Choosing the Best Battery Backup for Your Home
Harnessing the sun’s power through solar panels is a great way to ensure your long-term energy security and environmental well-being — but what happens when the sun sets?
That’s where solar batteries come in. Buying a solar battery for your solar system is essential if you want to maximize your solar investment, save money, and achieve true energy independence.
But with so many solar battery options on the market, it can be tough to know where to start. Let’s go over some of the basics of solar batteries, as well as some of the top solar battery options on the market so you can find the perfect one for your home and energy needs.
Why Go Solar?
While solar panels generate clean energy when the sun is out, their output naturally decreases as the sun sets. Batteries bridge this gap, storing excess solar power during the day for use at night or during peak demand times. This empowers you with:
- Energy Independence: With solar batteries, you can generate and store your own electricity, reducing your dependence on utility companies and fluctuating rates.
- Resilience in Outages: If your area is prone to outages or you simply like to be prepared, solar batteries provide reliable backup power to keep your essential appliances running.
- Reduced Carbon Footprint: By storing and utilizing solar energy, you’re decreasing your reliance on harmful fossil fuels.
- Cost Savings: Over time, solar batteries can help offset your electricity costs and can even make you eligible for government incentives and rebates.
Things to Consider Before Buying a Solar Battery
Capacity
It’s important to determine how much energy you will need to store in order to keep the lights on during outages and to power essential appliances when the sun isn’t out. To calculate your desired storage capacity — measured in kilowatt-hours (kWh) — you need to consider your:
- Average daily energy usage: Track your electricity consumption for a few weeks to understand your baseline needs.
- Appliance wattage: Identify high-demand appliances like air conditioners and ovens to estimate peak power draw.
- Backup duration: Determine how long you want to be able to power essentials during an outage. A few hours versus the entire night may change the type of battery you need.
Warranty
Your battery’s warranty guarantees its quality and performance for a set period. Longer and more comprehensive warranties usually come with a higher price tag, so find a balance that suits your budget and risk tolerance. Look for:
- Minimum duration: Most solar battery warranties run for around 10-15 years.
- Performance warranty: This ensures the battery delivers its rated power output over time. Look for warranties that guarantee 70% or higher output.
Efficiency
The higher the efficiency of your battery, the less energy gets wasted during charging and discharging. This translates to cost savings and longer battery life. Remember, even small efficiency gains can significantly impact your long-term savings. When comparing batteries, look at:
- Round-Trip Efficiency: This measures the energy loss during charging and discharging cycles. Higher efficiency translates to more usable energy from your stored sunlight. Look for batteries with high efficiency (85% or above) to maximize your energy savings.
- Depth of Discharge (DoD): This is the percentage of the battery’s capacity that can be safely used. Higher DoD allows for deeper discharge during outages.
Compatibility
If you have an existing solar system, your battery needs to work seamlessly with your existing solar inverter and other system components. Incompatibility can lead to headaches and potentially void warranties. Make sure your battery is compatible with your system’s:
- Voltage and amperage: Ensure the battery’s voltage and amperage match your system’s requirements since mismatches can damage equipment.
- Communication protocols: Different batteries use different communication protocols to “talk” to your inverter. Make sure to research what your current system uses and that the battery you want is compatible.
Price
The biggest factor when choosing a solar battery often comes down to cost. Solar batteries can be significant investments.
Be sure to consider:
- Incentives: Many Americans who purchase solar energy storage are eligible for the federal Investment Tax Credit that pays you back up to 30% of the cost of installing a solar energy system, and some qualify for the Self Generation Incentive Program (SGIP), which offers rebates for solar energy storage purchases and installation for up to 100%.
- Upfront cost: Battery prices vary depending on brand, capacity and features.
- Installation costs: Professional installation adds to the initial expense. DIY options may be available for specific batteries, but they are not recommended due to the expertise needed.
- Payback period: Calculate how long it will take for energy savings and potential electricity bill reductions to offset your initial investment.
- Brand reputation: Choose a reputable solar battery installer with a proven track record of successful solar and battery installations and satisfied customers.
Best Batteries for Solar Power Storage
Tesla Powerwall 3
The Tesla Powerwall 3 boasts impressive performance and a household name behind it. With 13.5 kWh of usable energy, it can power a typical home for hours, and its 10-year warranty offers peace of mind and unlimited charging and cycles. Tesla Powerwall batteries earn high marks for technology innovation, reliability, and intelligent connectivity within their ecosystems.
Pros:
- One of the best warranties available with no limit on the number of cycles which means you can discharge and recharge the battery an endless number of times and still get a repair or replacement under warranty. This warranty is only available if you purchase the Powerwall from a Tesla-approved installer.
- Roundtrip efficiency of 89%: Tesla Powerwall 3 is very efficient at converting incoming electricity into stored electricity and back into usable electricity.
- Impressive continuous power supply of 11.5 kWh. This robust output ensures your home can run most appliances as usual during an outage.
- Sleek design: Its streamlined and modern design blends seamlessly into the home, making it ideal for those looking for an aesthetic option.
- Strong reliability & performance reputation from Tesla’s proven expertise.
Cons:
- Installation: Requires Tesla-certified professionals.
- Slightly shorter warranty (10 years) compared to Enphase and Franklin.
Franklin Whole Home Battery
Franklin battery is composed of lithium iron phosphate (LFP), like the Tesla Powerwall 3. The advantages of LFP include better lifespan, safety, and tolerance for extreme temperatures. LFP batteries generally are able to give 20 good years of life.
Pros:
- High capacity and power: This ensures power back-up for everything, including air conditioning, even during extended outages.
- Fast charging: This compact battery is fast-charging and has 100% DOD.
- Great for home use: Franklin Whole Home batteries are the least prone to thermal runaways compared to all other battery types.
- Ethical advantage: These batteries don’t need cobalt to function, unlike many other solar batteries.
- Long lifespan: Franklin Whole Home batteries can last five times longer than Li-ion batteries.
- High tolerance for extreme temperatures: These batteries can also effectively operate in a wide range of temperatures and weather conditions.
- Long warranty: The Franklin system comes with a 12-year warranty.
Cons:
- Slightly weaker continuous output (5 kW) compared to the Tesla Powerwall 3.
Enphase IQ Battery 5P
Enphase IQ 5P comes with an industry-leading warranty, microinverters on each panel, and the ability to track each panel individually. Its small size of 5 kWh modularity makes it versatile and scalable. You can use a single module for small-scale self-consumption or stack up several batteries to create a large backup system.
Pros:
- Industry-leading warranty length: Enphase IQ 5P guarantees an industry-leading warranty of 15 years.
- Integrated microinverter technology: This technology works frictionlessly with solar panels.
- High quality and reliable: With a DoD of 100%, Enphase IQ 5P is known for its high-quality batteries and high safety standards, which provide peace of mind during use and extended outages.
- Manage your whole energy system with just one app: Enphase’s app provides visibility and control of every solar panel and device in your Enphase Energy System.
- Enphase IQ 5P could be advantageous when paired with small systems as a grid-tied battery solution. For someone with a 4 to 6 kW system, one grid-tied 5P is likely the most cost-effective way to get a battery and maximize savings under NEM3.
Cons:
- Not compatible with many of Enphase’s second-generation batteries, such as the 10T and IQ 3T.
Frequently Asked Questions
Do solar batteries depreciate?
Like most electronics, solar batteries depreciate over time.
How long do solar batteries last?
Solar batteries typically have a lifespan of 10-15 years, but some can last up to 20 years, depending on the quality of the battery and operating procedures.
Do solar batteries impact solar panel depreciation?
While batteries can increase your initial investment, they can also extend the life of your solar panels by reducing their workload during peak demand times. This can potentially offset solar panel depreciation.
Do solar batteries increase the value of my home?
While the impact varies, the rising interest in eco-friendly homes can make your property more appealing to buyers looking for sustainable systems.
Do solar panels have batteries?
While solar panels generate electricity, they don't store it. You need separate solar batteries to store excess solar energy.
What type of battery backups do solar systems use?
Lithium-ion batteries are the most popular choice due to their high efficiency and long lifespan.
Additional Resources
Contact the Experts Today
Investing in solar batteries is an investment in your long-term energy security and environmental well-being. With careful planning and the right battery solution, you can unlock the full potential of your solar panels and enjoy the benefits of self-reliance for years to come.
Consult with one of our qualified solar installers today. We’ll assess your energy needs and recommend the best solar battery solution for your home.