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Writer's pictureAustin Brentley

Solar Battery Vs. Generators for Backup Power

solar battery backup

When the grid experiences a massive power outage, it can create dangerous conditions for everyone in the area. Home and business owners looking for more reliable power even during an outage might consider diesel—or propane-powered generators or installing a PV system with solar battery backup.


As an installer, it’s important to know the pros and cons of a solar battery vs generator in terms of necessary equipment, cost, reliability, capacity, and more. We’ll explore the difference between a solar battery backup vs a generator and highlight some of the top performers in both categories on the market today.


Solar Vs. Generator

When considering solar battery vs. generator solutions, it’s crucial to understand the key differences. A solar battery stores energy produced by solar panels, providing clean, renewable power during outages, while generators rely on fossil fuels to generate electricity. Installers can help clients assess their energy needs and guide them toward the best solution.


Both options require a significant investment, so discussing the solar vs. generator payback period and total costs is essential. In this comparison, we’ll explore the pros and cons of each, helping you choose the most practical option for your clients.


Solar Battery Backup

Solar systems with battery storage allow clients to store excess energy generated during the day for use at night or during power outages. Solar batteries store energy produced by a solar installation, ensuring a reliable power supply even when the sun isn’t shining.


However, not all batteries are built for grid connectivity and may only be suitable for completely off-grid systems. Installers can evaluate a client’s energy needs and savings goals to recommend the best setup.


Here are common options for solar battery backup:

  • Off-grid DC-coupled batteries: These are often used for remote properties or recreational vehicles. They typically come with built-in inverters to convert direct current (DC) to alternating current (AC).

  • Off-grid AC-coupled batteries: These work similarly to DC-coupled batteries but convert the energy before it reaches the batteries.

  • Grid-tied AC-coupled batteries: Popular for residential use, these systems come with built-in inverters, making them ideal for both new installations and retrofits. Grid-tied setups require solar permitting and utility approvals.

  • Grid-tied DC-coupled solar batteries: These batteries can handle high-voltage loads and are compact, making them a preferred option for homeowners.


A key factor in battery selection is the depth of discharge (DoD), which measures how much power can be drawn relative to the battery's total storage capacity. A DoD of 75%, for example, means that 7.5 kWh can be used from a 10 kWh battery. Higher DoDs, typically 95% or above, are ideal for maximizing energy storage efficiency and optimizing the performance of solar battery backup vs generators. Choosing batteries with higher DoDs ensures better energy utilization, making them a more efficient option for solar storage systems.


For optimal performance, aim for batteries with high DoD for better energy storage and utilization.


Pros of a Generator vs Solar Battery

When comparing solar vs generator backup solutions, there are several pros to using a generator over a solar battery:


  • Lower Upfront Costs: Generators generally cost less upfront than solar battery systems, especially for higher-capacity power needs.

  • Power Output: Generators can deliver higher continuous power output, making them suitable for heavy loads like central HVAC systems or large appliances during an outage.

  • Fuel Accessibility: Generators run on readily available fuels like gasoline, diesel, or natural gas, which can provide a more reliable power source in areas with limited sunlight. For those needing versatile backup power, mobile diesel generators offer a dependable and portable solution for various energy requirements.

  • 24/7 Power: Unlike solar batteries, generators can provide continuous power as long as fuel is available, making them a dependable solution during extended outages or low-sunlight periods.


Cons of Generators vs Solar

While generators offer some benefits, there are significant drawbacks when compared to solar batteries in the solar vs generator discussion:


  • Environmental Impact: Generators rely on fossil fuels, releasing CO2 and other harmful greenhouse gases during operation.

  • Safety Concerns: Improper use of generators can lead to carbon monoxide poisoning, electrical hazards, and fire risks.

  • Noise and Odor Pollution: Generators are noisy and emit unpleasant fumes, contributing to both air and noise pollution.

  • Limited Use: Generators typically sit idle for most of the year, being used only during blackouts. This limited use may feel like a poor investment for homeowners.

  • Maintenance: Generators require ongoing maintenance, including servicing, fuel storage, and regular refueling.

  • No Long-Term Savings: Unlike solar batteries, which recharge with free sunlight, generators require constant refueling, leading to ongoing costs. Over time, solar battery systems tend to provide better long-term savings by using renewable energy.


solar battery vs generator

When Solar Batteries Better Than Generators

In the ongoing debate of a solar battery vs generator, there are several scenarios where solar batteries may be the superior choice for homeowners.


Here are some key situations in which solar batteries excel:

  1. Sustainable Energy Use: Solar batteries store energy generated from solar panels, allowing homeowners to use clean, renewable energy. This reduces reliance on fossil fuels and lowers carbon emissions, making it a more environmentally friendly option when considering solar vs a generator.

  2. Energy Independence: Solar batteries can provide power during outages, giving homeowners autonomy over their energy supply. This is particularly valuable in areas prone to frequent blackouts or for remote properties that lack grid access.

  3. Lower Operating Costs: Solar batteries can significantly reduce energy costs after the initial investment. They utilize free energy from the sun, while generators require fuel, leading to ongoing expenses for homeowners.

  4. Quiet Operation: Unlike generators, which can be noisy, solar batteries operate silently. This makes them an ideal choice for residential areas where noise pollution can be an issue.

  5. Less Maintenance: Solar battery systems typically require less maintenance than generators. Generators need regular servicing, oil changes, and fuel refills, whereas solar batteries are largely maintenance-free, aside from periodic monitoring.

  6. Incentives and Rebates: Many regions offer tax credits, rebates, and incentives for solar battery installations, making them financially attractive. Generators usually do not qualify for such incentives, impacting their overall cost-effectiveness.

  7. Aesthetic Integration: Solar battery systems can be installed discreetly alongside solar panels, preserving the aesthetic of a property. Generators, on the other hand, may take up more space and disrupt landscaping.


When Are Generators Better Than Solar Panels?

In the solar vs generator debate, there are certain scenarios where generators may be a more suitable option for homeowners.


Here are some key situations in which generators excel:

  • Instant Power Availability: Generators provide immediate power during an outage, ensuring that essential appliances and systems function without delay. Unlike solar batteries, which require time to recharge, generators can supply electricity as soon as they are activated.

  • High Energy Demand: For households with significant energy requirements, such as multiple HVAC systems or large appliances, generators can supply more power on demand compared to solar batteries. This makes them ideal for heavy-duty usage, such as during extreme weather conditions.

  • Lower Initial Investment: While solar panel systems and batteries can be expensive to install, generators often have a lower upfront cost. This can make them more accessible for homeowners who need immediate power solutions without a significant financial commitment.

  • Less Dependence on Sunlight: Generators do not rely on sunlight to operate, making them a reliable choice during extended periods of cloudy weather or in regions with limited sunlight. In contrast, solar panels' effectiveness can diminish in adverse weather conditions.

  • Fuel Versatility: Many generators can run on various fuels, including gasoline, propane, and natural gas. This flexibility allows homeowners to choose a fuel source that best suits their needs and availability, unlike solar panels, which depend on sunlight.

  • Simplicity of Use: Generators are often straightforward to operate, requiring minimal setup. For homeowners who may not want to deal with the complexities of solar installation and maintenance, generators present a simpler alternative when considering solar power vs a generator.


Combining Solar Batteries and Generators

Combining solar batteries and generators provides a robust energy solution for homeowners who aim for reliability and sustainability. This hybrid setup allows users to utilize renewable solar energy while also having a backup generator for consistent power during extended outages or low solar production periods.


The integration of these systems enables homeowners to lessen their dependence on fossil fuels, decrease energy expenses, and improve energy independence. However, evaluating the initial investment and ongoing maintenance needs of both solar and generator systems is crucial to determining the best fit for your energy requirements. Ultimately, understanding the trade-offs in the solar battery vs. generator debate can help you make an informed decision that aligns with your goals.


Here are some key benefits and considerations for combining these systems:

  • Reliable Backup Power: By pairing solar batteries with generators, homeowners can ensure a continuous power supply during outages. Solar batteries store energy generated during sunny days, while generators can kick in during prolonged outages or when battery reserves run low. This dual approach ensures that critical appliances remain powered.

  • Enhanced Energy Independence: Combining these systems allows homeowners to rely less on the grid. Solar panels generate renewable energy, reducing electricity bills, while batteries store that energy for use at night or during cloudy weather. The generator serves as a backup, providing additional energy security when solar generation is insufficient.

  • Cost Efficiency: While solar panels and batteries require a significant initial investment, they can lead to long-term savings. Generators can be used as a temporary solution during outages, preventing the need to purchase additional battery capacity. This hybrid approach can help homeowners maximize their return on investment.

  • Flexibility and Customization: Homeowners can tailor their energy systems to meet their specific needs. For instance, they might choose a smaller battery system for everyday use and rely on a generator for backup during emergencies. This flexibility allows for better energy management and optimization.

  • Reduced Carbon Footprint: Using solar power reduces dependence on fossil fuels, while generators can be used sparingly, primarily during emergencies. This combination can significantly lower greenhouse gas emissions compared to relying solely on a generator for backup power.

  • Simplified Maintenance and Monitoring: Integrating both systems can provide homeowners with more robust monitoring solutions. Smart technology can track energy usage, battery levels, and generator performance, ensuring optimal operation and maintenance.


However, there are drawbacks to combining generators and solar batteries in the solar vs generator discussion, including:

  • Initial Costs: The combined setup may require a higher upfront investment. Homeowners should evaluate their energy needs and potential savings to determine if the investment is worthwhile.

  • Space Requirements: Both systems require space for installation, which may be a consideration for homeowners with limited outdoor areas.

  • Fuel Dependence: While solar energy is renewable, generators may require fuel, which could lead to costs and logistical concerns during extended outages.


Home Generator Vs. Backup Generator

A whole home generator and a portable generator serve different purposes and have distinct characteristics. These are important considerations when comparing solar vs generators.


Home Generator

  • Purpose: Designed for whole-home backup during power outages, providing continuous electricity to essential appliances and systems.

  • Fuel Source: Typically runs on natural gas, propane, or diesel and is often connected directly to the home's utility lines.

  • Installation: Permanently installed on or near the property and wired into the home's electrical system.

  • Capacity: Higher capacity to support the entire home's electrical needs.

  • Automation: Equipped with an automatic transfer switch to start automatically when grid power fails.


generator vs solar panels

Portable Backup Generator

  • Purpose: Offers temporary and mobile power for various applications, such as camping, outdoor events, or providing backup for specific appliances.

  • Fuel Source: Runs on gasoline, propane, or diesel and requires manual refueling.

  • Installation: Portable and can be moved to different locations as needed; no permanent installation is required.

  • Capacity: Limited capacity suitable for running specific appliances or devices.

  • Automation: Requires manual startup and connection to appliances using extension cords.


The choice between a home generator and a portable generator depends on specific needs, such as the scale of power requirements, mobility, and the duration of backup power needed. Home generators are ideal for prolonged outages and whole-home backup, while portable generators offer flexibility and convenience for temporary or smaller-scale power needs.


How Long Do Solar Batteries Last?

Lithium-ion batteries are commonly used in solar energy storage systems due to their higher energy density and longer lifespan. High-quality lithium-ion batteries can last anywhere from 10 to 20 years or more. The exact lifespan depends on factors like the specific lithium-ion chemistry, energy storage usage patterns, and environmental conditions.


Among lithium-ion solar battery chemistries, lithium iron phosphate (LiFePO4) is known for longevity, which is an important consideration in the solar battery vs generator debate. LiFePO4 batteries have a higher cycle life, often exceeding 10,000 charge-discharge cycles, making them suitable for long-term use in solar energy storage systems. Their stable chemistry and thermal performance contribute to extended battery lifespan, providing reliable and efficient energy storage for solar applications.


It's important to note that the term "lifespan" in the context of solar battery backup often refers to the period during which the battery can retain a certain percentage of its original capacity. For example, a battery may be considered at the end of its lifespan when it retains only 80% of its initial capacity. However, even a solar battery with 80% of its original capacity may still provide a lot of value.


What is a Solar Backup Generator?

A solar backup generator or solar battery backup is a system that combines solar panels with an energy storage solution, typically batteries, to provide a reliable source of power during grid outages. It captures and stores solar energy when the grid is active, allowing homeowners or businesses to use stored energy when needed, ensuring uninterrupted power supply and enhancing resilience to power disruptions.


Do You Need Solar Panels To Have A Battery?

Solar energy is not required to install a battery at your home. The key difference is that you cannot “refuel” a battery without sunlight during a grid failure like you can refuel a gas generator (assuming you have access to fuel). A battery can be charged from grid power, but you are always at the mercy of your utility pricing by going this route.


With solar battery backup, you can charge and recharge, maintenance-free. There is a common misconception that solar only works in sunny “hotspots” in the United States. However, there are enough quality sun hours a day to provide a large portion of households in the United States with enough energy to fully charge a battery.


solar battery backup vs generator

Best Solar Battery Backup Options

When comparing solar vs generator solutions, it’s crucial to help homeowners choose the right battery backup system based on their unique circumstances. Here are some factors to consider when recommending solar battery backups:

  • Configuration: Batteries can be either AC- or DC-coupled, and the best choice depends on the existing solar installation and inverter compatibility.

  • Capacity: Larger batteries store more solar power, helping homeowners reduce energy bills further, especially when grid electricity rates are high.

  • Cost: Price is a significant consideration in the solar vs generator debate. Solar batteries often have higher upfront costs, but offer long-term savings by using renewable energy, whereas generators have ongoing fuel expenses.

  • Solar-readiness: Some batteries integrate easily with solar PV systems, while others may require costly modifications. Choosing solar-ready batteries simplifies installation and lowers costs.

  • Design: Modern solar batteries come in sleek designs, making them aesthetically pleasing and easier to integrate into homes.

  • Warranty: Consider warranties for depth of discharge (DoD) and production capacity, as they indicate a battery’s lifespan and performance confidence.


Popular options like the Tesla Powerwall 3, LG Chem RESU, Sonnen Eco, Panasonic EverVolt, and Enphase IQ offer reliability and performance, making them ideal for homeowners who prioritize energy independence and clean power. Choosing between solar vs generator depends on clients' needs, but solar batteries often provide a more sustainable and long-term energy solution.


Tesla Powerwall 3 Solar Battery

Best for: Homeowners seeking a high-efficiency battery with superior depth of discharge (DoD) and advanced features.


Average cost: The Tesla Powerwall 3 is priced around $10,000 to $13,000 per unit. Multiple units may be required to meet higher energy storage needs.


Tesla's Powerwall 3 builds on its predecessor's success, offering even greater energy storage capacity and better integration with solar systems. It features a high DoD, allowing homeowners to maximize energy use, and comes with a 10-year warranty. This AC-coupled, lithium-ion battery supports efficient energy storage and offers compatibility with various solar configurations, making it a versatile option for residential use.


In the solar vs. battery debate, the Powerwall 3 offers lower long-term maintenance, renewable energy sourcing, and quieter operation compared to a traditional generator. However, unlike generators that rely on fuel, they recharge via solar, making them more environmentally friendly. It’s also designed to be stackable, allowing for greater scalability in energy storage for larger homes or businesses.


Enphase IQ Solar Battery

Best for: Customizable configurations across various models (IQ 3, IQ 3T, IQ 10, and IQ 10T).


Average cost: Prices range from approximately $3,000 to $9,000, depending on the model and capacity.


The Enphase IQ solar battery lineup features four distinct models, each designed to cater to different energy storage needs and available space. These AC-coupled batteries leverage Enphase's advanced microinverter technology, which is known for enhancing safety and reliability compared to traditional battery systems. This feature positions the Enphase IQ well in the solar battery vs. generator comparison, as it enables homeowners to store solar energy efficiently for later use.


However, one limitation of the Enphase IQ system is its compatibility—it only functions with systems that utilize Enphase inverters. This can restrict flexibility in pairing with various solar configurations. On the plus side, the Enphase IQ batteries come with a 10-year warranty, with the option to extend it for an additional five years, offering peace of mind for homeowners.


generator vs solar panels

Best Home Generators

While solar batteries are becoming increasingly popular, there are circumstances where a home generator might be the better choice. For instance, homeowners who own infrequently used properties, like remote cabins, often find it hard to justify the expense of installing solar panels and energy storage systems. In such cases, generators can provide on-demand power for those occasional needs. Also, many backup generators are portable, allowing users to move them as necessary.


Even if you don't specialize in generator installation, familiarizing yourself with some of the top brands can help you discuss your clients' options effectively, especially in the generators vs solar panels debate. Knowing the advantages and drawbacks can aid homeowners in making informed decisions tailored to their specific energy requirements.


Generac 20kW 6244 Home Generator

Best for: Those who need emergency backup solutions capable of powering their entire homes during power outages


Average cost: The Generac 20kW 6244 currently retails for $5,000 to $7,000.


This whole-house generator has an air-cooled aluminum enclosure and technology that allows it to safely and efficiently power any household item. A 200A auto transfer switch allows it to power an entire home, as opposed to only critical loads as a battery would.


Westinghouse WGen7500 Generator

Best for: Homeowners who want reliable backup power with minimal setup and maintenance.


Average cost: The Westinghouse WGen7500 retails for just under $1,000 on Amazon and other retailers.


This electric start generator scores points on its portability and ease of use. With minimal assembly, it delivers 7,500 W of reliable power at the push of a button. The WGen7500 comes with 6.6 gallons of fuel capacity and can run continuously for up to 11 hours on a full tank.


Choosing Between a Generator Vs. Solar Panels

Solar battery backup has skyrocketed in popularity in recent years. Understanding the differences, benefits, and drawbacks of solar batteries vs generators can provide your clients with the necessary information to make the best decision.


solar battery vs generator

GreenLancer offers design and engineering for solar battery backup and generators. Installers can sign up for free and shop an online catalog with fast turnaround, on-demand, standardized services.





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