HOW MANY SOLAR PANELS, BATTERIES AND INVERTERS DO YOU NEED IN NIGERIA

WHY MOST NIGERIANS GET SOLAR SIZING WRONG

Let’s be honest. Most people in Nigeria don’t get solar wrong because they are careless. They get it wrong because nobody explains it clearly.

So what happens? You buy a system, and by 10pm your batteries are dead, your freezer is off, and you are back to running your generator. Or your inverter keeps tripping because of overload. Or worse, you spend ₦3 million and still need your generator every night.

This guide fixes that. We will show you exactly how to calculate the right solar system sizing in Nigeria, step by step, with real examples for real Nigerian homes and businesses. No guesswork, no overspending, no surprises.

If you are about to spend ₦500,000 to ₦5,000,000 on solar, this is the most important page you will read.

We will walk through four steps: calculate your load, choose the right inverter, size your battery bank, and work out how many solar panels you need. Then we will show you complete worked examples for common setups, from a self-con to a medium-sized office.

STEP 1: CALCULATE YOUR TOTAL LOAD IN WATTS

Before you buy anything, you need to know exactly how much power your appliances consume. This is the foundation of any solar calculator for Nigeria, and it starts with a simple list. Check the nameplate sticker on the back or bottom of each appliance. It will show the wattage in watts (W) or kilowatts (kW). If it shows amps instead, multiply the amps by the voltage (usually 220V) to get watts.

Write down every appliance you want to run on solar, along with its wattage. Then add them up. This total is your load.

Here is a typical Nigerian household example:

Total load: 750W

Important: if any of your appliances have a motor (fridges, freezers, ACs, blenders, water pumps), the startup surge can be 2 to 3 times the rated wattage for a few seconds. A freezer rated at 245W may draw 600W or more when the compressor kicks in. Keep this in mind when choosing your inverter size in the next step.

STEP 2: CHOOSE THE RIGHT INVERTER SIZE

The inverter converts the DC power stored in your batteries into the AC power your appliances use. Choosing the right size is critical. Too small, and the inverter will overload and shut down. Too close to your load, and you have no headroom for startup surges.

The rule: your inverter should be at least 1.5 to 2 times your total load.

For solar systems, always choose a pure sine wave or solar hybrid inverter. Modified sine wave inverters are cheaper, but they cannot run sensitive electronics like laptops, decoders, and inverter-compressor fridges reliably. If you are not sure what this means, read our guide on pure sine wave vs modified sine wave inverters.

Here is how to match your load to the right Mercury inverter:

For our 750W example load, the Mercury 2.4kVA (24V system, 1,920W continuous) is the right fit. It gives you plenty of headroom above your 750W running load and handles freezer startup surges without breaking a sweat. Your inverter’s system voltage (12V, 24V, or 48V) determines the minimum number of batteries you need, which brings us to the next step.

STEP 3: CALCULATE YOUR BATTERY BANK SIZE

Your batteries store the energy that powers your home when there is no sunlight, which is typically from around 6pm to 6am in Nigeria. The question is: how many batteries do you need, and how big should they be?

Two things determine your battery bank size:

• System voltage: Your inverter’s DC voltage determines how many batteries you connect in series. A 24V inverter needs 2 batteries (2 x 12V = 24V). A 48V inverter needs 4 batteries (4 x 12V = 48V).
• Backup hours: How many hours do you want to run your appliances at night without solar or NEPA? Most Nigerian homes need 5 to 8 hours of backup (6pm to midnight, or 6pm to 2am).

Here is the formula for calculating how many hours your battery bank will last:

Let us break down each part of this formula:

• Battery Voltage x Battery Ah: This gives you the total energy in watt-hours (Wh) stored in your battery bank. For two 12V 200Ah batteries in series: 24V x 200Ah = 4,800Wh.
• Depth of Discharge (DoD): You should never drain a battery to zero. For GEL and AGM batteries in Nigerian conditions (daily cycling, poor grid), use 80% DoD. For lithium (LiFePO4) batteries, you can safely use 95% DoD.
• Inverter Efficiency: Every inverter loses some energy as heat during the DC to AC conversion. Use 85% (0.85) for a realistic estimate.
• Load in Watts: Your total appliance load from Step 1.

Worked Example: 750W Load with 2x 200Ah GEL Batteries

So two 200Ah batteries on a 24V system will power a 750W load for about 4.3 hours. That covers 6pm to roughly 10:15pm. If you need the full night (8 hours of backup), you have two options: reduce your load at night (switch off the freezer, use fewer lights), or add more batteries in parallel.

Adding a second parallel string (4 batteries total, still 24V but now 400Ah) doubles the backup time to roughly 8.7 hours.

For a quick reference, here is a battery backup table for common loads:

STEP 4: CALCULATE HOW MANY SOLAR PANELS YOU NEED

Your solar panels have two jobs. First, they need to generate enough power to run your appliances during the day. Second, they need to recharge your batteries so you have backup at night. You need enough panels to do both.

Part A: Panels to Run Your Daytime Load

Start with your load and multiply it by the number of hours you will use those appliances during the day:

Add 30% to account for real-world losses (dust on panels, cable resistance, charge controller losses, cloudy spells):

Now divide by the average peak sunlight hours in your area. In Lagos, this is about 4 hours. In Abuja and the northern states, you get 5 to 6 hours. In the rainy season across southern Nigeria, budget for 3 to 3.5 hours.

Part B: Panels to Recharge Your Batteries

Your batteries also need to be fully recharged each day. Calculate the energy you used from the batteries overnight:

Add 20% for charging losses (the charge controller and battery chemistry are not 100% efficient):

Total Solar Panels Required

Now here is the part most guides get wrong. You do not simply add Part A and Part B together, because while the sun is out, your panels are doing both jobs simultaneously. The correct approach is to take the larger of the two numbers and add a portion of the smaller one.

If this feels confusing, don’t worry. In real life, most Nigerian homes fall into simple ranges: 3 to 6 panels for a small flat, 6 to 10 panels for a standard 2 to 3 bedroom, or 10 to 16 panels for heavy loads and offices. We will show you complete examples below. But if you want to do the exact math, here it is:

Using 400W monocrystalline panels (the current standard for Nigerian residential solar in 2026):

If you want extra margin for the rainy season and overcast days, go with 6 panels (2,400W total). This gives you a buffer that keeps your batteries topped up even during Harmattan haze or heavy cloud cover.

Peak Sunlight Hours by Region

Nigeria’s sunlight varies significantly between north and south, and between dry season and rainy season. Here are practical figures to use in your calculations:

WHAT SOLAR COSTS VS RUNNING A GENERATOR

Before we get into the sizing examples, let’s talk about the question every Nigerian asks: is solar actually cheaper than running a generator?

At current fuel prices, a typical petrol generator costs ₦1,100 to ₦2,700 per hour to run, depending on the size and load. A properly sized solar system, spread across its lifespan, costs the equivalent of ₦120 to ₦250 per hour. That is 5 to 10 times cheaper, and fuel prices are only going up.

This is why most of our customers stop using their generator within weeks of installing solar. The savings are not theoretical. They show up in your pocket every single month. For a detailed breakdown, read our generator cost vs inverter comparison.

QUICK SYSTEM GUIDE: WHAT SIZE INVERTER DO I NEED IN NIGERIA

Not everyone wants to run through the formulas. If you just want a fast answer, use this table to find where your home or office fits:

COMPLETE SIZING EXAMPLES FOR NIGERIAN HOMES AND BUSINESSES

Here are three worked examples covering the most common setups Nigerian customers ask about. Each one uses the same four-step process described above.

Example 1: Self-Con / One-Bedroom Apartment (Basic Comfort)

Total load: 375W

• Inverter: Mercury 1.5kVA Solar Hybrid (12V, 1,200W continuous). More than enough headroom.
• Batteries: 1 x 200Ah deep cycle battery (12V). At 80% DoD and 85% efficiency: backup = (12V x 200Ah x 0.80 x 0.85) / 375W = 4.4 hours. For 8+ hours, use 2 x 200Ah in parallel.
• Solar Panels: 3 x 400W monocrystalline panels (1,200W total). Sufficient for Lagos sunlight conditions.

Typical budget range: ₦800,000 to ₦1,400,000 depending on battery type and installation.

Example 2: Three-Bedroom Flat (Standard Nigerian Family)

Total load: 1,110W (with fridge and freezer compressor surges, peak draw can reach 1,800W briefly)

• Inverter: Mercury 3.5kVA Solar Hybrid (24V, 2,800W continuous). Handles the running load with enough headroom for compressor surges.
• Batteries: 4 x 200Ah deep cycle batteries (2 series x 2 parallel = 24V, 400Ah). Backup = (24V x 400Ah x 0.80 x 0.85) / 1,110W = 5.9 hours.
• Solar Panels: 8 x 400W monocrystalline panels (3,200W total). Enough to run the daytime load and recharge the batteries fully.

Typical budget range: ₦2,500,000 to ₦3,800,000 depending on battery type (GEL vs lithium) and installation complexity.

Example 3: Small Office / Shop (15 Staff)

Total load: 3,131W (peak with laser printer running can exceed 3,500W)

• Inverter: Mercury 5.5kVA Solar Hybrid (48V, 4,400W continuous). Sufficient headroom for the laser printer surge.
• Batteries: 8 x 200Ah deep cycle batteries (4 series x 2 parallel = 48V, 400Ah). Backup = (48V x 400Ah x 0.80 x 0.85) / 3,131W = 4.2 hours. For a full working day of backup, consider upgrading to a 10kWh lithium battery system.
• Solar Panels: 12 to 16 x 400W monocrystalline panels (4,800W to 6,400W total). The higher end if your roof gets partial shade or if you are in southern Nigeria with fewer peak sun hours.

Typical budget range: ₦4,500,000 to ₦7,000,000 depending on battery type, panel count, and installation. For systems this size, request a custom quote from our technical team.

COMMON SOLAR SIZING MISTAKES IN NIGERIA

At Mercury Direct, we have installed and sized thousands of inverter and solar systems across Lagos and Nigeria. The patterns are clear. These are the mistakes we see again and again. Avoid them and your system will perform as expected.

• Mistake 1: Ignoring startup surges. A freezer rated at 245W can draw 600W or more when the compressor starts. If your inverter is too close to your running load, these surges will trigger overload shutdowns. Always leave at least 50% headroom above your total load.
• Mistake 2: Using car batteries instead of deep cycle batteries. Car batteries are designed for short, high-current bursts (starting an engine). They are not built for the deep, repeated cycling that solar systems demand. They will fail within 3 to 6 months. Always use deep cycle or GEL batteries designed for inverter use.
• Mistake 3: Not accounting for rainy season. If you size your panels for dry season sunlight (5 to 6 peak hours), your batteries will not charge fully during the rainy season (3 to 4 peak hours). Size for the worst case, not the best.
• Mistake 4: Skipping the charge controller. Solar panels must be connected to your batteries through an MPPT or PWM charge controller. Without it, you risk overcharging and damaging your batteries. MPPT controllers are 15% to 30% more efficient than PWM controllers and pay for themselves quickly. All Mercury Solar Hybrid inverters have a built-in MPPT charge controller.
• Mistake 5: Running AC on an undersized system. A 1HP air conditioner draws 750W to 1,000W continuously, with startup surges up to 2,500W. Running AC on solar requires at minimum a 3.5kVA inverter, and your panel and battery bank must be sized accordingly. Do not try to “add AC later” to a small system.
• Mistake 6: Buying panels that are too small. In 2026, the standard residential panel is 400W to 550W monocrystalline. Older 150W or 200W panels take up the same roof space but produce far less power. You end up needing more panels, more mounting hardware, and more wiring for the same output.

QUICK REFERENCE: HOW MANY SOLAR PANELS FOR YOUR MONTHLY CONSUMPTION

If you know your monthly electricity consumption in kWh (check your NEPA meter or prepaid token receipts), you can estimate your solar panel requirement directly. This table assumes 4 hours of peak sunlight per day (Lagos) and 400W panels:

YOUR ROOF AND SOLAR PANEL PLACEMENT

Even with the right number of panels, poor placement will reduce your system’s output. A few things to consider:

• Panel direction: In Nigeria (close to the equator), panels should face south or slightly south-west for maximum afternoon sun. East-facing panels lose 10% to 15% of potential output.
• Shade: Even partial shade on one panel can reduce the entire string’s output by 30% to 50%. Trees, water tanks, and neighbouring buildings are the usual culprits. Walk your roof at different times of day to check for shadows.
• Roof space: A standard 400W panel measures roughly 2m x 1m. If your roof can fit 8 panels, that is 3,200W maximum. Factor this into your planning.
• Tilt angle: For most of Nigeria, a tilt of 5 to 15 degrees is ideal. Flat-mounted panels work, but a slight tilt helps rainwater wash away dust, especially during Harmattan.

If your roof space is limited, consider higher-wattage 550W panels. They cost more per unit but produce more power per square metre, which can be the difference between a system that works and one that falls short.

Not sure if your numbers are correct? That is normal. Most people get this wrong the first time, which is exactly why we offer free sizing consultations. Let us check your calculations before you spend a single naira.