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How do solar batteries work?

Your home’s energy consumption varies a lot during the day, so some of your solar energy usually ends up going unused by you. Solar batteries store the electricity produced by your rooftop solar panels so that you can use it at other times. This adds valuable flexibility to your solar system, allowing you to use your stored solar energy during grid outages, when grid electricity is more expensive, or simply when the sun isn’t shining.

Enphase Encharge™ storage systems

  • Encharge 3™ storage system

    Encharge 3™ storage system

    The Encharge 3™ all-in-one AC-coupled storage system provides a total usable energy capacity of 3.4kWh and four embedded grid-forming microinverters. It provides great flexibility in starting small and adding incremental capacity.

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  • Encharge 10™ storage system

    Encharge 10™ storage system

    The Encharge 10™ all-in-one AC-coupled storage system, comprised of three base Encharge 3™ storage units, provides a total usable energy capacity of 10.1kWh and twelve embedded grid-forming microinverters. Connect multiple Encharge 10 storage systems to maximize backup potential for whole home backup.

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Battery technology

  • What are the various types of solar batteries available?

    Lithium-ion is the most popular solar back up battery type for home storage systems. Lithium-ion has many advantages: it has high roundtrip efficiency, superior energy density, and a lifespan of at least 10 years.

    The two most common chemistries of lithium-ion batteries are Lithium Iron Phosphate (LFP) and Nickel Manganese Cobalt (NMC). While NMC batteries have slightly higher energy density than LFPs, they have a relatively higher risk of thermal runaway, which can lead to fire and even explosion if punctured. LFPs are safer than NMCs because they stay cooler, eliminating the risk of thermal runaway fires.

  • What are the benefits of a battery combined with solar?

    There are many ways solar plus energy storage can be valuable for your home:

    • Reduce your utility bill: When you charge your solar panel battery from your solar panels, you reduce the amount of electricity you buy from the grid. You can also save money by using the energy stored in your solar battery when utility rates are high. A smart energy storage system, like Enphase’s Encharge™ energy storage unit, does all of this automatically for you.
    • Backup power/Back up Battery: When the power goes out, your backup battery will provide power for your home’s critical devices.
    • Maximize your solar panels: Your solar panels will sometimes produce more energy than your family can consume at that moment. Solar batteries allow you to store that energy to use another time.
  • What’s the difference between a solar battery and a generator?

    A generator is a backup system that is typically powered by fuels such as diesel, gasoline, natural gas, or liquid propane. Generators can normally run continuously for anywhere between 7 and 12 hours at 50% power.

    A solar panel battery charges from your rooftop solar panels. Depending on the back up battery and solar system size and your electricity demand, a solar back up battery can power your family’s critical devices for up to 24 hours and beyond. Read more about differences between solar battery and generator.

  • How do solar and storage work best together?

    Solar and storage systems work best together when they have a cohesive process for communication and functioning as a whole unit. Some systems piece together solar and storage from different manufacturers. While systems like this can still function, the varied parts often mean inconsistencies in warranties, software, and support – and as a result, lower performance.

    Enphase offers an all-in-one solar and storage system, integrating all components on a single software platform. This means a uniquely versatile system with universal communication and optimized functionality.

Choosing your storage system

  • How do I choose the best solar battery for my needs?

    When looking for the best deep cycle battery for your home’s needs, you’ll want to consider a number of key factors:

    • Battery type: The most common solar battery types are lithium-ion and lead acid. Among lithium-ion batteries, you will also want to consider Lithium Iron Phosphate (LFP) versus Nickel Manganese Cobalt (NMC) to ensure the safest operation.
    • Battery capacity and power: How much energy do you want your solar back up battery to store? Are you powering a few critical loads or your entire home? This will impact how many storage units you need. You can actually combine multiple Encharge units to suit your needs.
    • Battery application: Backup power and reducing electricity costs are two of the top reasons that people purchase solar batteries.

    Find out what kind of system is best for you

    Try the Enphase system estimator

  • Can I install a home solar battery if I don’t have rooftop solar?

    Yes, home energy storage systems can provide benefits to homeowners even when not paired with a rooftop solar system. Your solar battery would simply store energy drawn from the grid instead of solar panels. This can still provide cost advantages by reducing your utility electricity demand during high rate periods while offering backup power during grid outages.

Battery reliability and safety

  • What happens if a solar battery unit fails?

    Most solar and storage systems are set up with a single string inverter that passes the energy from the solar battery unit and solar system to your home. If this inverter fails, the whole system is unable to function correctly. And if you can’t rely on your backup system, it becomes useless.

    So, Enphase created a unique design that backs up your backup system: multiple microinverters placed in the energy storage unit. This means that if one microinverter malfunctions, the other microinverters ensure that the system continues to run smoothly.

  • What is a battery’s depth of discharge?

    Depth of discharge (DoD) refers to the percentage of a battery’s capacity that has been discharged from the battery. For example, a battery that is completely empty of charge has a DoD of 100%.

    Battery providers specify a maximum DoD for a specific battery in order for it to retain its effectiveness. When looking for a home storage unit, you will ideally want to find one with a higher DoD. This means that it will require less frequent charging compared to a battery with a lower DoD.

  • What is round trip efficiency?

    All solar batteries lose some percentage of their energy in the process of charging and discharging. Round trip efficiency (RTE) refers to the amount of energy that a solar power battery can dispatch compared to the amount of energy that it can store. For example, a battery for solar with an RTE of 70% can discharge 70% of the energy that it stores. When looking for a battery for solar, you will ideally want one with a higher RTE in order minimize the amount of energy lost when your battery cycles.

  • How long do solar batteries last?

    Depending on the chemistry, solar batteries can last anywhere between 5 and 15 years or even longer. Most solar power batteries are warrantied up to 10 years with a performance guarantee. This means that if your system isn’t performing as promised at the end of its warranty, your battery provider will typically replace it free of charge. You can learn more about home battery warranties here.

    Battery lifetime also depends on how often you use it; the more frequently it cycles, the more quickly the battery will degrade.

  • Are home solar batteries safe?

    While all solar battery types have some safety risks, strict regulations and safety procedures are in place to ensure that solar power batteries are safe for home use. Solar power batteries that utilize Lithium Iron Phosphate (LFP) chemistry, like Encharge, are among the safest available for residential homes.

Learn more about solar batteries

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