Harnessing the power of the sun, solar power offers a world of freedom and efficiency for RV and travel trailer owners. This guide delves into the realm of solar panels for recreational vehicles (RVs), exploring their benefits, types, and operational principles. As a renewable energy source, solar power stands as a game-changer in the RV world, providing a sustainable and cost-effective means of energy, perfect for life on the road.
What Are RV Solar Panels?
RV solar panels are specialized devices designed to convert sunlight into electrical energy for use in recreational vehicles. Unlike their residential counterparts, these panels are crafted for mobility and efficiency in varying environments.
What are the Types of RV Solar Panels
Monocrystalline
Monocrystalline solar panels, recognizable by their dark black color, are made from single-crystal silicon, allowing for more efficient energy conversion.
High Efficiency: Their efficiency rates, typically between 15-20%, allow them to convert more sunlight into electricity than other types.
Sleek Design: They have a uniform appearance and are aesthetically pleasing, making them an attractive option for RVs.
Space Efficiency: Best for RVs with limited roof space as they provide the highest power output per square foot.
Durability: These panels are known for their longevity and excellent performance in low-light conditions.
Cost: While they are more expensive per watt, their longevity and efficiency can offer better value over time.
Heat Tolerance: They perform slightly better than other types in high-temperature environments.
Polycrystalline
Polycrystalline solar panels are made from multiple silicon fragments melted together, giving them a distinctive blue, speckled appearance.
Cost-Effective: They are more affordable than monocrystalline panels, making them a popular choice for budget-conscious RV owners.
Efficiency: Typically, they have efficiency rates of about 13-16%, requiring more space to generate the same power as monocrystalline panels.
Temperature Tolerance: These panels perform well in high-temperature environments, though slightly less efficiently than monocrystalline panels.
Environmental Impact: The manufacturing process of polycrystalline panels results in less silicon waste, making them a more environmentally friendly option.
Durability: While durable, they may have a shorter lifespan than monocrystalline panels.
Thin-Film
Thin-film solar panels are made by layering one or more thin photovoltaic materials on a substrate. They are known for their flexibility and lightweight design.
Flexibility: Their ability to bend makes them suitable for curved surfaces and unique RV designs.
Ease of Installation: These panels can be easier to install due to their flexibility and lighter weight, allowing for more versatile placement options.
Efficiency: Generally, thin-film panels have lower efficiency rates (around 10-13%), so they require more space for the same power output as crystalline panels.
Cost: Thin-film panels are typically less expensive, making them a budget-friendly option for larger installations.
Durability: They can degrade faster than crystalline panels, which may affect their lifespan and efficiency.
Shade Tolerance: Better performance in low-light and partial shading conditions compared to crystalline panels.
Weight: Their lightweight nature can be advantageous for RVs with weight limitations.
How Do RV Solar Panels Work?
RV solar panels work by absorbing sunlight and converting it into electricity. This electricity is then used to power various appliances and devices within the RV. The solar power system typically comprises panels, a charge controller, a battery bank, and an inverter, creating a complete solution for off-grid living.
What are the Essential Components of an RV Solar System?
Embarking on the adventure of RV living with solar power requires a deep understanding of the essential components that make up a solar system. Each element plays a crucial role in harnessing, storing, and converting solar energy into usable power for your RV. Let’s explore these components and their functions to gain a comprehensive view of an RV solar system.
Solar Panels
Function: Solar panels are the heart of the solar system, converting sunlight into electrical energy.
Types: Common types include monocrystalline, polycrystalline, and thin-film, each with varying efficiencies and sizes suitable for different RV roofs.
Battery Bank
Function: The battery bank stores the energy generated by the solar panels for later use.
Types: Options include lead-acid, lithium-ion, and AGM (Absorbent Glass Mat) batteries, each offering different benefits in terms of lifespan, capacity, and maintenance needs.
Inverter
Function: Inverters convert the direct current (DC) power stored in the batteries into alternating current (AC) power, which is used to run standard electrical appliances.
Types: There are two main types of inverters: modified sine wave and pure sine wave. Pure sine wave inverters are generally preferred for their ability to run sensitive electronic devices more efficiently.
Charge Controller
Function: A charge controller regulates the voltage and current coming from the solar panels to the battery bank, protecting the batteries from overcharging and prolonging their life.
Types: The two primary types are PWM (Pulse Width Modulation) and MPPT (Maximum Power Point Tracking), with MPPT being more efficient in converting solar energy, especially in varying weather conditions.
Additional Components
Solar Charge Regulator
Function: A solar charge regulator is another form of a charge controller, specifically designed to protect the battery from overcharging and over-discharging.
DC-DC Converter
Function: This component is used to step down or step up DC voltages from the solar panels to match the RV’s electrical system requirements.
Solar Meter
Function: A solar meter provides real-time data on the performance of your solar system, including voltage, current, and power generation.
Mounting Hardware
Function: Mounting hardware is essential for securely attaching solar panels to your RV’s roof. It includes brackets, clamps, and rails designed to withstand the rigors of travel.
Wiring and Connectors
Function: Proper wiring and connectors are crucial for safely and efficiently transferring electricity from the solar panels to the battery bank and inverter.
Circuit Breakers and Fuses
Function: These components provide essential safety features for your solar system, protecting against electrical overload and short circuits.
Energy Management System
Function: An energy management system helps optimize the use of solar power by efficiently distributing energy among various appliances and storage systems.
Remote Monitoring
Function: Remote monitoring systems allow you to keep track of your solar system’s performance from a distance, often through a smartphone app.
Grounding Components
Function: Grounding components ensure the safety of your solar system by protecting against electrical surges and lightning strikes.
Surge Protectors
Function: Surge protectors safeguard your solar system and connected appliances from voltage spikes and power surges.
Understanding Battery Options for Solar RV Systems: Gel, Lithium-ion, and Absorbed Glass Mat Batteries
Gel Batteries
Gel batteries, known for their robustness and reliability, use a thick, gelified electrolyte instead of liquid. This unique composition makes them particularly suited for challenging conditions.
The gelified electrolyte minimizes spillage and off-gassing, and these batteries are less prone to damage from vibration and shock, making them ideal for mobile applications like RVs.
Advantages
Deep Discharge Recovery: Exceptional at handling deep discharge cycles, making them suitable for extended off-grid use.
Temperature Resilience: Perform reliably across a wide temperature range, from very cold to very hot conditions.
Maintenance-Free: Require no watering or regular maintenance, offering convenience and ease of use.
Usage
Best for RV solar systems where consistent and dependable power is crucial, especially in environments where rough terrain or extreme temperatures are common.
Lithium-ion Batteries
Lithium-ion batteries represent the cutting edge in battery technology, offering high efficiency and energy density. They are increasingly popular in modern RV solar systems.
Known for their long lifespan and consistent performance, these batteries can handle numerous charge and discharge cycles with minimal degradation.
Advantages
Long Lifespan: Can last several years longer than traditional lead-acid batteries, making them a cost-effective option in the long term.
Rapid Charging: Capable of faster charging, which is beneficial when solar input is variable.
Lightweight: Significantly lighter than lead-acid batteries, reducing the overall weight of the RV.
Usage
Ideal for those who prioritize efficiency and longevity in their RV solar system, and for those who frequently travel or live full-time in their RV.
Absorbed Glass Mat (AGM) Batteries
AGM batteries are a type of lead-acid battery that use a fiberglass mat to absorb the electrolyte, making them more stable and robust than traditional lead-acid batteries.
The fiberglass matting between the battery plates enhances the battery’s stability and performance, making them a reliable power source.
Advantages
Spill-Proof and Safe: The absorbed electrolyte reduces the risk of spills and makes them safer to use in various orientations.
Low Self-Discharge Rate: Retain their charge for longer when not in use, making them suitable for seasonal or occasional RV users.
Improved Durability: More resistant to vibration and shock than traditional batteries, enhancing their longevity.
Usage
These batteries are particularly well-suited for solar RV systems that demand a robust, maintenance-free battery capable of withstanding diverse environmental conditions.
Choosing the Right Solar Charge Controller and Inverter
Solar Charge Controller
Function: A solar charge controller manages the flow of power from the solar panels to the battery bank, ensuring batteries are charged safely and efficiently.
Types: The two main types are PWM (Pulse Width Modulation) and MPPT (Maximum Power Point Tracking). PWM is more cost-effective but less efficient, while MPPT offers greater efficiency, especially in varying weather conditions.
Selection Tips: Choose an MPPT controller for larger systems or systems in areas with fluctuating weather. For smaller setups or fixed installations, a PWM controller may suffice.
Power Inverter
Function: The inverter converts DC electricity from the solar panels and batteries into AC electricity, which powers most household appliances.
Types: Pure sine wave inverters are preferred for their ability to run sensitive electronic devices without interference. Modified sine wave inverters are more affordable but may not be compatible with all devices.
Selection Tips: For running sensitive electronics like laptops or medical equipment, opt for a pure sine wave inverter. If your power needs are basic, a modified sine wave inverter could be a cost-effective choice.
Is Solar Power Right for Your RV?
The decision to incorporate solar power into your RV lifestyle is a pivotal one. It’s a journey that begins with understanding the nuances of solar energy, how it aligns with your travel needs, and the unique challenges and rewards it presents. As the sun’s rays offer a promise of freedom and self-sufficiency, it’s crucial to weigh the advantages and disadvantages carefully.
Exploring the Suitability of Solar Panels for Your RV
When considering solar power for your RV, it’s essential to evaluate your travel habits, power needs, and geographical preferences. Solar power, with its ability to harness the sun’s energy, offers an appealing off-grid option. However, its efficacy largely depends on factors like the amount of sunlight your destinations receive, the energy consumption of your RV appliances, and the feasibility of installing the necessary components.
Factors to Consider:
Sunlight Exposure: The effectiveness of solar panels hinges on the amount of sunlight they receive. RVs frequently journeying through sun-rich areas will benefit more.
Energy Requirements: Your RV’s power needs, dictated by the appliances and devices you use, play a crucial role in determining the size and capacity of your solar system.
Space for Panels: The availability of adequate roof space on your RV is essential for solar panel installation. Larger systems may require more space than available on smaller RVs.
Advantages and Disadvantages of Using Solar Power in RVs
Advantages
Sustainable Energy Source: Solar power, being renewable, aligns with eco-friendly living.
Cost-Effective in the Long Run: Despite the initial investment, solar panels can offer significant savings on energy costs over time.
Independence from the Grid: Solar panels provide the freedom to explore remote locations without relying on conventional power sources.
Disadvantages
Initial Investment: The upfront cost of purchasing and installing solar panels can be substantial.
Weather Dependence: Solar power efficiency is contingent on sunlight availability, making it less reliable in cloudy or rainy conditions.
Maintenance Requirements: While generally low, solar panels and associated equipment require regular maintenance to ensure optimal performance.
How Many Solar Panels Do You Need to Run Common RV Appliances?
Determining the number of solar panels needed for your RV is a crucial step in optimizing your solar system. This decision hinges on understanding your power needs and the energy consumption of common RV appliances. Let’s explore how to calculate watt usage and navigate the solar requirements for an RV lifestyle.
Calculating Your RV’s Power Requirements: Understanding Wattage and Consumption
To adequately size your RV solar system, you must first understand the energy demands of your RV appliances. Calculating the total wattage required involves identifying the power consumption of each device and appliance you plan to use. This calculation gives you a clear picture of your daily power needs, essential for selecting the appropriate number and type of solar panels.
Key Factors to Consider are:
Appliance Wattage: Identify the wattage of each appliance. This information is usually found on the appliance or in its manual.
Usage Duration: Determine how long each appliance runs daily. The total energy consumption is the product of wattage and usage time.
Energy Efficiency: Consider the energy efficiency of your appliances. More efficient devices consume less power, impacting the total solar power required.
Estimating Consumption for Common Appliances
Let’s see some common RV appliances and their wattage:
Refrigerator: A typical RV refrigerator consumes about 150-200 watts when running. However, it doesn’t run continuously, so average daily consumption might be lower.
Air Conditioner: One of the most power-hungry appliances, a standard RV air conditioner can use around 1,500 watts.
Lights: LED lights in RVs are energy-efficient, with each bulb consuming about 1-10 watts.
Microwave: A microwave can use about 1,000 watts during operation, but its usage is usually short-lived.
TV: An average flat-screen TV uses about 100-150 watts.
Coffee Maker: A typical coffee maker uses around 600-800 watts.
Laptop/Phone Chargers: These devices are relatively low in power consumption, typically around 20-50 watts.
Balancing Solar Panel Capacity with Energy Consumption
Once you have a comprehensive understanding of your energy requirements, the next step is to match it with the solar panel’s capacity. Solar panels are rated by the amount of electricity they can produce in ideal sunlight conditions, measured in watts. For instance, a 100-watt panel can produce 100 watts of electricity per hour under ideal conditions. However, it’s crucial to factor in real-world conditions like partial shading, angle of the sun, and temperature, which can affect the panel’s output:
Sunlight Exposure: The amount of direct sunlight your panels receive dramatically impacts their efficiency. Ideal conditions are not always met, especially when traveling.
Panel Angle and Placement: The angle at which solar panels are mounted affects their ability to capture sunlight efficiently.
Temperature: Extreme temperatures can affect solar panel performance. Cooler conditions generally allow for better efficiency.
Calculating Total Solar Panel Requirements
To determine the total number of solar panels needed, divide your total daily watt-hour requirement by the wattage of a single solar panel, considering inefficiencies and non-ideal conditions. For example, if your daily energy need is 2,000 watt-hours and you’re using 100-watt panels, you’ll need at least 20 panels under ideal conditions. Accounting for inefficiencies, you might consider adding more panels to ensure adequate power supply.
How much does a Solar RV System Cost?
Investing in a solar RV system requires careful financial planning and understanding of the costs involved. This section provides a breakdown of the various expenses you’ll encounter, offering average price ranges in USD for different types of solar RV systems and panels.
Solar Panel Cost
Monocrystalline Panels: Ranging from $1.50 to $2.50 per watt, these panels are efficient and space-saving. A typical 100-watt panel may cost between $150 and $250.
Polycrystalline Panels: Slightly less efficient, these panels cost around $1.00 to $1.50 per watt. A standard 100-watt panel would be priced between $100 and $150.
Thin-Film Panels: The most affordable, ranging from $0.70 to $1.00 per watt. However, they require more space and are less efficient.
Installation Costs
DIY Installation: Primarily involves the cost of tools and additional materials, which can range from $100 to $200.
Professional Installation: Costs vary widely but can range from $1,000 to $3,000, depending on system complexity and labor rates.
Maintenance Costs
Routine Maintenance: Generally low, involving cleaning and occasional checks, averaging around $50 to $100 per year.
Battery Replacement: Depending on the battery type, costs can range from $200 for lead-acid to over $1,000 for advanced lithium batteries, usually every 5 to 7 years.
What is the Lifespan of RV Solar Panels?
The lifespan of RV solar panels is a key consideration in your investment. Understanding how long they will effectively provide power is crucial for long-term planning.
Monocrystalline and Polycrystalline Panels: Typically last between 25 and 30 years.
Thin-Film Panels: Have a shorter lifespan, generally around 15 to 20 years.
Factors Influencing Lifespan
Quality of Panels
Manufacturing Quality: Higher quality panels tend to last longer.
Warranty Period: Often reflects the manufacturer’s confidence in their product’s longevity.
Environmental Factors
Exposure to Extreme Weather: Harsh weather conditions can shorten a panel’s lifespan.
Temperature Fluctuations: Constant changes in temperature can stress the materials, leading to quicker degradation.
Maintenance and Care
Regular Cleaning: Removing debris and dust can improve longevity.
Inspection and Repairs: Promptly addressing any damages or loose connections.
Installation Quality
Proper Installation: Ensuring panels are correctly mounted can prevent physical damage.
Wiring and Connectivity: Proper electrical connections are essential for maintaining panel efficiency.
Installing Your RV Solar Panel System
Embarking on the installation of a solar panel system for your RV is a significant step towards energy independence and sustainable travel. This guide provides a detailed, step-by-step approach to installing an RV solar system, ensuring a safe and efficient setup.
Step-by-Step Guide to Installing an RV Solar System
Planning and Preparation
Evaluate Power Needs: Determine the wattage requirements of your RV to decide the size and number of solar panels needed.
Select Components: Choose solar panels, a charge controller, batteries, and an inverter suitable for your RV’s power needs and space limitations.
Mounting Solar Panels
Choose Location: Select a spot on the RV roof with maximum sun exposure and minimal shading.
Install Mounting Brackets: Securely attach the mounting brackets to the roof, ensuring they are properly sealed to prevent leaks.
Mount Panels: Attach the solar panels to the brackets, making sure they are stable and well-aligned.
Wiring the Panels
Connect Panels: Wire the solar panels in series or parallel, depending on the desired voltage and amperage.
Run Wiring: Carefully route the wiring from the panels to the charge controller location, using UV-resistant wiring and connectors.
Installing the Charge Controller
Mount Charge Controller: Install the charge controller in a convenient location, away from direct sunlight and moisture.
Connect Panels to Charge Controller: Wire the solar panels to the charge controller, following the manufacturer’s instructions.
Setting Up the Battery Bank
Choose Location: Place the batteries in a ventilated, accessible area, away from living spaces.
Connect Batteries: Wire the batteries in series or parallel, based on your system’s voltage requirements.
Link to Charge Controller: Connect the battery bank to the charge controller, ensuring correct polarity.
Inverter Installation
Install Inverter: Mount the inverter close to the batteries but in a space that is dry and well-ventilated.
Connect to Batteries: Wire the inverter to the battery bank, adhering to the inverter’s specifications.
Finalizing the Setup
Ground the System: Properly ground the solar system to protect against electrical surges.
Test the System: Power on the system and check all connections for proper functioning.
Safety Considerations During Installation
Safety is paramount when installing an RV solar system. Here are key considerations to ensure a safe installation process:
Turn Off Power Sources: Before starting, ensure all power sources are turned off to avoid electric shocks.
Use Proper Tools: Utilize the correct tools and equipment, and wear protective gear.
Secure Rooftop Access: Use a stable ladder and safety harness when working on the roof.
Follow Manufacturer Guidelines: Adhere strictly to the installation guidelines provided by the component manufacturers.
Check for Leaks: After installing rooftop components, check for any potential leaks.
DIY vs. Professional Installation: What to Consider
Deciding between DIY and professional installation involves several factors:
DIY Installation
Pros: Cost savings, a deeper understanding of your system, and a sense of accomplishment.
Cons: Time-consuming, risk of incorrect installation, potential voiding of warranties.
Professional Installation
Pros: Expertise and experience, faster installation, often comes with warranties and support.
Cons: Higher cost, less personal involvement in the process.
Maintenance and Care for Your RV Solar Panels
Proper maintenance and care are essential for maximizing the lifespan and efficiency of your RV solar panels. Regular upkeep not only enhances performance but also ensures your system remains reliable throughout your travels. Here are practical and actionable recommendations to keep your solar system in top condition.
Tips and Guidelines for Maintaining Your Solar System
Regular Cleaning
Frequency: Clean the solar panels every few months or more frequently if you’re traveling through dusty or snowy areas.
Method: Use a soft brush or cloth and mild detergent. Avoid abrasive materials that can scratch the panels.
Inspections
Routine Checks: Inspect the panels and mounting hardware for any signs of damage, corrosion, or loose connections.
Electrical Connections: Ensure all wiring is intact and secure. Look for any signs of wear or damage.
Battery Maintenance
Battery Health: Regularly check your battery bank’s state, especially if you’re using lead-acid batteries. Ensure they are charged and not over-discharged.
Connections and Ventilation: Ensure battery connections are tight and free from corrosion. Batteries should be well-ventilated to prevent overheating.
Charge Controller and Inverter Care
Functionality Check: Periodically check the charge controller and inverter for proper functioning. Look for any error messages or alerts.
Firmware Updates: Keep the software for smart controllers and inverters up-to-date for optimal performance.
Preventive Measures
Shading Analysis: Regularly check for new shading issues caused by tree growth or new structures around your RV.
Weather Protection: If you’re in an area with harsh weather conditions, consider additional protective measures like hail guards.
Advanced Topics in RV Solar Power
Exploring advanced aspects of RV solar power can significantly enhance the efficiency and functionality of your solar system. This section delves into sophisticated strategies and technologies for optimizing solar energy use in RVs.
Off-Grid Modifications and Power Independence
Achieving Self-Sufficiency with Solar Power
Integrating Larger Battery Banks: Using high-capacity batteries like lithium-ion to store more energy, ensuring power availability even during low sunlight periods.
Utilizing Efficient Appliances: Choosing energy-saving appliances reduces overall power consumption, extending off-grid capabilities.
Incorporating Backup Generators: Adding a generator as a backup can provide peace of mind and additional power when solar energy is insufficient.
Harnessing Renewable Energy Sources
Wind Turbine Integration: Complementing solar panels with small wind turbines can increase power generation, especially in windy areas.
Hybrid Systems: Combining solar power with other renewable energy sources like hydro or wind for a more robust and reliable power supply.
Upgrading and Expanding Your Solar System
Enhancing Solar Capacity and Efficiency
Adding Additional Panels: Expanding the number of solar panels to generate more power, accommodating increased energy needs or compensating for less efficient older panels.
Upgrading to Higher Efficiency Panels: Switching to more advanced solar panels, such as monocrystalline, for better performance in limited spaces.
Optimizing System Configuration
Advanced Charge Controllers: Implementing MPPT charge controllers for improved energy conversion efficiency, especially in variable weather conditions.
Upgraded Inverter Systems: Installing higher capacity or more efficient inverters to handle increased power loads and provide cleaner power output.
Smart Solar: Integrating Technology for Efficiency
Smart Monitoring and Control
Remote Monitoring Systems: Utilizing apps and remote monitoring tools to track energy production, consumption, and system health in real-time.
Automated Energy Management: Implementing smart systems that automatically manage energy distribution based on priority, usage patterns, and storage levels.
Technological Advancements in Solar Energy
Flexible Solar Panels: Exploring the use of flexible panels for unconventional RV roof shapes, improving aesthetic appeal and installation ease.
Solar Power Optimizers: Incorporating power optimizers in the system to maximize energy output from each panel, especially useful in partial shading scenarios.
Conclusion
Transitioning to solar power for RVs and travel trailers represents a significant step towards sustainability and autonomy. Embracing this technology not only reduces your carbon footprint but also enhances the freedom and flexibility inherent in the RV lifestyle.
FAQs
1. What will a 100-watt solar panel run in an RV?
A 100-watt solar panel in an RV can power small devices and basic essentials. It’s suitable for charging smartphones, laptops, LED lights, and small fans. However, it’s not sufficient for energy-intensive appliances like air conditioners or large refrigerators. Ideal for minimal power needs or as a supplementary source.
2. What will a 200-watt solar panel run in an RV?
A 200-watt solar panel can comfortably run several small appliances simultaneously, such as LED lights, a laptop, and a small TV. It can also handle slightly larger devices like a modest-sized refrigerator for short periods, making it suitable for weekend trips or for RVers with moderate energy needs.
3. What can a 1200 watt solar panel power in an RV?
A 1200 watt solar panel system can power several larger appliances in an RV, including a medium-sized refrigerator, microwave, coffee maker, and even a small air conditioner. It’s ideal for those who wish to operate multiple devices simultaneously and sustain a more residential-style living experience in their RV.
4. What will a 500 watt solar panel run in an RV?
A 500-watt solar panel system can handle a variety of appliances, including a small refrigerator, a TV, charging for electronic devices, and several LED lights. It’s well-suited for longer trips and can support a comfortable living experience without overly relying on external power sources.
5. What can a 2000 watt solar panel power in an RV?
A 2000 watt solar panel system can power almost all the essentials of an RV, including air conditioning, a larger refrigerator, a microwave, and multiple electronic devices. This capacity is akin to a residential setup and is suitable for full-time RV living, offering extensive energy independence.
6. Can you run a travel trailer on solar?
Yes, you can run a travel trailer on solar power. The key is to have a well-sized solar panel system and battery bank to meet your power needs. Solar power can handle lighting, charging devices, and running small appliances, making it a viable option for sustainable and off-grid travel.
7. Can solar panels run RV air conditioner?
Solar panels can run an RV air conditioner, but it requires a substantial solar array and battery bank. Typically, a powerful system of around 2000 watts or more is necessary to efficiently operate an air conditioner, along with a suitable inverter and battery setup.
8. Can RVs use residential solar panels?
RVs can use residential solar panels, but considerations include size, weight, and mounting capabilities. Residential panels are typically larger and more powerful, so ensure your RV’s roof can accommodate them. An appropriate charge controller and battery bank are also necessary to manage the increased power output.
9. Can you run an RV air conditioner with solar power?
Running an RV air conditioner with solar power is possible but requires a significant solar setup. A system with high wattage, around 2000 watts or more, alongside a robust battery bank and a powerful inverter, is needed to effectively power an air conditioner for extended periods.
