Home energy storage batteries have been on the market for years with all kinds of varieties and sizes now available. Solar batteries make for smart investments in both residential energy storage and DIY solar projects.
Adventure seekers can now go off the grid with solar batteries to keep their devices running with stored excess energy that can be used at night or on cloudy days. A few solar batteries also do come in handy if you live in conditions where utilities may be unreliable. You can even count on solar power battery storage to run RVs, boats, golf carts, and more.
How Do Solar Powered Batteries Work?
Instead of sending excess solar energy back to the power grid, you can store them instead by installing a solar-powered battery as part of your solar panel system. This means that energy can go back into charging your battery if your panels are producing more electricity than you need.
And when your solar panels are not producing sufficient electricity, you can draw stored energy from the batteries when you need it. The electricity is only sent back to the grid when your battery is full or it draws from the grid when the power cell is low.
The amount of electricity that the system can deliver at once is measured in kilowatts (kW). Kilowatt-hours (kWh) refers to the total amount of energy utilized over an hour. The U.S. Energy Information Administration (EIA) Department states that the average American home will consume approximately 30 kWh a day bringing a total of 901 kWh per month. With a system that provides 2.5 kWh, you will need 12 of them for sufficient daily power.
Since these battery types will self-discharge, the stored energy depletes over time. The rate of self-discharge will depend on the type of battery as well as the age. Newer ones typically deplete at a rate of 1% to 2% per month, whereas older ones could deplete as much as 2% per week.
Residential solar panel arrays don’t usually require backup power. Still, solar panel battery storage lowers your utility bills, protects you from power outages, and reduces your carbon footprint. If you already have solar panels, then this type of battery will work to store energy for the future. However, the most popular battery for solar system solutions like Powerwall and LG Chem RESU isn’t designed to go completely off the grid.
Types of Batteries that Uses Solar Energy
There are multiple types of batteries to consider when choosing a suitable battery product for your solar energy system. Which type is best will depend on your needs and whether you prioritize cost efficiency, safety, or environmental impact.
This term refers to the battery’s ability to complete a discharge-recharge cycle several times. This type of cell is designed to keep a steady flow of power over an extended period. They also come with thick lead plates to help prolong the battery’s life. This type of power cell includes lithium, flooded, and gel batteries.
Lithium-ion batteries are an excellent choice since they’re relatively low maintenance and easy to install. The benefits of having them are that they include higher energy density, less weight, and increased life span. They’re also considered a revolution in housing energy storage solutions.
Similar to the one discussed above, lithium-polymer batteries are more resistant to issues like overcharge or electrolyte leakage. However, they’re more expensive and don’t usually last for as many cycles.
Flooded Lead-Acid Battery
These are also known as wet-cycle batteries, the flooded lead-acid batteries contain the liquid in an open container and disperse hydrogen gas. Flooded lead-acid batteries are cheaper but require frequent regular maintenance since the battery needs to be kept upright and well-ventilated. Flooded lead-acid batteries also need to be monitored and refilled regularly with distilled water.
Sealed Lead-Acid Battery
Sealed lead-acid batteries are valve-regulatory batteries that are maintenance-free. A sealed lead-acid battery is designed to keep the battery from reaching the gas-generating limit while charging, which prevents water depletion and gas dispersal. However, this also means that the sealed lead acid option can never be completely charged.
Ni-cad batteries have a long lifespan if properly maintained. They’re also one of the more rugged battery types available, but they occasionally need to be fully discharged to keep their longevity. However, be aware that cadmium is toxic, so this battery cannot be disposed of in landfills.
If you’re looking for a solar system that is clean and environmentally friendly, then a saltwater battery is a good choice. Like the lead-acid battery, the saltwater batteries offer a natural alternative for clean energy storage. It uses saltwater as its electrolyte, which is nontoxic and nonflammable. These batteries are also low maintenance and have good longevity.
Solar Gel Battery
A gel battery or gel cell is similar to a lead-acid battery. This battery uses gel electrolyte, but unlike a lead-acid battery, you don’t need to keep it upright. In fact, it handles movement very well and will make a smart choice for campers, vans, and boats.
How to Choose the Best Battery for Solar Panels?
As you go on a hunt for the best solar batteries, there are certain specifications that you will need to evaluate such as how long the solar-powered battery will last or how much power it can provide. Below are a few criteria that you need to consider before making the final purchase:
Capacity & Power
Capacity is measured in kilowatt-hours (kWh) and is the total amount of electricity that a solar battery can store. Most housing solar battery designs feature a “stackable” design, this means that you can include multiple batteries with your solar-plus-storage system to achieve extra capacity.
While the capacity tells you how big your battery is, what it doesn’t tell you is how much electricity can be provided at a given moment. To get the full picture, you should also consider the battery’s power rating. This is the amount of electricity that a battery can deliver at one time and is measured in kilowatts (kW).
A battery with a high capacity and low power rating will deliver a low amount of energy for a long time. Whereas a power cell with low capacity and high power rating can run your entire home but only for a short period of time.
Depth of Discharge (DoD)
Most solar-powered batteries need to retain some charge at all times to maintain their functionality due to their chemical composition. If you use 100% of the battery’s charge, the useful life will be significantly shortened.
The depth of discharge (DoD) of a battery refers to the amount of a battery’s capacity that can be used. Most manufacturers will specify a maximum DoD for optimal performance. For example, a 10 kWh with a DoD of 90 percent means that you shouldn’t use more than 9 kWh of the battery before recharging. Generally speaking, a higher DoD means you will be able to utilize more of your battery’s capacity.
Round-trip efficiency represents the amount of energy that can be used in relation to the amount of energy it took to store it. For example, if you feed the battery 5 kWh of electricity and can only get 4kWh of useful electricity back, the battery has 80 percent round-trip efficiency (4 kWh / 5 kWh – 80%). Generally speaking, higher round-trip efficiency means you get better economic value out of your solar battery.
Battery Life & Warranty
For most home energy storage purposes, your battery will typically “cycle” (charge and drain) daily. The battery’s ability to hold a charge will gradually decrease the more you use it.
Meaning they work similar to the battery in your cell phone – you charge your phone each night to use it during the day, but over time you’ll start to notice that the battery isn’t holding as much charge as it did when it was new.
For example, a battery might be warrantied for 5,000 cycles or 10 years at 70 percent of its original capacity. This means that at the end of the warranty, the battery will have lost no more than 30 percent of its original energy storage ability
Your solar battery will also come with a warranty that guarantees a certain number of cycles and/or years of useful life. Since battery performance will naturally degrade over time, most manufacturers will also guarantee that their product will keep a certain amount of capacity over the course of the warranty.
There are many types of organizations developing and manufacturing solar battery products. While a major automotive company entering the energy storage market has a long history of product manufacturing, it may not offer the most revolutionary technology.
By contrast, a tech startup might have brand-new high-performing technology but not much track record to prove the battery’s long-term functionality.
This means that you need to evaluate the warranties associated with each product to act as additional guidance before making your final decision.
The Best Batteries Available for Solar Panels in 2021
In our guide today, we’ve only considered deep-cycle absorbent glass mat (AGM) or lithium-ion batteries as they’ve been proven to provide consistent performance for solar power storage. To select our top picks, we have also evaluated each product’s capacity, durability, as well as overall consumer satisfaction.
1. Vivint Solar LG Chem
- Up to 9.8 kWh
- 10 year’s warranty
Vivint Solar is a company that has partnered up with popular energy innovators such as LG Chem, Tesla Powerwall, and sonnenBatterie to manufacture and provide the best solar battery storage products. Vivint Solar LG Chem batteries feature intelligent management technology to make efficient and eco-friendly power usage simple to use.
If you prefer additional power capacity, you can even link multiple LG Chem residential energy solar units (RESUs) together with either a hybrid inverter or a string and battery inverter. LG Chem lithium-ion batteries are safe for indoor or outdoor solar installations and they even come included with a 10-year performance warranty by Vivint.
2. Sunrun Brightbox
- Up to 9.3 kWh
- 10 year’s warranty
Sunrun is the U.S.’s largest residential solar, battery storage, and energy services company and their Brightbox product is one of the best batteries for solar available for residential rooftop solar systems. This high-tech product even allows you to monitor energy storage and usage efficiency through an internet or cellular connection. You can also set your Brightbox battery to kick in if your electricity usage peaks during the peak time of use (TOY) rates to help you reduce your utility bills.
A Brightbox battery is about the size of a water heater and is designed to be mounted on a wall. Sunrun covers Brightbox with 10 years of warranty, but the batteries can easily last up to 15 years. The Sunrun Brightbox is available to residents in California, Massachusetts, Arizona, New York, Hawaii, Florida, and Puerto Rico.
3. SunLux Enphase Storage
- Up to 10.1 kWh
10 year’s warranty
SunLux Enphase Storage features a smart cell and powerful software that are also easy to install and can be retrofitted into existing systems. Enphase batteries are also safe since they don’t have high-voltage DC in the system and they’re even certified by TUV Rheinland to give you extra peace of mind.
These are lithium iron phosphate (LFP) solar-powered batteries that give you 96% round-trip efficiency with a peak output power of 270 volt-amps. You should also expect the battery to last at least 10 years, and if it doesn’t, SunLux will fix or replace it for you!
Top Picks for Off-Grid Applications
4. Battle Born LiFePO4
- Up to 1.2 kWh
- 10 year’s warranty
Battle Born LiFePO4 battery is our top pick simply thanks to their versatile, cost-effective, and easy-to-install design. You can even choose to bring them along for other off-grid or off-road purposes, including powering campers, golf carts, and boats. The Battle Born company specializes in making non-toxic, renewable energy, so you can rest assured knowing that you’re using clean energy that’s not harmful to the environment.
These high-quality lithium batteries can be charged quickly and discharged repeatedly. Unlike lead-acid batteries, these deep-cycle batteries have the unlimited mounting capability. To top it off, the lithium batteries even come with a 10-year warranty included.
5. Vmaxtanks AGM deep-cycle batteries
- Up to 1.5 kWh
- 10 year’s warranty
These high-quality absorbent glass mat batteries from Vmaxtanks offer tremendous storage capacity. In fact, one consumer is able to run their entire house, including a water pump and a refrigerator with just three of these batteries. Other than that, they’re also very durable thanks to the quality military-grade panels.
This is a popular, maintenance-free battery that’s suitable for residential photovoltaic solar panel systems, smart chargers, and wind turbines. You can even pair it with a quality inverter to get the most out of this battery.
6. Fullriver AGM sealed lead acid battery
- Up to 1.5 kWh
Designed with a high reserve capacity and low internal resistance, the Fullriver AGM combines the performance of a true deep-cycle battery with the convenience and safety of a valve-regulated lead-acid (VRLA) sealing technology.
These lead-acid options have dual top terminals to provide greater installation flexibility, allowing for both recreational and industrial deep-discharge applications. Fullriver DC battery has extra lead to strengthen cell connections, but this also means that the battery is heavier than most at 123 pounds.
Top Picks for Low-Cost Solar Battery Solutions
7. Universal Power Group deepcycle VRLA battery
- Up to 1.2 kWh
- 1 year’s warranty
It should come as no surprise to see Universal Power Group on our list of top picks because of its battery’s versatility, durability, and very reasonable price. This solar-powered battery can be used for home solar power storage or as a mobile charging system. The SLA/AGM technology means that this battery is low maintenance and spill-proof.
These deep-cycle batteries are an excellent solar system choice for small cabins, campervans, and boats. Pairing four of these batteries can easily run 100 watts all day or 1,500 watts for 30 minutes without experiencing a significant voltage drop. Other than that, the Universal Power Group also provides a one-year warranty on this battery.
8. Weize 12V deep-cycle AGM battery
- Up to 1.2 kWh
- 30-day refund policy and 1 year’s warranty
The Weize absorbent glass mat is another top pick of ours because of its high performance and long service life. It also comes with a valve regulated design to make it perfect for small, enclosed areas. These best solar batteries are made with Weize’s high quality, heavy-duty, calcium-alloy grid to fit most universal purposes, including off-grid purposes, trolling motors, uninterruptible power supply systems, and emergency lighting.
In addition to that, Weize includes a 30-day refund policy and a year-long warranty. While the package includes screws, it does not come with a wire harness or mounting hardware. So, you’ll need to purchase them separately.
9. Jackery Portable Power Station Explorer 240
- Up to 0.25 kWh
The Jackery Explorer is a portable power station that’s designed to help you charge smaller devices such as laptops, outdoor electronics, and other devices that operate at less than 200 watts. This is the best solar battery for weekend camping trips and short-term emergency power backup.
This power station weighs less than 7 pounds and comes with a solid handle for you to carry it around easily. It is also equipped with a 250 watt-hour capacity, 14.4-volt lithium-ion battery pack and you can charge the battery with solar panels. It also has a bypass system so that you can run and charge the battery at the same time. An AC adapter and car charger cable come included with the package. You can also choose to pair the power station with a Jackery Solar Saga that’s sold separately.
Our picks for the best batteries for solar for RVs
10. Renogy deep-cycle gel battery
- Up to 2.4 kWh
This rechargeable 12-volt gel battery from Renogy is our top pick for the best solar battery because of its high-quality build for the price and its ability to last a very long time. Consumers also love the fact that this battery is leak-proof and very easy to maintain. The Renogy battery is also equipped with explosion-proof safety valves.
Renogy’s gel battery is designed for solar storage purposes and is suitable for both daily uses and as a battery backup power to small or large solar setups. This heavy-duty gel battery can withstand repeated charge-discharge cycles and its lead-calcium grids ensure a long life of up to 10 years.
11. Powermall deepcycle AGM solar battery
- Up to 0.25 kWh
- 30-day refund policy and 1-year warranty
Powermall’s solar-powered battery is a good value for an RV battery solution thanks to its high discharge rate, wide operating temperatures, long service life, and deep discharge recovery. If you have a boat, you can also use these best batteries for solar energy to power trolling motors and fishfinders. The battery is spill-proof and maintenance-free.
Powermall uses a heavy-duty, calcium-alloy grid for exceptional performance in both float and cyclic purposes. The copper-plated silver terminal on the battery ensures minimal power loss and maintain a reliable power supply. The brand includes screws in the package but not a hire harness for mounting. Additionally, the battery comes with a 30-day refund policy and a one-year warranty.
12. WindyNation deepcycle AGM battery
- Up to 1.2 kWh
The WindyNation high-quality sealed-lead acid battery is one of the best batteries for solar energy usage in an RV because of its low discharge rate that allows for maximum power storage. These batteries are designed for all kinds of off-grid power applications and can be used for solar energy systems on RVs, off-shore marine power, golf carts, and more.
WIndyNation’s sealed-lead acid battery is made with pure, virgin lead and not recycled ones that you often find in lower-quality lead-acid batteries, which makes them ideal for deep, repetitive charges. They are also specifically designed for deepcycle performance and can be discharged and recharged thousands of times.
Conclusion – Is Solar Panels Power Storage Worth It?
Yes, a solar battery is an energy-efficient way to generate backup power. However, those who want to go off-grid may find that diesel generators are cheaper in the short term. A solar-powered battery will make a lot more sense for those living in a bright and sunny area with unreliable utilities or for those who want to go off-grid while relying on renewable energy. A solar-powered battery stores excess energy produced by your solar energy system so that you can tap into it whenever your solar panels do not produce enough electricity to power your devices.
Frequently Asked Questions
Q1. How much does a solar-powered battery cost?
A small solar system battery will run between $200 and $2,000. However, if you want a quality battery for residential solar energy storage, you should be prepared to pay up to $7,000 or more. When comparing the prices, you should consider the cost of battery storage per kWh (kilowatt-hour), which ranges from $400 per kWh to $750 per kWh.
Q2. How many solar-powered battery systems are needed to power a house?
Most homeowners will need between two and give battery systems to effectively power a house. Depending on your energy usage, you can connect several systems in series or parallel battery banks with interconnecting cables. Most of these battery systems are stackable, meaning you can install multiple of them with your solar energy system to reach the right battery capacity for you.
Q3. Why are solar panels so expensive?
Solar panels are expensive because the materials required to produce them are expensive. However, prices are expected to drop as technology advances.
Q4. How long do solar energy system batteries last?
Generally, a fully charged solar-powered battery should be able to power your home for 12 to 24 hours. However, there are other variables such as household energy consumption, battery capacity, and whether you’re connected to an electrical grid that will come into play to determine how long your battery will last.
A solar battery’s lifespan can be anywhere between five and 15 years. You can also do your part by ensuring proper regular maintenance and protecting it from extreme temperatures to extend your battery’s life.
Q5. What is a battery bank?
A battery bank is a collection of battery systems that are connected. A battery bank allows for more power storage than you can get from just a single battery.