Best Batteries for Solar Power Storage

Capturing sunlight is only half the battle of utilizing solar energy. Effective energy storage solutions are essential to maximizing the benefits of solar power and eliminating dependence on the electric grid. 

When you add battery storage to your PV system, you can capture any solar energy you can’t use immediately and store it for later use, such as when the sun goes down or on a cloudy day.

Below, learn the ins and outs of solar batteries, their benefits, and how to choose the best ones for your needs.

How Do Solar Batteries Work?

Solar batteries are essential to any solar power system, especially whole-home backup systems. Solar batteries are connected to PV panels such as EcoFlow Rigid Solar Panels, usually fixed on the roof, capturing sunlight. The sunlight is then converted into DC (Direct Current) electricity. This electricity can be used immediately (by using an inverter to change it to Alternating Current, or AC, electricity) or stored for later use. 

Let’s say you need power, and your EcoFlow 400W Rigid Solar Panels aren’t actively collecting sunlight, like at night or on cloudy days. In this case, the stored energy is converted back into AC electricity through an inverter. This AC power can run your home appliances and devices, ensuring a continuous power supply even when the sun isn’t shining.

What are the Different Types of Battery Chemistries?

The two most common types of solar batteries are lithium-ion batteries and lithium-iron-phosphate (LFP) batteries. Learn more about what each option offers to determine which will perform the best and meet your needs.

Lithium-ion

Lithium-ion batteries are popular for solar power storage because they’re highly affordable and offer a high energy density. These batteries can store more energy than lead-acid batteries of the same size, making them a compact and efficient option. 

Lithium-ion batteries are also less affected by maintaining a high state of charge, a common requirement for backup systems. They’ll be a reliable battery source even after many years of daily use.

Another great thing about the lithium-ion battery chemistry is its minimal maintenance needs. Once installed, they require little to no care, saving you time and money while granting you peace of mind. They’re also designed to be user-friendly, which is helpful if you’re not a technical expert but prefer to do things yourself. 

Lithium-ion batteries can withstand daily charging and discharging cycles without significant wear and tear. It makes them ideal for homeowners looking for a low-maintenance, high-efficiency battery solution.

Lithium Iron Phosphate (LFP)

Lithium Iron Phosphate (LFP or LiFePO4) batteries are a newer solution on the market that has become rapidly popular due to their longevity and durability. Compared to traditional lithium-ion batteries, they offer a greater depth of discharge, meaning they can be depleted more before needing a recharge. 

LFP batteries, such as the ones used in EcoFlow Solar Generators, are an excellent choice for daily cycling applications, where the battery is charged and discharged daily.

LFP batteries can withstand a wide range of temperatures and have little to no risk of thermal runaway, making them a safer option. Thermal runaway happens when the temperature increases and causes the battery cell to raise its temperature further, leading to a small explosion or fire. 

Standard Lithium batteries carry a risk of thermal runaway, so the LFP battery’s enhanced resistance to this kind of reaction makes them a popular choice due to their increased safety, especially for residential use.

They’re particularly well-suited for self-consumption mode, where the battery charges from solar power and discharges only when required to meet household demand when the PV panels aren’t generating enough energy on their own. 

In self-consumption mode, the battery usually carries a low charge at night, and LFP batteries prefer this setting, making them ideal for backup storage.

Pros and Cons of Solar Batteries

Solar batteries give your home solar power system huge advantages, such as lower energy bills, reduced grid dependence, and, of course, positive impacts on the environment. However, they’re not without a few cons. Learn more about the benefits and drawbacks of these batteries to determine whether the investment is worth it to you.

Pros

• Reduced Energy Bills: Storing and using all excess solar energy can significantly reduce your dependence on the grid, leading to lower energy bills. You’ll be able to take advantage of all the solar energy your system is already capturing, benefiting from a more efficient system.
• Good for the Environment: Solar batteries rely on renewable energy, effectively reducing carbon emissions. Unlike other generators, such as gas or diesel generators, they don’t release toxic fumes or greenhouse gases.
• Long Lifespan: High-quality solar batteries can last many years, providing a reliable power source. Batteries using lithium-ion or LFP chemistries offer exceptionally long lifespans.
• Reduce Dependence on Grid: With a solar battery, you can rely less on the grid and more on your renewable energy source. Rather than sending back any excess energy you produce to the grid, you can utilize it and make their involvement obsolete.
• Low Maintenance: Most solar batteries require minimal maintenance, making them a hassle-free addition to your PV system. Once installed, they don’t need refueling or regular cleaning.
• Noiseless: Unlike noisy gas, propane, or diesel generators, solar batteries are silent, making them perfect for residential use. It also means you can use them at night, even during camping trips, without disturbing your peaceful sleep.
• Can Work Alongside Grid-Tied System: Want to keep your grid-tied system? No worries! Solar batteries can be integrated with grid-tied systems, providing a seamless energy solution and expanding your power options.
• Expandable Capacity: Certain models can be used in parallel to expand their capacity. The EcoFlow DELTA Pro ULTRA is a powerful option and a great example of this. It can efficiently serve as a whole-home backup solution, thanks to its potential 21kW output and 90kWh capacity when used with up to 3 inverters and 15 batteries.

Cons

• High Upfront Cost: The initial investment for solar batteries can be high, but the long-term savings often justify the cost. If you can’t comfortably afford the equipment costs, it could be a significant deterrent to investing in a battery backup.
• Can Be Bulky: Some solar batteries can be large and require significant installation space. Smaller options with lower storage capacity and output are available, but they may not be able to run all of a home’s appliances.

Choosing the Best Batteries for Solar Power Storage Capacity

Ensure you’re making the right choice for a solar battery. Here’s what to remember as you consider the options and find the best fit for you, your family, and your power needs.

Output

The amount of power the battery can deliver at any given time is an important consideration. It’s usually measured in kilowatts (kW) and varies depending on the type of battery. Some may have a higher output capacity, making them better suited for larger homes or businesses with high energy needs. Add up the kW of all your essential appliances and ensure this is within the output of the solar battery you’re considering purchasing to avoid overload.

Capacity

The capacity of the battery is different than its output; it’s the total amount of energy it can store at one time. It’s typically measured in kilowatt-hours (kWh). If you have high energy demands or plan to run multiple appliances simultaneously for a long time, choosing a battery with a higher capacity will be more beneficial.

Depth of Discharge

How much of the battery’s capacity can be used before recharging? This is known as the depth of discharge (DoD) and varies among different types of batteries. A higher DoD means you can use more of the stored energy before needing to recharge, while a lower DoD may require more frequent and timely recharging.

Round-Trip Efficiency

A battery’s round-trip efficiency measures how much energy can be used from a full charge compared to the amount needed to recharge it. For example, if a battery has a 90% round-trip efficiency, that means for every 90 kilowatt-hours used, 100 kilowatt-hours are required to fully recharge it. The higher a battery’s round-trip efficiency, the more economical it is.

Battery Lifespan

The battery’s lifespan describes the number of charge/discharge cycles it can undergo before it starts degrading. Solar batteries may be used frequently, even daily, so a long lifespan is essential.

Average Cost

Consider the upfront cost of the battery itself and any additional installation or maintenance costs. If you don’t already have solar panels, an inverter, and the other components of a PV system, you may need to invest in a complete solar generator such as the EcoFlow DELTA Series Solar Generators.

Frequently Asked Questions

Final Thoughts

Solar batteries store excess energy, allowing you to optimize your home’s solar power use and ensure a continuous power supply. Integrating the correct solar battery into your energy system will enable you to enjoy the full benefits of renewable energy while keeping the planet a little cleaner and greener.

When choosing a battery for storage, consider capacity, lifespan, and cost to find the best fit for your needs. Ready to take the next step? Explore EcoFlow’s DELTA Solar Generators for reliable and efficient solar power storage solutions.