Solar Load Calculator Nigeria: Inverter, Battery & Panel Size (2026)

A typical Lagos 2-bedroom flat with fans, a TV, a fridge, lights, laptops and a pumping machine needs a 2.5kVA inverter, about 5 kWh of lithium battery and five 450W solar panels. That costs roughly ₦2,200,000–₦3,600,000 installed at prices seen in October 2026. Use the calculator below to size the inverter, battery and panels for your own appliances and NEPA hours.

Solar load calculator: what size inverter, battery and panels do I need?

The calculator lists 12 common appliances with typical watts and is filled in for a typical 2-bedroom flat. To add an appliance, set its quantity above 0; set it to 0 to take it out. Change the watts if your appliance label shows a different figure. For anything not listed, such as a sewing machine or a barbing clipper, rename one of the two custom rows at the bottom. Then enter how many hours of NEPA light you get on an average day.

The calculator assumes everything with a quantity above zero could run at the same time, which is the safe way to size an inverter. If you never iron while the pumping machine is running, you can size slightly smaller. The cost range is a rough guide for budgeting, not a quote.

If the borehole is your biggest load, a DC solar pump that runs straight from its own panels can take it off the inverter completely; see our guide to solar pumping machine prices in Nigeria.

Leave security and compound lights out of this calculation if you can. Standalone units with their own panel and battery do not draw from your inverter at all; see current solar street light prices in Nigeria.

Heating appliances are the loads that catch people out. A bathroom water heater draws 1,500–2,000W on its own, more than a 1.5kVA inverter can deliver; our water heater price in Nigeria guide shows what inverter and battery size a heater needs.

What assumptions does the calculator use?

How do I calculate the inverter size in kVA?

Add up the watts of everything you want running at the same time. Multiply by 1.25 so the inverter is not working flat out, and so it has room for the short starting surge of fridges, freezers and pumping machines. Inverters are rated in kVA, and at a power factor of 0.8 each kVA delivers about 800 W, so divide by 800 and round up to the next common size.

Example: 1,520 W × 1.25 = 1,900 W. Then 1,900 ÷ 800 = 2.38 kVA, so you need a 2.5kVA inverter. Working backwards, a 5kVA inverter delivers about 4,000 W, which means a comfortable everyday load of about 3,200 W. Once you know your size, compare brands in our 3.5kVA, 5kVA and 10kVA inverter price guides, or see every size in our solar inverter price list.

How do I calculate battery size for NEPA outages?

First find your daily energy use: watts × quantity × hours for each appliance, added up. That gives watt-hours (Wh). The battery only has to cover the hours when NEPA is off, so multiply by (24 − grid hours) ÷ 24. Then divide by 0.9, because lithium (LiFePO4) batteries should only be drained to about 10%.

Your band matters. A Band A feeder promises at least 20 hours of supply, so the battery only covers about 4 hours. On Band D or E you may get 4–8 hours, so the battery has to carry most of the day. To turn Wh into amp-hours, divide by the battery voltage: 5,000 Wh is about 208Ah at 24V or 104Ah at 48V. Tubular and other lead-acid batteries should only be drained to about 50%, so you need roughly double the capacity. Our solar battery price guide compares the options, and our best solar batteries in Nigeria guide covers brands.

How many solar panels do I need in Nigeria?

Most of Nigeria gets around 4.5–6 peak sun hours a day, with the north sunnier than the south. We use a cautious 4.5 hours and take off 20% for heat, dust and wiring. So one 450W panel gives 450 × 4.5 × 0.8 = 1,620 Wh a day. Divide your daily Wh by 1,620 and round up. Homes in Kano, Sokoto or Maiduguri may manage with one panel fewer; homes in Port Harcourt or Calabar should not cut it fine.

What size solar system does a Lagos 2-bedroom flat need?

This is the example loaded in the calculator: a family flat in Lagos on about 8 hours of NEPA a day, so 16 hours on battery.

1. Load: 1,520 W × 1.25 = 1,900 W.
2. Inverter: 1,900 ÷ 800 = 2.38 kVA, so a 2.5kVA inverter. Many buyers step up to 3.5kVA 48V so they can add a freezer later.
3. Battery: 6,715 × 16 ÷ 24 = 4,477 Wh; 4,477 ÷ 0.9 = 4,974 Wh, so about 5 kWh of lithium. That is about 208Ah at 24V or 104Ah at 48V, so one 5 kWh pack fits.
4. Panels: 6,715 ÷ 1,620 = 4.1, so five 450W panels (2,250 W).
5. Cost: inverter ₦300,000–₦550,000 + battery 5 × ₦230,000–₦340,000 + panels 5 × ₦95,000–₦130,000, plus 15–25% for the rest = about ₦2,210,000–₦3,610,000.

What size inverter, battery and panels for common Nigerian homes?

For full system prices by size, including what installers in Lagos, Abuja and Port Harcourt charge, see our complete solar system cost in Nigeria guide.

What sizing mistakes should I avoid?

• Counting a fridge as 24 hours at full watts. The compressor cycles on and off, so 8–12 hours at rated watts is closer to reality.
• Ignoring starting surge. A 750 W pumping machine can pull 2,000 W or more for a second. Check the inverter’s surge rating as well as its kVA.
• Running ACs at night on batteries. One 1HP AC for 6 hours adds 5.4 kWh a day, which doubles the battery bank for most flats. Run ACs in the afternoon when the panels are producing.
• Sizing tubular or “London-used” batteries like new lithium. Lead-acid needs about twice the capacity, and second-hand packs rarely deliver their label rating.
• Shaded roofs. Shade from a water tank or a neighbour’s building can cut output sharply. Add a panel or move the array.

Still deciding whether solar beats your generator? Read generator vs inverter vs solar in Nigeria for the running-cost maths. If you mainly want to keep a freezer running, our solar refrigerator and freezer prices guide may save you money.

Frequently asked questions

What size inverter do I need for a 3-bedroom flat in Nigeria?

Usually 3.5kVA for fans, TVs, a fridge, a freezer, lights and a pumping machine. Add a 1HP AC and most homes need 5kVA. Enter your appliances in the calculator for a specific answer.

How many watts can a 3.5kVA inverter carry?

About 2,800 W (3,500 × 0.8). With the 1.25 safety factor, keep your regular load near 2,240 W.

How many batteries do I need for a 5kVA inverter?

Most 5kVA inverters are 48V, so you need at least four 12V tubular batteries in series, or one or more 48V lithium packs. How many depends on your night-time kWh, not the inverter size.

Why does the calculator use 4.5 sun hours?

It is a cautious figure that holds up in Lagos, Port Harcourt and the rainy season. Homes in the far north get more sun, so the same panels produce more.

Need a quote for the size you calculated? Visit our shop.

Sources

• World Bank Global Solar Atlas: Nigeria solar resource map
• Techpoint Africa: lithium battery prices in Nigeria
• Zit.ng: Felicity 2.5kVA 24V inverter listing
• Nigeria Housing Market: solar panel price list 2026

Last updated: October 2026. Prices are estimates seen in October 2026 and move with the naira exchange rate; confirm with the seller before you buy. This calculator gives a starting point, not an engineering design; have a qualified installer check your load before buying.