

Do you need the battery or battery bank to provide only short bursts of emergency power when the power goes out, or do you need it to maintain the combined electrical needs of your entire household/facility for extended periods of time? How much sun exposure do you expect to have on a daily basis? Consider the recommended depth of discharge for your batteries and how this will affect their lifespans.

Safety Considerations

How does the battery need to be stored to maintain it safely? What kind of maintenance does the battery require? What is the safe temperature range for your battery and is the storage location going to maintain that temperature? When the time comes, how do you plan to dispose of/recycle the battery?


Does it make more sense for you to spend less up front for lead-acid batteries, or invest in the efficiency and longevity of lithium-ion batteries? How many batteries will you need to purchase to provide for your needs? What’s the expected lifespan of the battery and will you be prepared to replace it when it dies?

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Benefits of Using A Solar Battery

The best thing about solar battery storage is that it lets you store the excess energy you produce. One of the most important benefits of solar batteries is that they don’t just provide backup power; they also produce energy after hours when you don’t want to send excess solar electricity back to your local utility company.

Energy Independence

A solar battery is an essential component of a home reliant entirely on solar power. The battery can store power during the day, so it’s available at night to keep the lights on for an entire evening. A solar battery system can also turn your off-grid solar system into an emergency backup during power outages.

Electric Bill Savings

Solar power batteries can help consumers power their homes by harnessing the sun. This will allow them to purchase less from the grid and save money on their electric bill.

Reduce Carbon Footprint

Solar energy can minimize our use of fossil fuels and protect our environment. Solar batteries generate solar energy when exposed to sunlight, which can then be used to power devices or recharge a laptop or phone battery.

Are Solar Batteries Worth It?

Solar batteries represent a significant upfront financial investment, but can ultimately help save you money on energy costs after sundown or during an emergency. If you’re living off-grid, they may be critical components of your energy system.

Solar batteries provide your home with clean, fairly green, renewable energy that would otherwise need to come from an outside source. Some areas also provide incentives or rebates to help mitigate the costs of adding a solar battery to your system and it’s possible to receive up to 30% off of your battery installation if you qualify for the federal solar tax credit.

Ultimately, only you can decide if the investment in a solar battery and its rewards is worth the cost and upkeep requirements.

Frequently Asked Questions (FAQs)

How long do solar batteries last?

Solar batteries last for about 5 to 15 years. The life of the solar battery depends on its type, how well it’s maintained and how frequently it gets used.

What are the disadvantages of using solar batteries?

Cost: Solar batteries can cost anywhere from several hundred to several thousand dollars to purchase and install. Batteries also offer a limited lifespan and will eventually need to be replaced.

Maintenance: Different batteries maintain different maintenance requirements in order to operate safely. Proper maintenance can be both costly and time-consuming.

Space: Batteries take up space and, depending on the size of your system as well as the type of battery you choose, the amount of space needed to store and adequately ventilate your batteries may be significant.

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Safety: There are inherent risks associated with operating any batteries (overheating, leaking, etc.), especially if products are not installed and maintained properly.

Complexity: Adding batteries to your system will create additional complexity with regard to wiring and setup. Depending on your level of electrical expertise, you may wish to consider consulting or hiring a professional when installing solar batteries.

How many batteries does it take to power a house with solar?

The quantity of batteries you will need depends upon the type of battery, the storage capacity of the battery, the size of your solar system, the energy requirements of the circuits and appliances you wish to power and the amount of time you wish to provide power to your circuits/appliances.

The best way to estimate your energy needs is to figure out the kilowatt-hours you would require in the event of a power outage and compare that to the capabilities and specifications of the batteries and systems you consider.

How long do solar batteries hold charge?

The length of time your solar battery will hold a charge depends on the battery and the amount of energy being stored. A standard solar battery will store energy for one to five days.

What solar batteries are the best?

The best type of battery for one system may not be the best for another. For a home solar system, an adequately sized battery bank of sealed lead-acid batteries or a lithium-ion battery system will likely fit the bill, depending on the intended use (daily, short/long duration, etc.)

Some common brands for solar batteries include: Tesla, Panasonic, LG Chem, Electriq Power, Enphase, Generac, Sunpower, Solar Edge, SunVault and Renogy.

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What do I need to know about solar panel batteries? ›

Solar batteries have a super high cycle life. This means that solar batteries can support a higher number of complete charge/discharge cycles before their capacity falls under 80%. This means that solar batteries don't require frequent maintenance or replacement.

What are 3 drawbacks to storing solar energy in batteries? ›

Disadvantages of A Solar Battery
  • Energy Storage is Expensive. The cost of energy storage is quite high and can quite easily increase the cost of your solar PV system substantially. ...
  • Increased Complexity of Your Solar System. ...
  • Increased Maintenance For Your Solar. ...
  • Lifespan of Home Battery.
May 3, 2018

How many batteries do I need to run a solar panel? ›

If you want to save the most money possible, you'll need enough battery storage to cover your energy usage when your solar panels aren't producing – somewhere around 2-3 batteries. If you want to keep the power on when the grid is down, you'll usually just need one solar battery.

What is the problem with solar batteries? ›

In the short term, one of the biggest challenges with solar power storage is simply that the batteries used for this application are still quite costly, and they are large. The more power you need, the larger your battery will need to be.

What type of solar battery is best? ›

Lithium-ion batteries are considered the best solar battery option for most homeowners. Lithium Nickel Manganese Cobalt Oxide (NMC) and Lithium Iron Phosphate (LFP) are the most common lithium varieties. There are more NMC batteries available since it's an older technology, but LFP options are becoming more popular.

What is the best battery for off-grid solar? ›

Lead acid or gel type batteries may work if you're looking to test a solar setup short-term to see if it's a right fit for you. But when you consider efficiency, reliability and lifetime cost, it's clear that lithium comes out on top as the best contender among all off grid solar batteries.

How do I keep my solar battery healthy? ›

Tips for Maintaining Your Lead Acid Solar Batteries
  1. Limit Battery Count. ...
  2. Rotate Batteries Routinely. ...
  3. Keep Batteries Charged. ...
  4. Use Distilled Water. ...
  5. Ventilate Your Storage. ...
  6. Equalize Your Batteries.
Jul 6, 2019

Do solar batteries work in a blackout? ›

Is your solar battery blackout-proof? Forget candles. Solar batteries can keep the power running during a blackout.

Is it better to have more batteries or more solar panels? ›

By adding battery storage onto your Solar Panel system you will be able to use more of the energy your Solar Panels generate. Resulting in greater savings and less green energy waste. As a solar battery stores energy generated in peak sun-hours, you will have a continuous supply of renewable energy throughout the day.

How many batteries do I need for a 200 amp solar system? ›

Depending on the battery type and capacity, a 200-watt solar panel can charge 100Ah of battery capacity every 2.5 hours. On a sunny summer day with 7.5 hours of direct sunshine, a 200-watt solar panel can charge three 100Ah batteries, two 150Ah batteries, or one 300Ah battery.

How many powerwalls do you need to go off the grid? ›

Another critical factor is whether you want to go off-grid with your solar system and backup batteries or stay grid-tied. If you have a house bigger than 2600 sq ft or above-average energy consumption, consider installing at least 3 Tesla Powerwalls for the whole home backup system.

How many solar panels do I need to run a 1500 watt inverter? ›

The installation of 12 solar panels with a total of 1500 Watt peak.

What causes solar batteries to drain quickly? ›

It may be that charging and discharging the batteries too quickly is a sign of inadequate battery sizing, improper IMEON settings, or the end of battery life.

Do solar panels drain batteries at night? ›

In short, if solar panels are properly set up, it does not drain the batteries at night. They do draw power from them though, because of the lack of sunlight and the need for supplying your appliances or charging your mobile phone which is usually done over the night.

Do solar batteries need maintenance? ›

Most batteries require addition of water every 6 to 12 months. There is no need to fill them more frequently than needed to submerge the plates. Fill them only to the level recommended by the manufacturer, generally about an inch below the top, otherwise they may overflow during finish-charging.

How much is a good solar battery? ›

But as a starting point, the price of solar battery storage starts at $5000 or around $105 a month over 5 years for a smaller Enphase system, while larger batteries such as Tesla Powerwall are around $18,000 fully installed.

What is the safest solar battery? ›

Solar battery safety

The safest one in existence today is lithium iron phosphate battery technology, or LFP. These are highly stable and have no chance of overheating. They also run very cool which means they can be placed inside your home, if desired, and won't require extra ventilation or cooling.

What are the latest for solar batteries? ›

Best solar batteries of 2022
  • Tesla Powerwall.
  • Generac PWRcell.
  • Delta BX6.3.
  • Sonnen ECO.
  • LG RESU.
Dec 16, 2022

How many solar batteries do I need to run a refrigerator? ›

How many solar panels do I need to run a refrigerator? The average refrigerator takes about three or four average solar panels to run. The average refrigerator found in the United States uses approximately 57 kWh per month while the average freezer uses 58 kWh. Adding those together brings a combined total of 115 kWh.

How many batteries and solar do I need to go off-grid? ›

The average off-grid home usually requires about 7 Kw (or 7000 Watts) of power to rely entirely on its own energy production. Solar panels come in various forms, shapes and sizes.

What is the most common type of battery used for solar panels right now? ›


Lithium-based energy storage systems are overwhelmingly the most common storage technology used within the solar market. These batteries are characterized by the transfer of lithium ions between electrodes during charge and discharge reactions.

What kills solar batteries? ›

What causes solar batteries to drain quickly? It may be that charging and discharging the batteries too quickly is a sign of inadequate battery sizing, improper IMEON settings, or the end of battery life.

Should solar batteries be charged to 100%? ›

The battery could be charged up to 100% if the load requires a voltage boost for a short amount of time. Range between 40% and 80% is the most stable range (approximately 0.5 Volt drop). It means that in this range, the battery will slowly discharge and will yield the rated output voltage.

What kind of water do you put in solar batteries? ›

Distilled water should be added into the cells so that no metal lead surfaces are visible. Most batteries will have a "fill line" indicating where the electrolyte level should be. The maximum fluid levelis approximately 1/2" below the cap. Do not overfill your batteries, you don't want them to spill!

How long will a solar battery last during a power outage? ›

“An average homeowner typically will draw 2 kilowatts maximum during an outage, and an average of 750 to 1,000 watts during the course of the outage," he said. "This means a Brightbox will last for 10 to 12 hours, while a Powerwall will last for 12 to 15 hours.”

How do you charge a solar battery without sunlight? ›

Solar panels can charge with other forms of visible light besides sunlight. Artificial lights such as incandescent fluorescent bulbs can be used to charge solar cells, provided the light is strong enough.

Can solar batteries charge without direct sunlight? ›

The short answer is – yes! Although direct sunlight is key to charging solar panels, they continue to charge even on cloudy, overcast days. Sol's innovative lighting systems and products, for example, are designed to work for at least four days with no direct sunlight!

Can a solar battery be too big? ›

An oversized solar battery could also lead to chronic undercharging and poor performance and lifespan. Search tool allows you to specify exactly what elements of a home should be powered by the battery.

Can a solar panel be too big for a battery? ›

If your battery bank is undersized, you may not be able to fully meet your energy needs. If your battery bank is oversized, your solar panels may not be able to fully recharge the batteries, which may lead to chronic undercharging, decreased lifespan, and poor performance.

Does solar battery increase property value? ›

Solar panels could be the best way to increase your property's value, as well as reduce your energy bill. For many people, their home is their biggest asset and maintaining it properly is crucial to ensure it holds its value.

How long will a 200Ah battery run an appliance that requires 400W? ›

You get the result: A 200Ah 12V AGM deep cycle battery will run a 400W device for 4.80 hours (that's 4 hours and 48 minutes). With this calculator, you can estimate running time for pretty much any battery.

How long will a 300w solar panel take to charge a 200Ah battery? ›

As a general rule, a 200Ah lead-acid deep-cycle battery would need a 300 watt solar panel to fully recharge from 50% Depth of Discharge (DOD) assuming 4 peak-sun-hours per day. Charging would be complete in one day with a clear sky.

How many hours can a 200Ah battery last? ›

If you have a 200ah battery, it can supply 20 continuous amps for 10 hours or 10 amps for over 20 hours.

Will a Powerwall run an air conditioner? ›

This includes 120V loads such as lights, plugs and small appliances as well as 240V heavy loads such as air conditioners, electric cooking ranges, well pumps, EV charging, electric dryers, electric water heaters and pool pumps.

What happens if you overload the Powerwall? ›

What happens if I overload the Powerwall? If you exceed Powerwall's power (5kW each) or energy (13.5kWh each) capabilities, it will safely shut down similar to your home circuit breaker.

How long can Powerwall 2 power a house? ›

Based on the average home consuming 28 kWh/day, one Powerwall will be able to power a home for 12 hours. Two Powerwall's will power a home for 18 hours, and three Powerwall's will run a home for 24 hours.

How many solar panels needed to run AC? ›

Typically, a ton of AC uses 1200 to 1500 watts of power, so you need 6 solar panels of 250 watts to generate that much electricity.

Can solar panels run an RV air conditioner? ›

Yes, it's technically possible to power an RV air conditioner with solar panel. But to generate enough power, a large amount of solar panels and upgrades to the electrical system are required. Or, another device called a “Soft Start.” The vast majority of RV owners will not go to these lengths.

Can I have too many solar panels for my inverter? ›

Under the Clean Energy Council rules for accredited installers the solar panel capacity can only exceed the inverter capacity by 33%. That means for a typical 5kW inverter you can go up to maximum of 6.6kW of solar panel output within the rules.

What do I need in between solar panel and battery? ›

Solar batteries store the energy that is collected from your solar panels. The higher your battery's capacity, the more solar energy it can store. In order to use batteries as part of your solar installation, you need solar panels, a charge controller, and an inverter.

What should I look for in a solar battery charger? ›

There are four key things to look for when purchasing a solar phone battery charger: how much power it produces, if it has a built-in battery pack if it's portable, and if it's compatible with your device you want to charge. You can power more than just your phone with solar!

Are batteries worth buying for solar panels? ›

Solar batteries can be a handy add on to your solar panel set-up. Whilst you can still make full use of your solar panels without a solar battery; the benefits of having solar batteries means you might rely less on the grid and be able to store and use the electricity that your house generates.

How many years do solar panel batteries last? ›

How long do solar batteries last? Most solar batteries on the market today come with a 10-year warranty; however, the lifespan is closer to 20 years. It's essential to have your solar battery in an area that is protected from extreme weather.

Is it better to have more solar panels or more batteries? ›

More panels means greater square footage of solar cells exposed to the sun, resulting in higher efficiency and longer runs times into the earlier morning and later evening when very little sun is available. If you're needing just an hour or two of longer run time, try adding another line of panels.

Do I need a fuse between solar panel and battery? ›

In most cases, a solar system fuse is required between a solar panel and its charge controller because fuses and circuit breakers protect the wiring from overheating. This also avoids any appliances from catching fire or being damaged in the event of a short circuit.

What voltage should a solar battery be charged at? ›

The rated terminal voltage of a 12 Volt solar panel is usually around 17.0 Volts, but through the use of a regulator, this voltage is reduced to around 13 to 15 Volts as required for battery charging.

Why my solar battery is draining fast? ›

It may be that charging and discharging the batteries too quickly is a sign of inadequate battery sizing, improper IMEON settings, or the end of battery life.

How many days will a solar battery power a house? ›

How long can a solar battery power a house? Without running AC or electric heat, a 10 kWh battery alone can power the basic operations of a house for at least 24 hours, and longer with careful budgeting.

Is it cheaper to use batteries or electricity? ›

Will installing a battery save me money? If you have a renewable technology, installing a battery will save you money on your electricity bills, as you will rely less on electricity from the grid. You need to weigh the potential savings against the cost of installation, and how long the battery will last.

What solar batteries have the longest lifespan? ›

Three types of batteries are commonly used in solar storage: lead-acid, lithium-ion, and saltwater. Of these three options, lithium-ion batteries will last the longest.

Which solar battery last longer? ›

Lithium-ion batteries tend to have a longer lifespan and are considered a more reliable solar energy source than lead-acid and saltwater batteries.


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