Switching to solar is an exciting step toward clean energy, load shedding preparedness, and lower electricity bills. But before getting into it, one of the first things you’ll want to figure out is the right solar panel size: How many panels do you need, and do you have enough space for them?
Whether you’re looking at rooftop setups or portable options, getting the size right is crucial for making sure your system matches your energy goals and lifestyle. In this guide, we’ll walk you through the typical solar panel sizes and wattage you’ll find, how portable options compare, and how to figure out what’s the best fit for your needs. Let’s dive in!
What’s the Common Solar Panel Size?
When you’re asking, “What size are solar PV panels?”, it’s important to understand both their physical dimensions and power output.
- Solar panel dimensions refer to the panel’s length, width, and thickness. This matters for installation space (like your roof!).
- Power output (measured in watts) tells you how much electricity a photovoltaic solar panel can generate under ideal conditions.
In South Africa, most residential solar panels are around 1.6 to 1.8 metres long and 1 metre wide, with a thickness of 3–4 cm. These are commonly 60-cell panels, which feature a 6×10 cell grid structure. The output of these panels generally ranges from 250 to 400 watts, making them ideal for most home installations.
Commercial solar panels, on the other hand, are larger and designed to meet higher energy demands. These panels are typically up to 2 metres long and are usually 72-cell panels arranged in a 6×12 grid structure. They offer a higher output, typically between 400 to 550 watts. These larger panels are perfect for bigger installations like businesses or large residential properties with more roof space.
You might also come across 96-cell panels (arranged in an 8×12 grid), which are even larger and offer higher outputs. However, these are generally too big for most residential roofs, and they are more commonly used in large-scale commercial installations where space is less of a constraint.
Here’s a quick breakdown of typical solar panel sizes available:
| Panel Type | Cell Layout | Dimensions (L x W) | Power Output | Best For |
| 60-Cell Panels | 6 × 10 Grid | 1.6-1.8 m x 1 m | 250W – 400W | Most residential homes; easy to install |
| 72-Cell Panels | 6 × 12 Grid | 1.8-2 m x 1 m | 400W – 550W | Homes with more roof space or commercial systems |
| 96-Cell Panels | 8 × 12 Grid | 1.6-2 m x 1-1.2 m | 450W – 600W | Larger installations and mainly commercial use |
How Large Are Portable Solar Panels?
As you see, rooftop solar panels, whether for home or commercial use, vary largely in sizes and wattage. However, once you install solar panels on your roof, their size isn’t something you need to think about anymore.
Portable solar panels, on the other hand, are a different story. Size matters a lot! If you’re using them for an RV, you might have limited roof space, or maybe you want something easy to carry and set up outside your campsite.
Let’s take a closer look:
- Small Portable Solar Panels (20W–100W): Compact and lightweight, these are ideal for charging phones, LED lights, and cameras. They are highly portable, often foldable, and perfect for short trips or light camping.
- Medium Portable Solar Panels (100W–200W): Larger and more powerful, these can charge multiple devices or power small appliances like a mini fridge. They typically measure around 1.5 meters in length and are great for extended camping or use with portable power stations.
- Larger Portable Solar Panels (200W–400W): Larger portable solar panels are ideal for powering RVs, larger camping setups, or running multiple devices simultaneously. These panels are bulkier but still designed to be portable, often foldable for easier storage.
| Panel Size | Dimensions (Unfolded) | Power Output | Best For |
| Small | ~1m x 0.3m | 20W – 100W | Charging phones, LED lights, small devices |
| Medium | ~1.5m x 0.6m | 100W – 200W | Powering small appliances, power stations |
| Large | ~2m x 1m | 200W – 400W | RVs, extended camping, high power needs |
How to Size a Solar Panel System for Your Home?
Now that you understand the basics, let’s talk about exactly how to determine the appropriate size of solar panels for homes. It depends on a few key factors, like your household’s energy consumption, the efficiency of the panels, your roof space, and how much sunlight falls in your area.
Here’s a step-by-step guide to help you through the general process:
1. Assess Your Energy Consumption
Begin by evaluating your household’s average energy usage:
Examine your electricity bills over the past year to account for seasonal variations. Add the kilowatt-hours (kWh) used each month and divide by 12 to find your monthly average.
In South Africa, the average single-family home uses anywhere from 200 to 1,000 kWh/month.
Let’s say you live in a household with 2 adults and 2 kids, and your monthly usage is 600 kWh, that works out to about 20 kWh per day.
2. Determine Peak Sunlight Hours
Solar panels don’t produce power 24/7—they rely on sunlight! South Africa gets about 4.5–6.5 peak sun hours/day, which varies by region. Find the average peak sunlight hours for your area and then use this data to understand how many hours per day your panels can operate at maximum capacity.
3. Calculate Required System Size
Now, use your energy consumption and sunlight data to determine the necessary system capacity:
System Size (kW) = Daily kWh ÷ Peak Sun Hours
Example: 20 kWh/day ÷ 5 sun hours = 4 kW system.
With a daily usage of 20 kWh and 5 peak sunlight hours, you’d need a system that can produce approximately 4 kW per hour.
4. Factor in Panel Efficiency and Losses
However, in the real world, things like shading, inverter losses, and temperature changes can impact the system’s performance, so you can expect around 15% in losses. To make sure you meet most of your energy needs, you can boost your system’s capacity to make up for those losses.
For example, if you need 4 kW, accounting for the 15% loss, you’d actually want to install about 4.6 kW.
5. Estimate the Number of Panels Needed
So, how many panels do you need for a 4.6 kW system? It depends on the wattage of the panels you plan to use:
Number of Panels = System Size (kW) × 1,000 ÷ Panel Wattage
For instance, the EcoFlow 400W Rigid Solar Panel is an excellent option, providing a high-efficiency output with a 23% conversion rate to sunlight, an IP68 waterproof rating, and a 10-year warranty.
Example: 4.6 kW system× 1,000 ÷ 400W per panel ≈ 12 panels.
So, for a 4.6 kW system, you would need around 12 EcoFlow 400W rigid solar panels.
To give you a clearer idea of how many panels you might need based on your energy consumption:
| Monthly Energy Consumption | Required System Size | Number of Panels (400W each) |
| 200 kWh/month | 1.5 kW | 4 panels |
| 400 kWh/month | 3.1 kW | 8 panels |
| 600 kWh/month | 4.6 kW | 12 panels |
| 800 kWh/month | 6.1 kW | 16 panels |
| 1,000 kWh/month | 7.7 kW | 20 panels |
6. Check Your Roof Space
But wait, you still need to check whether your roof has enough space to accommodate these panels. For our example with the 400W rigid solar panels, the EcoFlow solar panel specs are: 1.72m×1.13m, so you would need at least 23.28 m² of sunny roof area for a 4.6 kW system!
Once you know how much space you’ll need, make sure to measure your roof and check for obstructions like vents, chimneys, or skylights that could limit the usable area. Also, consult with a professional to make sure your roof can support the weight of the solar panels and mounting system.
What Other Factors Should You Consider?
When sizing and installing a solar panel system for your home, there are several important factors beyond just the number of panels and roof space. To ensure your system performs at its best and meets your energy needs efficiently, keep the following in mind:
Roof Orientation and Tilt
Your roof’s orientation (whether it faces north, south, east, or west) and its tilt angle play a significant role in how much sunlight the panels receive. In South Africa, panels should ideally face north for maximum exposure to the sun. The tilt of the roof can also affect efficiency—solar panels tend to perform better when angled at an optimal tilt, usually around 20°–30° depending on your location.
Shading
Shading from trees, buildings, or other structures can significantly reduce the efficiency of your solar system. Even partial shading can cause significant drops in energy production. To maximize energy capture, ensure that your solar panels are installed in a location with minimal shading during the peak sunlight hours (usually 10 AM to 4 PM).
Panel Efficiency
While the EcoFlow 400W Rigid Solar Panel offers an impressive 23% conversion rate, not all panels are created equal. Efficiency refers to how much sunlight a panel can convert into electricity.
Most modern monocrystalline panels range from 17% to 22% efficiency, with some premium models offering even higher performance. Since highly efficient panels convert more sunlight into power, you’ll need fewer panels or less roof space to meet your energy needs.
Maintenance and Durability
The EcoFlow 400W Rigid Solar Panel is built to last with an IP68 waterproof rating, which means it’s durable enough to withstand harsh weather conditions. However, regular maintenance is necessary to ensure optimal performance.
Clean your panels occasionally to remove dirt and debris, especially if you live in a dusty area. Inspect the panels periodically for any potential damage and ensure the inverter and battery storage systems are functioning well.
Solar Panel Warranties
When you buy a solar panel, you’ll be entitled to two types of warranties. They include product warranties and performance guarantees.
Product warranty covers the panel itself. If something goes wrong with the panel during the warranty period, the manufacturer will replace it. Most brands offer 10 years as standard.
Performance guarantee, on the other hand ensures your panels will keep producing a certain amount of energy over time. Most panels have a 25-year performance warranty, which means the energy output will gradually decrease, but they’re guaranteed to still perform at a reasonable level for the next couple of decades.
Conclusion
Choosing and installing the right solar panel size for your home is an exciting step towards energy independence and sustainability. By considering factors like your energy consumption, roof space, panel efficiency, and local conditions, you can ensure that your solar setup is tailored to your needs. With options like the EcoFlow 400W Rigid Solar Panel, which offers high efficiency and durability, you’re on the right path to reducing your carbon footprint while saving on energy costs.
Remember, every home is unique, and it’s important to consult with a professional installer to get a system that’s perfect for your situation. Start planning your solar journey today and take a step toward a brighter, more sustainable future!
FAQs
How big is a 400W solar panel?
A typical 400W solar panel is approximately 1.7 meters long and 1 meter wide, with a thickness of about 3–4 cm. The exact dimensions can vary slightly depending on the manufacturer, but most 400W panels are similar in size. It weighs between 18 to 23 kg and typically contains 60 to 72 solar cells.
How many solar panels do I need?
The number of solar panels you need depends on your home’s energy consumption, the efficiency of the panels, and the amount of sunlight your location receives. On average, a single 400W solar panel can generate about 1.5 to 2 kWh per day, depending on sunlight hours. For example, if you use 30 kWh of electricity per day, you’d need a system of at least 15 400W solar panels (30 kWh ÷ 2 kWh per panel).
How long do solar panels last?
Solar panels usually last around 25 to 30 years. Even after that, they still produce power, just at a bit lower efficiency. This means you can enjoy reliable energy for many years to come.