In recent times, solar energy has gained attention from consumers all around the world. With electricity costs increasing drastically, it is not surprising to see most homeowners purchasing solar panels. However, with solar energy comes the question of solar battery storage. How do you know which solar battery is the best for you?
There are many options available and that makes the whole prospect of buying a solar battery daunting. Not to mention, the idea of home energy storage is relatively new to people.
In this post, we have compiled all the essential factors you must look out for when purchasing a solar battery.
Solar Batteries: Worth the Hype?
If you really want to take the advantage of your PV system, you require a good solar battery. When it comes to their cost, there is no doubt they are pricey. Typically, they cost around 10,000-20,000 dollars. However, if you can afford the cost, you can definitely enjoy some substantial benefits of installing a solar battery.
The costs of solar batteries are decreased because the 30% FSI tax credit applies to them. It helps in decreasing the costs to a significant extent.
Solar batteries offer multiple benefits. They do not just store solar energy. Instead, they serve as a power generator for abrupt emergencies and even help you reduce your electricity bills. Not to mention, they also bring the carbon footprint of your house down. In the long run, the installation of solar batteries can even raise the value of your property. For most solar batteries, the payback period is often 5-7 years. But it often depends on some other factors like available incentives, system design, and total capacity.
Moreover, with technological advancements, more efficient batteries are available. Therefore, homeowners have a wider array of solar batteries and types to choose from. So, what are some common types of solar batteries?
Types of Solar Batteries
Well, there are two primary categories of solar batteries including sealed and flooded solar batteries. Usually, flooded batteries are used because they are your conventional lead-acid batteries and they are mostly used in off-grid systems and vehicles. Since they can be serviced and cleaned easily, they are quite affordable. Not to mention, their lifespans are longer. But they emit hydrogen gas when they are being used.
On the other hand, sealed batteries are different because they cannot be maintained and serviced. In order to increase their lifespans, plates and fluids are maintained by a charge controller. When they are used, hydrogen gas is not emitted.
- Lithium-Ion Batteries
Electric vehicle manufacturers use lithium-ion batteries the most. Even though their potential as a medium of energy storage has not been fully realized yet, they still offer a promising storage solution. Still, they are being improved rapidly and it is only a matter of time before they become the first choice of homeowners. The Powerball battery by Tesla is perhaps the most popular solution that really utilizes it.
In the market, you can find two types of Li-ion batteries. They are LiFePO 4 and NMC, which are widely used by electric vehicle manufacturers. It is primarily because the NMC battery comes with a high life cycle, which makes it suitable for off-grid applications. On the other hand, LiFePO batteries tend to work efficiently in high temperatures. Therefore, they are often used in areas and regions that have high temperatures.
Pros: In contrast with other types of batteries, Li-Ion batteries do not require any maintenance. In addition, their energy density is higher. It means that compared to lead-acid batteries, they can store more energy. Their depths of discharge and lifespans are longer because their life cycles are longer. For instance, at 80 percent depth of discharge, they can offer 4,000-6,000 cycles. Still, they can stay with you for 15 years.
Cons: One of the key drawbacks of Li-Ion batteries is they are costly. Compared to the prices of lead-acid batteries, their prices are double. Not to mention, they are rather fragile.
- Lead-Acid Batteries
For electrical energy storage, lead-acid batteries are widely accepted and used. For starters, they have been around for centuries now, and even now, they are used mostly in storing power. In fact, lead-acid batteries were considered the only practical solution to store energy until a few years ago.
Actually, for off-grid solar installations, they are considered the first choice. Both their stability and price make them reliable and easy to replace or upgrade. In the country, most emergency backup systems utilize these batteries.
Pros: The prime benefit of a lead-acid battery is its affordability. In both remote and rural areas, they are installed widely. Compared to other options, they are cheaper and can deliver the required outputs for a long time steadily. In addition, they offer a constant discharge rate and they come in both sealed and flooded types. The same principle is used in both types.
Cons: Lead-acid batteries are heavy and bulky due to which they require sufficient space. To maintain their outputs, you need ambient working temperature.
- Sodium-Nickel Chloride Batteries
If there is a battery that competes with a lithium-ion battery, it is definitely a sodium-nickel chloride battery. This type of battery is recyclable due to its unique chemistry. For instance, it has no fire or heating risks and does not emit any toxic chemicals in the environment. Moreover, in contrast with lithium-ion batteries, these batteries do not need a heavy-duty cooling system.
Pros: Sodium-nickel chloride batteries are widely regarded as reliable and safe options due to their chemistry. For example, even under extreme temperatures, they can work optimally and are fully recyclable. They can be recycled because they do not house any toxic or hazardous chemicals.
Cons: They do not have a longer lifespan. For instance, they deliver only around 3,000 cycles, and 20 percent of the battery it stores cannot be used. For large projects such as solar installations, they prove to be very costly. Therefore, they are often not considered for solar projects.
- Flow Batteries
You may not have heard of flow batteries before but they also have wide applications. They are also recognized as redox flow and utilize bromine and water-based zinc solution for the storage of electrical charge. Since it is a new entrant, not many companies are producing these batteries.
Pros: Since they are scalable, it is possible for the output and capacity of a flow battery to decrease or increase proportionally to its size. These batteries are different from others because deep discharge does not influence their lifespan or performance. They have a low self-discharge and a long life cycle. When they are being used, they do not really heat up.
Cons: Flow batteries are very expensive due to the costly nature of fluids in them. Even though their basic technology has been around for a while, not many companies produce them. Due to their chemistry, these batteries are quite bulky and consume a lot of space. Not to mention, the bromine and zinc elements in flow batteries are toxic and corrosive.
Important Factors to Look Out For
Now, you should consider these factors before you purchase a solar battery from a battery store:
- Power Rating
Usually, a power rating indicates the electricity a battery can deliver or produce at once. It is typically measured in kW or kilowatts. In other words, it shows which appliances and how many items you can run at the same time without any problem. Most solar batteries are equipped with two power ratings. They are a peak power rating and a continuous power rating.
The former is actually the maximum or optimal amount of electricity your battery can produce for a short amount of time. It lets you run all those appliances that require a burst of power to operate such as an AC. Meanwhile, the latter represents the amount of electricity your battery can deliver continuously for all those appliances that require a steady and constant power supply.
Normally, solar batteries have peak power ratings and continuous power ratings of 7kW and 5kW respectively. Thus, you need a battery with higher power ratings if you are looking to power up many appliances at once.
- Capacity Rating
As the name implies, it indicates how many kWh or kilowatt-hours of electricity your battery can store. On the other hand, the usable capacity shows how long your batteries can deliver electricity to your house.
There are some batteries that show you two capacity ratings: the usable capacity and the total capacity. You need to look out for usable capacity, which indicates the battery capacity that you can use.
Out of all the batteries, you should select a battery that comes with a rating of a minimum 10kWh. It is mainly because they are suitable for the energy requirements of most homeowners. At the same time, it offers a substantial amount of backup. Therefore, even if there is a blackout, you can still power your appliances.
It is possible for homeowners to use multiple batteries to raise the capacity of their storage system.
Usually, lithium-ion batteries have a lifespan of around a decade. With consistent use, a battery degrades and its ability to store charge is decreased. For instance, when you continue to use your mobile phone for years, its battery begins to fall faster. The same applies to your solar battery. Even if you get the best batteries, it is bound to happen.
You can measure the battery lifespan using estimated throughput, estimated cycles, and years. The life cycle indicates the number of times your batteries can be discharged and charged completely. Meanwhile, the throughput represents the estimate of electricity that can be released by a battery over a specific period of time.
You must look for a solar battery that is warranted to work at around 70 percent of its actual capacity after a decade.
- Round-Trip Efficiency
A solar battery’s round-trip efficiency represents the amount of energy you can take and utilize from your battery compared to the amount of energy that was used to charge the battery.
Let’s suppose your solar panels transferred 10 kWh of electricity to the installed batteries. However, only 7 kWh of that energy can be used. It indicates that 3 kWh was utilized by the operating system of the batter to release and store the electricity. Therefore, its round-trip efficiency is around 70 percent.
You should look for a solar battery from a battery store that offers a minimum efficiency rating of 80 percent.
- Safety Rating
Almost all solar batteries you can find in the market meet a specific set of safety requirements before they can be applied or installed. Still, there are certain batteries that are safer than others. For instance, NMC batteries are more prone and sensitive to changes in temperature. Therefore, they can catch fire if they are not handled properly.
On the other hand, LFP batteries are safer because they are more resilient to changes and fluctuations in temperatures. Since they are unlikely to catch fire, they can be installed without any worries about a burnout.
Even though solar battery installation depends on the number of batteries and the system you have installed, it will cost between 9,000-14,000 dollars on average. Still, you can get the federal solar tax credit and reduce the overall costs.
You can look at the cost per hour of different batteries. Select a battery that offers a more competitive rate in the long run.
Overall, selecting the best battery for your solar panels is essential. Otherwise, you will be wasting the potential and energy your solar system is producing. However, even from the best battery store, it can be difficult to find the best batteries. Since solar batteries are expensive, you must make the right choice to avoid wasting your money. There are several factors you need to consider such as cost, type of battery, safety rating, and output among others. When you are aware of these factors, you can compare different batterie and select the right battery for your solar panel system. It can help you get the best out of your solar system.