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How Many Solar Panels Do You Need?

Updated: Mar 8, 2022

When transitioning from standard electricity to solar energy, the size of your solar panel system is defined by one simple question: How much solar do I need? Determining this answer requires reflection on your end goal, whether that be: minimizing environmental contamination, increasing money savings, maximizing Return on Investment (ROI), or jumping onto the neighbour bandwagon.

How Much Power Does Your Home Currently Use?

The first step in determining how many solar panels are necessary on your property is to calculate how many kWhs are currently being used. A kWh is a measure of energy used over time that the utility uses to bill you. A 6-12 month average of your household electricity bill is recommended to create a viable range. The “Kilowatt Hours (kWh) Used” portion of the bill is then broken down into hourly and daily usage.


Case Example

A homeowner’s electricity bill might read that a medium-sized home is currently using 4,800 kWh annually. This number can then be used to calculate a monthly average (4,800 kWh / 12 months), or a daily average of 13.15 kWh (4,800 kWh / 365 days per annual statement). This average can then be divided by 24 hours to determine how much electricity is used each hour of a day. This calculation will tell you how much energy is being consumed so that we can budget what is necessary for your solar panels to produce hourly. You will not be alone in calculating this. Lotalinks Technologies power specialists will be there every step of the way to ensure 100% accuracy and maximization.

How Many Solar Panels Do You Need to Power Your Home?

Just like taking into consideration the many variables when buying your first home, taking into account key factors when budgeting how many solar panels to power a house will pay off in the long run with satisfaction and more money in your pocket. Since solar energy comes from the sun’s radiance, the number of direct sunlight hours and potential shade coverage are important to consider and we look at these factors when designing a system.


Hours of Sunlight Exposure

Knowing how many hours of direct sunlight to expect per day at your home is crucial to how much expected energy your solar panels will produce. If you live in a very sunny location, such as FCT, Abuja, you can expect more energy production per panel then a cloudy state such as Rivers. Evaluating your peak sunlight hours will enable us to determine, based on your daily usage, how many solar panels you would need to maximize your cost savings.


Case Example

Using the case example above as a reference, a home that consumes 4,800 kWh of energy annually will require 13.15 kWh of electricity daily to maintain their current lifestyle. This particular home is in Lagos, and receives around 6 hours of direct sunlight each day. In order to calculate the amount of energy the panels will need to collectively produce daily, divide the average hourly energy consumption (W) by the number of peak sunlight hours in your area per day. Start by converting the average hourly usage from kWh to watts by multiplying 13.15 kWh by 1,000 W. Lastly, divide the converted 13,150 watts needed daily by the 6 hours of peak sunlight. Based on the amount of available sun energy, this home’s panels in Lagos will need 2,192 W.

How Many Solar Panels Do You Need to Maximize Space

Once we've determined the amount of energy we need the panels to output, we’ll begin designing the solar panel system in a way that optimizes the flow of sunlight, visual appeal, and ROI on solar panel-type.


Angle and Size of Roof

Simply put, not all roofs are created equal. If you have an oddly shaped roof, or even a smaller one, consider the size and angle of surface in determining the number of solar panels to acquire the necessary output. Roofs with lots of workable space can warrant sacrificing some efficiency by going with larger, and more cost effective panels to achieve the targeted energy. Some homeowners simply don’t have enough roof space, or some shade coverage, for the solar panels in mind. In this case, investing in smaller, high efficiency panels will provide the most energy output in the space available, while saving the homeowner more money in the long run.

The degree at which the roof slants also will be important in knowing how much sunlight is hitting the panels, and just how much energy can be produced from each panel. We’ll determine the exact combination of panel sizes, based on the angle and size of roof, to get the most bang for your buck and curb appeal.


How Many Solar Panels Do You Need to Maximize Efficiency

Solar panels range in efficiency depending on the type of cell technology. A few of these options include conventional panels and solar panels with no grid lines. The latter of the two absorb more sunlight, which increases efficiency of sunlight conversion. Weighing the factors of roof size and the amount of needed energy makes determining the level of panel efficiency best suited for the solar panel specialists at Lotalinks. We ensure both your budget and panels are maximized, including the visually appealing mounting options that keep the panels efficient and aesthetically pleasing on the backside of your roof.

Example

Calculate Size of Solar Panel

Calculate Size of Solar Panel, No. of Solar Panel and Size of Inverter for following Electrical Load

Electrical Load Detail:

  • 100W Computer use for 8 Hours/Day

  • 2 x 60W Fan use for 8 Hours/Day

  • 100W CFL Light use for 8 Hours/Day

Solar System Detail:

  • Solar System Voltage (As per Battery Bank) = 48V DC

  • Loose Wiring Connection Factor = 20%

  • Daily Sunshine Hour = 6 Hours/Day

Inverter Detail:

  • Future Load Expansion Factor = 10%

  • Inverter Efficiency = 80%

  • Inverter Power Factor =0.8

Calculation:

Step-1: Calculate Electrical Usages per Day

  • Power Consumption for Computer = No. computer x Watt x Use Hours/Day

  • Power Consumption for Computer = 1x100x8 =800 Watt Hr/Day

  • Power Consumption for Fan = No. of fan x Watt x Use Hours/Day

  • Power Consumption for Fan = 2x60x8 = 960 Watt Hr/Day

  • Power Consumption for CFL Light = No. CFL light x Watt x Use Hours/Day

  • Power Consumption for CFL Light = 1x100x8 = 800 Watt Hr/Day

  • Total Electrical Load = 800+960+800 =2560 Watt Hr/Day

Step-2: Calculate Solar Panel Size

  • Average Sunshine Hours = 6 Hours

  • Total Electrical Load =2560 Watt Hr/Day

  • Required Size of Solar Panel = (Electrical Load / Avg. Sunshine) X Correction Factor

  • Required Size of Solar Panel =(2560 / 6) x 1.2 = 512 Watt

  • Required Size of Solar Panel = 512 Watt

Step-3: Calculate No. of Solar Panel / Array of Solar Panel

If we Use 250 Watt, 24V Solar Panel in Series-Parallel Type Connection

  • In Series-Parallel Connection Both Capacity (watt) and Volt are increases

  • No. of String of Solar Panel (Watt) = Size of Solar Panel / Capacity of Each Panel

  • No. of String of Solar Panel ( Watt) = 512 / 250 = 2.05 Say 3 String

  • No. of Solar Panel in Each String= Solar System Volt / Each Solar Panel Volt

  • No. of Solar Panel in Each String= 48/24 =2 Solar Panels

  • Total No. of Solar Panel = No of String of Solar Panel x No of Solar Panel in Each String

  • Total No. of Solar Panel = 3×2 =6

Total No. of Solar Panel =6 Panels


Step-4: Calculate Electrical Load:

  • Load for Computer = No. of computer x Watt

  • Load for Computer = 1×100 =100 Watt

  • Load for Fan = No. of fan x Watt

  • Load for Fan = 2×60 = 120 Watt

  • Load for CFL Light = No. CFL light x Watt

  • Load for CFL Light = 1×100 = 100 Watt

  • Total Electrical Load = 100+120+100 =320 Watt


Step-5: Calculate Size of Inverter:

  • Total Electrical Load in Watt = 320 Watt

  • Total Electrical Load in VA= Watt /P.F

  • Total Electrical Load in VA =320/0.8 = 400VA

  • Size of Inverter =Total Load x Correction Factor / Efficiency

  • Size of Inverter = 320 x 1.2 / 80% =440 Watt

  • Size of Inverter =400 x 1.2 / 80% =600 VA

Size of Inverter = 440 Watt or 600 VA


Summary:

  • Required Size of Solar Panel = 512 Watt

  • Size of Each Solar Panel = 250 Watt. 24 V

  • No of String of Solar Panel = 3

  • No of Solar Panel in Each String = 2

Total No of Solar Panel =6

Total Size of Solar Panel = 1,500 Watt

Size of Inverter = 440 watt or 600 VA


Return on Investment

Making the leap from standard electricity to solar can be a process if not done properly. Rather than comparing panel types, calculating energy usage, and the other factors needed to maximize solar panel ROI on your own, consult with the professionals to achieve whatever energy goals you have set out for.

Here at Lotalinks Technologies, we make this transition a simple one for you by taking into account all of the many things: current home energy consumption, hours of direct sunlight, shade coverage, angle and size of roof, and panel efficiency to ultimately get the best Return on Investment. Get a free quote and complimentary consultation today!


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