Switching to solar energy is an eco-friendly and financially sound decision. However, determining the accurate installation capacity for your home PV system can be challenging. This guide will walk you through the steps needed to calculate the ideal capacity for your PV system, ensuring that you optimise investment.

Step 1: Determine Your Energy Consumption

Before you embark on your solar journey, it’s crucial to understand your average energy consumption. You can find this information on your utility bill or by conducting an energy audit. The goal is to estimate the amount of energy you want your PV system to produce, aiming to cover a significant portion, if not all, of your household electricity needs. Don’t forget to evaluate any potential future electricity demands, such as additional air conditioning or the need to charge electric vehicles.


Average Monthly Energy Usage:  450 kWh Units

Provision for Future Electricity Demand increase:  +100 kWh Units

Total Required Energy per month:  550 kWh Units


Step 2: Calculate the required system capacity

Sunlight availability varies by location and time of year. Research the number of sun hours your area receives to estimate how much solar energy your PV system can harness. You can find this data online or by consulting Hayleys Solar.


Sun Hours in Your Area (per day): 3.8 hours

Estimated Daily Energy Generation per kWp: 3.8kWh Units

Required System Capacity:  550 kWh / 30 days /3.8kWh  = 4.82 kW Units

Recommended System Capacity:  5 kW Units


Step 3: Calculate the Number of Panels

With the required system capacity determined, divide it by the capacity of each panel. For instance, if your calculated system capacity is 5kW and each panel has a capacity of 500W, you would need 10 panels. Make sure to consider the specifics of the panels you choose, which can affect the overall system configuration.


Panel Capacity: 500W each

Number of Panels Needed:  5000W (5 kW) / 500W = 10 panels

Recommended Number of Panels:  10 panels


Step 4: Assessing Your Roof Space

Measuring the available roof space is a crucial step in determining the potential capacity of your PV system. Begin by measuring the unshaded area on your roof where solar panels can be installed effectively. Unlike other regions, Sri Lanka, located close to the equator, enjoys efficient solar energy generation regardless of the panel direction. While the ideal panel orientation is typically south-facing, it’s important to consider the roof’s inclination, which can impact energy generation. In our country, the general rule of thumb for roof inclination is approximately 10 degrees, which ensures that most sunlight is captured.


Size of a Single Panel Approx: 28 sq.ft

Installable Panel Quantity: 10 Panels

Required Roof Space: 28 * 10 = 280 sq.ft


Selecting the right installation capacity for your home PV system is a crucial step toward maximising your solar energy benefits. By following the steps outlined above, you can accurately estimate the ideal capacity for your PV system, generating the energy required to power your daily activities. For high-quality solar panels and professional expertise, consider reaching out to Hayleys Solar, the renewable energy arm of Hayleys Fentons.

Batteries play a crucial role in solar power systems, allowing users to store excess electricity generated by solar panels for later use during power outages, peak demand periods, or at night. Your solar energy setup will be more efficient and cost-effective if you choose the right battery.

Let’s guide you through choosing the perfect battery for your energy storage needs.

Step 1: Determine Your Energy Storage Needs

First, assess your energy storage needs to select the appropriate solar power system battery; analyze your electricity consumption patterns, and identify your backup power needs. The selected battery should have an appropriate capacity that matches or exceeds these energy storage needs. Additionally, consider the battery’s Depth of Discharge (DoD) capability, as some batteries cannot be fully discharged up to 100%.

Step 2: Choose the Right Battery Type Based on Budget, Lifespan, and Safety

There are several battery types available for solar power systems, each with its own advantages and limitations. Consider your budget, expected lifespan, and safety requirements when making your choice:

  1. Lead-Acid Batteries:

– Common and affordable but have a shorter lifespan (approximately 300 cycles) and require regular maintenance. Available varieties include VRLA, Tubular, Flooded, and Sealed.

– VRLA batteries have an average lifespan depending on battery quality, operating conditions, and DoD levels, hence proper management is key.

– Tubular batteries are suitable for deep-cycle applications, offering higher DoD (around 50-80% and higher) compared to regular lead-acid batteries.

  1. Lithium-ion Batteries:

– More expensive but offer a longer lifespan and require less maintenance.

– Lithium-ion Phosphate (LiFePO4) batteries have 6000-10,000 charging cycles, lasting over 16 years if discharged once daily.

  1. Flow Batteries:

– An emerging technology with limited commercially available brands.

Step 3: Check Battery Features, Depth of Discharge, and Cycle Life

Evaluate the features of each battery type, paying attention to the Depth of Discharge (DoD) and cycle life. The DoD determines the usable capacity before recharging, while the cycle life indicates the number of charge/discharge cycles the battery can endure.

Step 4: Consider Environmental Conditions for Battery Storage

Ensure your battery is stored in optimal environmental conditions to maximize its lifespan and performance. Keep the battery in temperatures between 20°C to 25°C to prevent accelerated degradation. Extreme temperatures, high humidity, and direct sunlight exposure can harm battery health, so proper ventilation and moisture protection are essential.

Selecting the best-suited battery for your solar power system is crucial for optimal energy storage and cost-effectiveness. By carefully analyzing your energy storage needs, comparing battery types, and considering environmental factors, you can make an informed decision that ensures a reliable and sustainable solar energy solution for years to come.

Hayleys Solar, the renewable energy arm of Fentons Ltd predominantly focuses on Solar PV installations for the domestic, commercial, and industrial market segments as well as utility-scale projects to enable greater utilisation of sustainable energy resources in the country.  Hayleys Solar has successfully completed over 140MW of solar installations island wide making it the undisputed leader in Engineering, Procurement, and Construction (EPC) company in Sri Lanka.

The inverter is a critical component of the solar panel system – its ‘brain’. The inverter converts the DC electricity produced by the solar panels into AC electricity that can be used in your home or business or sold to the utility. It also must include key safety features required by the Ceylon Electricity Board (CEB) and the Lanka Electricity Company (Private) Limited (LECO).

Here are the steps to select the best-suited inverter for your solar panel system:

A) Ensure the capacity is suitable for the needs of your home or business.

Your energy needs will depend on factors such as your home or business size, the number of occupants, and the appliances you use. The inverter should have a capacity that matches your energy needs. Oversizing the inverter is not recommended as underloaded inverters generate more harmonics, resulting in poor-quality electricity output.

B) Choose between string inverters and micro-inverters based on your system size and shading issues.

String inverters are the most common type and are suitable for systems with minimal shading issues. Shading issues refer to the obstruction or partial covering of solar panels by nearby objects, such as trees, buildings, or other structures, which can result in reduced energy production. Micro-inverters are ideal for systems with partial shading problems or when you have a multipaned roof, as they guide each panel to generate independently (this is called MPPT tracking).

C) Check the certifications and features of the inverter, such as efficiency, voltage range, and monitoring capabilities.

  • The inverter should have certifications from recognized bodies such as UL, TUV, or IEC.
  • The inverter’s efficiency will determine how much electricity is lost during conversion.
  • The voltage range should match the DC voltage of your solar panels
  • The inverter should have monitoring capabilities to track the system’s performance. Also, if the inverter is placed outside, the IP rating of the inverter has to be considered.

D) Select a reputable brand that offers warranties and after-sales service.

Choose a brand that has a proven track record of reliability and offers warranties and after-sales service to ensure the longevity and performance of your solar panel system.

Hayleys Solar Inverters offer high-quality, efficient, and reliable solutions for all solar power systems. Designed to cater to a wide range of commercial, industrial, and residential applications, these inverters can handle capacities ranging from 1kW to 100kW. Hayleys Solar inverter brands use multiple MPPT tracking technology, allowing maximum energy harvest from your solar panels. These inverters are backed by a 10-year warranty, giving you peace of mind and protecting your investment.

Notably, the most common cause of inverter failure is grid surges and lightning strikes, which are not covered under the manufacturer’s warranty. We strongly recommend that you insure your inverter and the entire solar panel system as a precaution to enjoy added protection and peace of mind.

With the growing need for clean and renewable energy sources, solar power has become an increasingly popular option for Sri Lankan homeowners. However, selecting the best-suited solar panel system for your needs can be a daunting task. It requires careful consideration of several factors, such as energy needs, system size, shading issues, and safety requirements. Making the right decision can maximize energy production and cost savings, while a poor choice can lead to inefficiencies and long-term expenses. As the No.1 solar provider in Sri Lanka, Hayleys Solar has the expertise and experience to help homeowners make informed decisions.

  • Panel technology:

Panel technology plays a crucial role in the performance and reliability of solar panels. Hayleys Solar offers high-quality  solar panel technology, including the Mono PERC panels. These panels are 500Wp and above, making them suitable for various solar energy needs. The  technology used in these panels is Monocrystalline PERC, known for its high efficiency and reliability.

  • Size:

Size is another important consideration when selecting solar panels. The Mono PERC panels from Hayleys Solar come in two sizes, providing installation flexibility. The smallest size is 1960 x 991 x 40 mm, while the largest size is 2279 x 1134 x 35 mm. Homeowners can choose the size that best fits their available space and energy requirements.

  • Warranty: 

Warranty is a crucial factor to consider when investing in solar panels. Hayleys Solar offers a 12-year warranty for their Mono PERC panels. This warranty covers any defects or issues with the panels and ensures that they perform optimally without material failures. In addition, Hayleys Solar provides a performance guarantee of up to 25 years, ensuring that the panels maintain a minimum of 84.8% efficiency even after 25 years of use. This long-term warranty and performance guarantee provide homeowners with peace of mind and confidence in their investment.

  • Efficiency and temperature coefficient:

Efficiency and temperature coefficient are key indicators of solar panel performance. The efficiency of the Mono PERC panels from Hayleys Solar can go up to 21.7%, which is relatively high for solar panels. This high efficiency translates to greater energy production and higher cost savings. Additionally, the temperature coefficient of these panels is -0.35%/°C, meaning that they can perform well in a wide range of temperatures. This feature makes the Mono PERC panels from Hayleys Solar among the most efficient and reliable solar panels available in the market.

When it comes to selecting the best-suited solar panel system for your home, Hayleys Solar offers a comprehensive range of options. Their Mono PERC panels with advanced technology, different sizes, and impressive warranty and performance guarantees ensure that homeowners can make an informed decision.

Take the first step towards a sustainable future by using our Solar Bill Calculator. Enter your monthly electricity bill amount, and we’ll provide you with an estimate of how much solar energy kWh can be generated and the potential reduction in units per month. Discover how Hayleys Solar can help you bring your electricity bill to zero with our innovative solar power solutions.

Visit our website and use the Solar Bill Calculator today! https://www.hayleyssolar.com/#bill_cal

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