Batteries for Solar Panels: How to Choose Them and How They Work -
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Batteries for Solar Panels

batteries for solar panels

Solar power is currently one of the most popular means of the alternative energy production market. The most basic way in which you can produce solar power yourself is via a solar power system using solar panels and batteries

If you’re in the process of installing solar panels on a boat or installing solar panels on a van, let alone on your house, it’s important to remember that the functioning and overall efficiency of solar panels can be significantly boosted through the use of solar power batteries.

In this article, we walk you through just about everything there is to know about solar batteries for solar panels, namely: what they are, how they work, the forms in which they exist, and what you need to look for when you’re choosing solar batteries for your solar off-grid system

best batteries for solar panels

What are Solar Batteries?

Solar batteries are pieces of equipment that store all the energy your solar panels produce throughout the day, as well as any excess energy. This allows you to use it at later points in time like at night or early in the morning when the sun isn’t shining.

As long as the sun is up, your solar panels produce as much energy as their efficiency rate allows in relation to how much sunlight they’re receiving. However, sometimes solar panels produce more energy than what’s required to power your appliances.

If there’s nowhere to store this excess power, it simply goes to waste. In this way, solar batteries help you get the most out of your solar panels and ensure that you’ll never be without power, even when your solar powers are no longer producing any more energy

Batteries collect the energy flowing from the positive end of the solar panel to the negative before sending it out to the rest of the system that’s wired independently. 

Comparing and Choosing Solar Batteries

Before we look at the different types of solar batteries on the market for you to choose from, it’s important that we go over the factors that you will need to consider when you’re choosing the perfect battery for your solar power system.

Below, we’ve compiled a list of some of the factors that we here at Shop Solar Kits feel are the most important to consider in this regard.  

what batteries to use with solar panels


Although, according to the famous saying, size doesn’t matter, when it comes to choosing a battery for your solar power system, size is one of the first things you’ll need to look at.

The size of a battery, also known as its capacity, is what determines how much energy a battery is capable of storing. This means that the larger the capacity of your battery is, the more power it can store and ultimately, the longer it powers the things you wish to power.

Therefore, if you wish to power something that requires a lot of power, say your entire home, you not only need to invest in a number of solar panels to produce as much energy as possible, but also in a large battery that is capable of storing such large quantities of energy.

When it comes to this attribute it’s important that you spend some time calculating your energy needs beforehand. This means you know the amount of energy you will be working with on a daily basis and, ultimately, the size of the battery that will be best suited to accommodate this energy quantity. 

Power Rating

The power rating, also known as the depth of discharge, of your solar battery goes hand-in-hand with its storage capacity. Where a battery's capacity determines how much energy it can store at a time, its power rating determines how much of this energy can be used all at once.

Again, in this regard calculating your energy needs will help you see how much energy you will need to power everything. The higher this energy requirement is, the higher the power rating of your solar battery needs to be.

Roundtrip Efficiency

When it comes to any solar power system, efficiency is generally the primary factor that you’ll need to prioritize. With solar energy, it’s all about getting the most out of each component in your system to ensure that you are producing as much solar energy as you possibly can at one point in time.

best batteries to use with solar panels

With regards to solar batteries, efficiency depends on their roundtrip efficiency rating. The roundtrip efficiency of your solar battery is the measure of how much of the energy you are injecting into and storing in your battery you will be able to get out of it again on demand.

In this regard, it’s important to note that when you put a certain amount of energy in a battery, you won’t always get that exact same amount of energy back gain. This is because there are certain electrical processes that use some of this energy in the retrieval process and so this energy is lost.

This is where the roundtrip efficiency of your battery comes into play. The higher the roundtrip efficiency rating of your solar battery, the less energy will be lost when it is retrieved and so you’ll have more energy at your disposal at one point in time. 


It goes without saying that, as with any solar power component, you always want to get the best value for the money you’ve spent. The longer a component lasts the more value you’re getting for your money and so it’s also important to consider the lifetime of a battery before purchasing it.

The lifetime of a battery is represented in relation to throughputs and cycles. Throughput represents how much energy a battery will be able to accommodate and have moved through it during its lifetime and cycles represents how many times you can charge and use a battery before it expires. 


The batteries are considered to be the most dangerous component of any solar power system. This is because, at any given time, your battery could be storing large quantities of energy using complex electro-chemical processes.

If anything were to go wrong in this process, this energy could be rapidly released in the form of an explosion that would not only be detrimental to your property but to your health as well. For these reasons, all solar batteries have to undergo a strict line of safety tests to ensure that this does not occur.

Always consult the safety rating of a solar battery. Sometimes a high safety rating may cost a bit more, but we here at Shop Solar Kits always say that you can’t put a price on your own safety.

best batteries for solar panel storage

Types of Solar Batteries

Now that we understand what solar batteries are, how they work in general, and finally what sets good solar batteries apart from the rest,  we can turn to distinguish between the different types of solar panels on the market.

Each of these types of solar batteries essentially works the same but, as you’ll see below, they differ in some important ways. It’s important to understand these differences so that you know which type of battery will suit your purposes best.  

Lead-acid Batteries 

Lead-acid batteries have been around for more than 150 years. When you think about any basic rechargeable batteries, this is the type of battery you’re dealing with. As such, it’s clear why they’re regarded to be the most commonly used type of battery.

That being said lead-acid batteries are now generally to be a more primitive form of power storage now that the likes of lithium-ion batteries and flow batteries have emerged on the scene. This is because they’re known for having lower capacities and power ratings than lithium-ion batteries as well as shorter lifespans.

All-in-all, lead-acid batteries still remain one of the most inexpensive types of batteries on the market which is a fact that should by now means detract from the overall efficiency or performance of these batteries in the setting of a solar power system.  

Lithium-ion Batteries

Lithium batteries are the most modern type of solar battery on the market that first emerged on the solar power scene in the 1970s. Their use was originally most popular in cellular phones and portable computers, but their potential in the field of renewable energy has since been recognized as well.

what kind of battery for solar panel

Although lithium-ion batteries are generally the most expensive type of battery on the market, you’ll find that they’ll be worth every penny. This is because these batteries are known for their extended lifetimes, high power ratings, large capacities, and overall excellent roundtrip efficiency.

Flow Batteries

Flow batteries are predicted to be the way of the future. This is a new experimental technology that has emerged on the scene in recent years and is expected to become more popular than lithium-ion batteries in the new future.

The reason there’s so much excitement surrounding these batteries is that they have a 100% power rating. This means that all of the energy that enters your battery can be used at the same time.

In addition to this not only are they simple and easy to use, but they’re environmentally friendly in the sense that they use little to no rare and expensive metals in their production and composition.

It must, however, be noted that we only included this type of battery on the list for interest’s sake. These batteries are still in their developmental stages and still experimental. As a result, they’re not yet on the market for residential purposes.

Reasons to Get Batteries for Solar Panels

Sadly, solar batteries don’t come cheap. That being said, you’ll take comfort in knowing that, while they may leave a dent in your wallet at first, there are a number of reasons why adding a solar battery to your solar power system can be an absolute game-changer.

Let’s take a look at some of these reasons.

best batteries for your solar panel storage

24/7 Power

If your solar power system operates without the use of solar batteries, it will mean that you are directly depending on the amount of sunlight that your solar panels are receiving and, consequently, how much energy your solar panels are producing at a certain point in time.

Conversely, if your solar panels are connected to a battery within which they can store all the energy they produce, including any excess energy, you will have an endless amount of power around the clock and so you’ll always have power at your disposal regardless of whether the sun is up or not. 

No Fluctuations in Power Rates

Adding a battery to your solar power system means that you will have to rely less on grid electricity in general, if you even have to rely on it at all.

This means that you will no longer fall victim to the ever-fluctuating utility rates of grid electricity because you will be producing your own power at the same fixed rate at which it takes you to pay off your solar power system and reach its break-even point.

In addition to this, as a solar power producer and the user you’ll also qualify for certain tax deductions and other government incentives. These incentive are meant to encourage people to invest in ecologically-friendly power that takes them off the grid.

best batteries to use with solar panel

Enhanced Oversight and Monitoring

If you’re able to store the energy that your solar panels produce throughout the day, you’ll find that it’ll be a lot easier to keep track of how much energy your system is producing throughout the day as well as how much of it is being utilized and how much of it is being stored as excess energy.

In this way, a solar battery is a means of enhancing the oversight you have of your solar power system because it allows you to monitor its performance in a way that is both easier and more precise. 


There are a number of ways that people generally attempt to make their solar power systems more efficient. Some have tried two charge controllers one solar panel and others have tried mixing different wattage solar panels in an attempt to produce as much power as possible.

Whilst these are both valid solutions, after reading this article it should be very clear that if it is efficient that you’re looking to add to your solar power system, batteries for solar panels should be your point of departure.

In this article, we’re sure that we’ve not only helped you understand a lot more about the role batteries play in solar power systems. We hope to have illustrated that the problems of setting up off-grid solar panels are really not as daunting as they might have seemed at first.

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