Best Batteries for Solar

scanning: time:2021-09-24 classify:Technology info

Which solar battery best suits you?

Equipped with all the above information, all you need to do now is to determine what your power needs are, along with your budget

If you have these two details, you can easily select from the above list and get tremendous solar battery storage for your solar system.

These are all great options for anyone seeking to use a battery to live off-grid.

What are Solar Batteries?

With unreliable solar battery storage, you will only be able to enjoy solar power when the solar panels are producing it.

Solar batteries are crucial to help you keep your system running.

Moreover, since the panels produce energy during the day, and you may not use all the energy at the time, a stable power bank is essential to store this energy.

With no proper type of solar batteries, you may require to contend with the lack of power, especially if there are outages in the utility grid. To get the best batteries for solar panels, here is a guide for your reference.

Solar batteries refer to devices which store the energy generated from the solar panels for later use. The solar batteries ensure that you can continue to enjoy solar power even after sundown, during a power outage or the energy demand peaks. These batteries can be used in residential properties, as well as in commercial buildings.

Solar batteries play a vital role, especially in the off-grid solar systems. They act as the heart of the off-grid solar system.

When building a solar power system, solar batteries should be a priority as they will determine how effective the system will be to you.

Using the batteries, you optimize your ability to use solar power daily. In instances where you require more energy than your panels produce, you can readily use the stored energy from the batteries.

What is a Solar Panel Battery Pack?

A solar panel battery pack is a package that makes up the solar power storage in a solar system. The first items in the pack are the solar panels that help to collect sunlight energy and change it into DC electricity.

Secondly, it we what the battery system (what you are reading about right now!) that enables the storage of the power the panels produce.

And finally, an inverter which converts the direct current (DC) to alternating current (AC) that is usable in homes.

How Does a Solar Battery Work?

The solar batteries work by storing the energy generated from the solar panels during the day. They save the energy in the form of DC energy and therefore, you will require a power inverter to convert the DC energy into AC energy.

Mostly, you will need either 120V or 230V for use in your home.

Another vital component of solar batteries is the solar charge controller. This helps to ensure that the energy produced during the day does not overcharge the batteries.

Also, it prevents the power stored in the cells from running back to the panels and draining the batteries over the night.

How to Select the Best Batteries for Solar Systems

Whereas there are numerous advantages of acquiring a battery system for your solar, there are also multiple challenges in finding the right ones. The fact that they are expensive and hard to replace after installing the solar system makes it more crucial to choose right.

There are many solar battery types in the market, that may prove challenging to differentiate, and that’s why I will show you the best way how.

The different challenges that occur during the purchase include cost, ease of installation, storage capacity, and battery lifespan, among others.

To save you the struggle, let us delve into it and see how you can choose the best batteries for solar panels.

The Different Categories of Batteries

To better understand how you can easily choose the right solar battery, you should first know the broad classes of these batteries.

There are three options of cells you can choose from which include the sealed lead-acid, flooded lead-acid, and lithium batteries. Let’s go through them one by one to help you understand.

1. Flooded Lead Acid Batteries

For the longest time, the most popular solar batteries for a home have been the flooded lead-acid batteries. This model of solar cells has been in use for over 150 years and has been a great asset, especially to the off-grid systems.

Flooded lead acid batteries, also referred to as wet cells, are very affordable and are also 99% recyclable.

With their design, they can easily handle the daily charge cycling. The significant advantages of these batteries include their low purchase cost, reliability, and safety. However, this category of cells has a good measure of drawbacks.

These batteries are known to produce a byproduct in the form of a gas, and therefore, ventilation is essential where they are located. Another major disadvantage is that they are bulky and corrosive. Also, they demand maintenance checks regularly. The batteries must also be kept in an upright manner to avoid leakage.

Flooded lead acid batteries are made of cells whose plates must be kept underwater for them to function correctly. This is the reason they are referred to as “flooded.” You need to check and add water every after 1-3 months to ensure the plates remain submerged.

For those who don’t mind the regular maintenance and monitoring, these can be the right choice. They are also the most affordable category of solar batteries.

However, due to the multiple drawbacks, many most homeowners are shifting to the use of other models which have fewer maintenance demands.

2. Absorbent Glass Mat (AGM) Batteries

The second category of batteries is the AGM Batteries. From the early 1980s, this technology started gaining popularity with a sealed lead-acid battery being made for the military vehicles, aircraft, and UPS. These AGM batteries are part of a category of lead-acid batteries called the sealed lead acid.

In this form of a lead-acid battery, a fiberglass matt is used to absorb the electrolyte.

In the AGM batteries, the plates are either flat just like in the flooded lead-acid, or coiled into a spiral resembling those in Optima batteries.

One primary advantage of AGM batteries is that they possess a lower internal resistance than that in flooded cells. Therefore, these batteries can endure higher temperatures, as well as discharge slowly, more than the rest of the batteries.

Unlike the flooded lead cells, the cells in AGM batteries are leak-proof, and they also require less or no ventilation. However, just like the flooded batteries, they use the same charging voltage and tend to be more well-suited for solar electricity systems.

This compatibility means that they can be integrated with flooded cells, although we mostly don’t advocate for the setup due to the negative effect on battery life.

The other advantages of using AGM batteries include the fact that they are not hazardous, their resistant to cold temperatures, and they are relatively lightweight.

Also, they are less prone to heating up (due to the low internal resistance), and they can also preserve a static charge for long periods. AGM batteries, unlike the flooded batteries, have a longer lifespan and just slightly expensive than their counterparts.

Generally, they are an excellent choice for an off-grid solar system.

3. Gel Batteries

Another type of sealed lead-acid batteries is the GEL Battery. These batteries specialize in deep-cycle applications and use fumed silica to form the thickening agent for the electrolyte. The fumed silica helps to make the cells sturdier.

Some other advantages of Gel batteries include that they durable, requires no maintenance, and they have high resistance to vibrations and shock. The cells also work well in both hot and cold temperatures and have great life-cycles. Also, with the viscous electrolyte, the cells become less prone to leakage in case of damage.

Nonetheless, GEL batteries have more disadvantages than the other types of batteries, making them less popular. These batteries are ventless and they self-discharge a bit faster than the flooded cells.

Other common disadvantages of this category of batteries include their narrow charging profiles, and they are easily damaged if charging is not done right.

The batteries also lack ample amp-hour capacity, and their low charging voltage can make them disposed to accidental overcharge.

Especially with solar power systems, electricity generation is a bit variable and can cause this overcharging. In addition to the numerous drawbacks, Gel batteries are also more expensive than the flooded lead-acid batteries.

4. Lithium-ion Batteries

The last category in this list is lithium batteries. They consist of a newer technology that became available from the 1970s and has been in use mostly in cellphones and laptops. However, the cells have become increasingly popular in the renewable energy industry in recent times.

Although more expensive than other types of batteries, lithium batteries offer multiple benefits that compensate for the price.

These advantages include longer lifespan, higher efficient power usage, no maintenance, deeper discharges (more storage capacity), no gas emission, and more. These can typically be the best batteries for solar panels.

In the recent past, people have increasingly shifted from the traditional flooded lead-acid batteries and are more focusing on lithium-based cells.

They are also instrumental in cordless power, including cordless air compressors, and cordless impact wrenches among others. These batteries are small in size and are significantly light judging by their high capacity.

Lithium-ion batteries are easy and efficient to charge, and also, they have long lifespans. The long lifespan is the main advantage of lithium batteries as it ranges from 3000-5000 cycles.

Their high and efficient charge and discharge also is a plus as it helps to optimize the power generation from the solar panels.

The low discharge feature is ideal in solar installations as it helps retain power for more extended periods for later use. With all these benefits lithium batteries are an excellent choice for your solar panel battery bank.

Any solar system, whether small or large, grid-tied or off-grid, lithium batteries are ideal for all. One major disadvantage of lithium solar batteries is their cost.

They can cost as much as four times more than the flooded solar cells. But if price isn’t your main concern, there’s no denying Lithium-ion make for osme of the best solar batteries.

What is the best voltage for your solar battery system?

The voltage question may seem irrelevant, but it is essential. Before you buy and install that battery energy storage system, you should decide which voltage your battery system will be made of.

For example, the batteries can either be 12V, 24V, or 48V. Which fits your needs better? This is something you should be aware of before the installation.

Since it is challenging to change the voltage after installing your power storage system, it becomes critical, therefore, to make the correct choice. The 12V battery is the purest form of battery and the most commonly used one in cars, boats, RVs, and more. If you require a simple power storage system, then the 12V battery system will be enough for you.

Presently the 24V and the 48V storage systems are the most commonly used in the solar systems. The reason behind this is the technical advantages they have as compared to the 12V.

In essence, higher DC voltages translate to lower costs. It also translates to a lower current for a similar amount of power.

For example, 2,000 Watt is equal to 166 amp @ 12V, 2,000 Watt is equal to 83 amp @ 24V and 2,000 Watt is equal to 41.5 amp @ 48V

Moreover, as more and more customers seem to require more energy over the years, the 12V DC system is not ideal. If for instance, your solar panels exceed 500 watts, you should consider a 24V system. On the other hand, if you plan to live off-grid, the 48V system will be ideal.

Use an electrician to help you to determine the optimal performance.

What to Consider When Choosing a Solar Battery

Even with all that information, you may still not be ready to jump into that purchase.

There are several factors you should always research before making that final choice. These features include:

The Size of the Battery

The battery size is the first most crucial thing you ought to consider when buying a solar battery. The size in this context means the energy storage capacity of the battery. Although the physical size of the battery will also matter based on the space you have for installation, the capacity is most important.

When looking at size, you should consider both the capacity and the power rating. For instance, a battery with low power rating and high capacity will only power a few appliances in your home, but for a long time.

On the other hand, if it has a low capacity but high rating power, it will power most of your appliances but for a shorter period.

Therefore, you should look for a battery with high capacity, as well as a high power rating. With this kind of a cell, you can power multiple appliances at your home, and for more extended periods.

Ease of installation

If especially you have no much prior knowledge on the solar systems, you require a battery system that is easy to install. Essentially, it is wise to seek advice on the same from people who have prior experience or professionals.

If you want a battery system that is maintenance-free, easy to install, and that requires relatively low space, the lithium-ion batteries are your best choice.

Don’t go for a system that will consume a lot of space or that will require so much expertise to install. The easy it is to install, the less time it will absorb and most probably, the less installation cost you will incur.

If you have a larger generation need for off-grid applications, you’ll likely want to consider hiring an electrician. This will help ensure that you have the appropriate installation upfront.


When it comes to purchasing any item, the cost is a significant influencer. In selecting the best batteries for solar power storage, this is no different.

Although not always, price, in most cases, reflect the quality of an item.

Therefore, don’t rush into buying a battery just because it is cheap. You should consider all the other factors and compare them to the price.

As a general view on the solar panel battery cost, the higher the battery costs, the more benefits that come with it.

Charging Time

With charging time, some batteries charge faster than others. Different battery types will have varying charging rates with others being fast and others slow.

If you want to maximize the amount of energy generated from your solar panel system, then you need a fast charging solar battery. For those who care about the rate at which the battery charges, Gel batteries are the best choice for you.

Other categories of solar batteries such as the flooded lead-acid ones, take considerably more extended periods. They can take as long as even a whole day to get fully charged, which is long. Lithium-ion batteries, on the other hand, also have good charging speeds of around 3 hours.

If the battery charges fast, then the better for you as you can use the energy as fast as possible. A combination of an ideal battery and an excellent solar battery charger is vital to guarantee high charging speeds.

We have a full guide to solar battery charging you can check out to learn more.

Manufacturer Warranty

A manufacturer’s warranty is the next most crucial thing that you should take into consideration. Since the solar batteries are significantly expensive, you can’t afford to have a breakdown in the next few years after installation. It is wise to ensure any malfunction that may occur will be sorted.

The longer the warranty period, the best it is for you. Typically, more expensive brands offer more extended warranties than the less known and cheap ones. For solar storage batteries, a reasonable warranty period ranges somewhere from 20-30 years.

The Lifespan of the Battery

The lifespan of a battery means the period the battery will be useful before it loses its ability to hold a charge. You can measure solar batteries’ lifespan in terms of hours, days, or years, and the length depends on the type, size, or brand.

If you need a sure long-lasting and robust battery, be ready to dig a bit deeper into your wallet.

Long-lasting batteries will, in most cases, cost more than the lesser durable ones. Each brand of battery has its estimated amount of time they will remain useful. You should carefully check on this before you decide on the Solar cell to purchase.

Conclusion on Best Batteries for Solar

When it comes to solar power systems, energy storage is of paramount importance. For you to enjoy solar energy, especially if you live off-grid, reliable solar energy storage is a must-have.

In this solar battery buyer’s guide, I believe that you will get everything you need to help you choose the best batteries for solar power to suit your needs.

For most peoples needs we recommend the Brava Batteries BPG12-100 AGM 12V due to their excellent performance, long life span and relative value for money.

If you’re looking for a cheaper option, the Brava Batteries BP12-100 12v 100Ah Rechargeable Deep Cycle Battery is also a solid choice.

We hope you’ve found this guide helpful in deciding which battery to buy

What is a solar battery?

A solar battery bank is simply a battery bank used to store excess solar electricity that is surplus to the power needs of your home at the time it is generated.

Solar batteries are important because solar panels only generate electricity when the sun is shining. However, we need to use power at night and at other times when there is little sun.

Solar batteries can turn solar into a reliable 24x7 power source. Battery energy storage is the key to allowing our society to transition to 100% renewable energy.

Energy storage systems

In most cases homeowners are no longer being offered solar batteries on their own they are being offered complete home storage systems. Leading products such as the Tesla Powerwall and the sonnen eco do contain a battery bank but they are much more than this. They also contain a battery management system, a battery inverter, a battery charger and also software based controls that allow you to control how and when these products charge and discharge power.

All of these newer all-in-one home energy storage and energy management systems use Lithium Ion battery technology and so if you have a home that is connected to the grid and are seeking a solar battery storage solution you no longer have to consider the question of battery chemistry technology. It was once the case that flooded lead acid battery technology was the most common solar battery bank for off grid homes but today there are no packaged home energy management solutions using lead acid batteries.

Why is lithium-Ion battery technology now so popular?

The core advantage of lithium ion battery technologies that have caused their almost uniform adoption in recent years is their higher energy density and the fact that they do not vent gases.

High energy density means they can store more power per cubic inch of space than the deep cycle, lead acid batteries that were traditionally used in off grid solar systems. This makes it easier to install the batteries in homes and garages with limited space. This is also the key reason they have been favoured for other applications such as electric cars, laptop batteries and phone batteries. In all of these applications physical size of the battery bank is a key issue.

Another important reason that lithium ion solar batteries are dominating is they do not vent toxic gases and so can be installed in homes. Older flooded lead acid deep cycle batteries that were traditionally used in off gird solar power systems did have the potential to vent toxic gases and so had to be installed in separate battery enclosures. In practical terms this opens up a mass market that was not there before with lead acid batteries. We feel this trend is now irreversible because all of the electronics and software to manage these home energy storage solutions is now being built to suit lithium ion battery technologies.

Are solar batteries worth it?

The answer to this question depends on four factors:

  1. Do you have access to 1:1 net metering where you live;

    1:1 net metering means that you get a 1 for 1 credit for each kWh of excess solar energy that you export to the public grid during that day. This means that if you design a solar system to cover 100% of your electric usage you will have no electric bill. It also means you don't really need a solar battery bank because the net metering law is allowing you to use the grid as your battery bank.

    The exception to this is is where there is time of use billing and electric rates in the evening are higher than they are during the day (see below).

  2. How much excess solar energy do you have to store in a battery?

    There is no point having a solar battery unless you have a solar system that is big enough to generate excess solar energy during the middle of the day that can be stored in the battery. This is kind of obvious but it is something you need to check.

    The exception to this is where there is time of use billing and electric rates in the evening are higher than they are during the day (see below).

  3. Does your electric utility charge time of use rates?

    If your electric utility has time of use electric billing such that power during the evening peak time is much more expensive than it is during the middle of the day then this can make the addition of an energy storage battery to your solar system more economic. For example if electricity is 12 cents during off peak and 24 cents during peak then each kW of solar energy you store in your battery will save you 12 cents.

  4. Are there specific rebates for solar batteries where you live?

    It is obviously much more attractive to buy a solar battery if part of the cost is going to be funded by some form of rebate or tax credit. If you are buying a battery bank to store solar energy then you can claim the 26% federal solar tax credit on it.

AC-coupled vs DC-coupled solar batteries

Solar panels produce DC (direct current) electricity. Batteries charge and discharge DC electricity. Home appliances, however, use AC (alternating current) power.

Solar power systems with storage - that is, hybrid and off-grid systems - manage AC and DC power flows differently based on whether they’re using an AC-coupled battery or a DC-coupled battery.

Here’s how each type of battery system works:

AC-coupled batteries

In recent years, AC-coupled batteries have become the most popular battery solution for solar-plus-storage setups.

DC power is generated by the solar panels, and then converted to AC power by a standard grid-tie inverter. The resulting AC power can be used for multiple purposes: it can power the home, be exported to the grid, or be sent straight to an AC-coupled battery for storage.

This is possible because AC-coupled all-in-one battery storage systems contain electronics that:

  • Convert incoming power from the grid-tie inverter from AC to DC

  • Manage the charging and storage of DC power in the battery cells

  • Convert outgoing (discharged) power back into AC for use in the home

In an AC-coupled system, DC power from the solar panels is sent to the inverter for conversion.
All energy flows after that are in the form of AC power.

The Tesla Powerwall 2 and the sonnen eco — the two most popular solar battery solutions — use this AC-coupling method because it allows easy retrofitting to existing grid-tied solar systems.

Pro of AC-coupled battery: can be added to any grid-tied system without needing to change the existing setup and grid-tied inverter.

Con of AC-coupled battery: multiple conversions of power from DC to AC (and vice versa) results in higher efficiency losses.

DC-coupled batteries

This coupling method requires a charge controller to regulate the flow of DC power into the battery. A battery inverter is also needed to convert DC power flowing out of the battery into AC power so it can be used in the home. This is the coupling method used for traditional off-grid solar power systems.

Some market-leading DC coupled solutions, such as the StorEdge solution from SolarEdge, incorporate a charge controller into the battery inverter. Paired with a battery, such as the LG Chem RESU, this allows them to offer an all-in-one home energy storage solution similar to the AC-coupled Tesla Powerwall and sonnen eco.

In a DC-coupled system, the inverter uses DC power from the solar panels to charge the DC battery.

Pro of DC-coupled batteries: lower power losses as there are fewer power inversions.

Con of DC-coupled batteries: to retrofit to existing grid-tied systems the grid tied inverter has to be compatible with the battery inverter.

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