September 24, 2024

Types of solar batteries: A guide to solar energy storage

Types of solar batteries

Solar batteries play a pivotal role in the world of renewable energy.

When the sun goes down each night or when weather conditions limit available sunlight, a solar battery can enable sustainable renewable energy use at home and keep your power on during local power outages.

If you’re thinking about going solar or already have panels installed, a solar battery can help you achieve further energy independence with greater control over your renewable power consumption, for the lowest possible ongoing electricity costs and associated carbon emissions.

In this article, we outline the most common types of solar batteries and walk through everything you need to know to make the best energy storage decisions for your home or property.

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Types of solar batteries used today

Today, most homes and businesses use lithium-ion solar battery technology to store energy safely and efficiently on-site. Although there are several other types of solar battery chemistries available today, the best overall storage solution for a home will almost always be a lithium-ion-based system.

 Lead-acid batteriesLithium-ion batteriesFlow batteries
TechnologiesFlooded or sealed; AGM (Absorbed Glass Mat), Gel (Gelled Electrolytes)Lithium iron phosphate (LFP or LiFePO4), nickel manganese cobalt (NMC), and moreRedox, hybrid, and membraneless; saltwater, iron, and more
AboutThe oldest and cheapest storage technology, such as batteries in combustion engine vehiclesThe most common type of solar batteries in homes, with superior energy density, safety, efficiency, availability, and lifespanAn emerging, eco-friendly technology that stores electricity within a liquid chemical solution
ApplicationsSmall DIY solar installations with a tight budgetIdeal for residential and commercial solar energy storageBest for large-scale energy installations when available
SafetyGenerally safe, but may become hazardous if handled incorrectlyThe safest home solar battery technology, with built-in thermal management featuresSafe performance with ongoing monitoring, low fire-risk
MaintenanceOften requires regular maintenance and upkeepMinimal maintenance required outside of routine inspectionsMay require ongoing maintenance for optimal efficiency
PerformanceModerate efficiencies, slow charging, and low depth of discharge (50% to 80%)High efficiencies, fast charging, and high depth of discharge (80% to 98%)High efficiencies, rapid recharging, and up to 100% depth of discharge
LifespanShort (3 to 7 years), depending on the technology and upkeepMedium to long (5 to 20 years), depending on battery chemistry and qualityLong (20 to 30+ years), with few tested examples
Energy density, size, and weightLow-density, bulky, and heavyDense, compact, and relatively lightweightLow-density, with large tanks required

While lead-acid batteries may be the technology of yesterday and flow batteries could be the future of large-scale electricity storage, lithium-ion batteries are the best choice for homeowners going solar today. Although lithium-ion batteries may cost more than lead-acid alternatives upfront, they are generally better investments with increased efficiency, greater storage capacity, longer lifespans, and the potential to qualify for solar tax incentives and other clean energy programs.

Factors to consider when choosing a solar battery

Within the realm of lithium-ion solar batteries, there are many different products available currently with various capabilities, price points, and intended uses. While this article explores permanently installed solar energy storage for homes, lithium-ion solar batteries are also typically used in portable energy systems.

Home solar battery capacity and quantity

A solar battery’s capacity determines how much energy can be stored and used in your home or exported to the electricity grid. Although prices naturally rise with increased storage capacity, larger battery systems can also be more valuable in offsetting all or most of your utility electricity expenses.

If sustained power during local outages is your primary motivation for a solar battery, rather than total energy independence, then you may not necessarily need to install a large backup reserve. Instead, you could opt for a smaller capacity, lower-cost system designed to exclusively run your property’s essentials.

Today, most solar batteries can be “stacked,” so that you can find the optimal storage capacity to meet your energy goals and budget. Just as solar microinverters make it easy to add solar panels later in the life of your home energy system, it may also be possible to incorporate additional solar batteries after an initial storage installation.

Solar battery size and installation requirements

When choosing your home solar battery, you may find that various products have differing installation guidelines or requirements. Provided there’s enough space on your property, most high-quality lithium-ion solar batteries can be mounted onto the wall indoors or outdoors and are typically found in garages, utility rooms, and other non-living spaces.

AC-coupled vs. DC-coupled battery

Lithium-ion solar batteries may be AC- or DC-coupled, depending on the design of your energy system. While DC-coupled battery systems may be slightly more efficient, neither technology is explicitly better. In general, AC-coupled batteries are considered easier to install or replace on an existing system and allow you to store electricity from your solar panels or the energy grid.

AC-coupled battery systems

DC-coupled battery systemsWhen designing your home solar power system, it’s important to talk to your installer about plausible storage options and whether an AC- or DC-coupled solar battery will make more sense for your installation.

Solar battery efficiency and features

While all solar batteries are built to store and discharge renewable energy, a system’s “round-trip efficiency” represents how well it can do so. Beyond efficiency alone, many of today’s top solar batteries also include special operating features to optimize your home’s electricity generation and consumption.

Typically controlled with an app or on the hardware itself, advanced solar batteries include several operating modes to automatically minimize your ongoing electricity costs or leave the lowest possible carbon footprint while remaining prepared for local power outages.

Warranty and expected lifespan

Finally, a solar battery’s warranty coverage is the best way to guarantee your energy independence and ensure your investment in electricity storage will be worth it. Along with the included warranty period, a solar battery may be more likely to perform for its expected lifespan when purchased from a reputable brand, rather than a riskier, cheaper alternative.

Key takeaways and designing your solar battery system

In short, there are several different types of solar batteries, but lithium-ion systems are the most common and best overall technology for residential use today.

With a highly efficient and advanced lithium-ion solar battery, you can increase the capabilities of your renewable power system, which, in turn, leads to reductions in home energy bills and your property’s carbon footprint.

Built for safety, efficiency, and reliability, Enphase IQ Batteries can help you reach your energy goals. Tested to rigorous safety standards above market requirements, Enphase IQ Batteries include an industry-leading 15-year limited warranty and offer full control of your solar power and ongoing electricity expenses with the Enphase App.

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