Solar and inverter size calculator
Tired of NEPA? Tell us what you want to keep running and for how long. You get a starting estimate for the inverter, battery and solar panels, in the same units shops and installers use. Change any number to match your own appliances.
| Appliance | Watts each | How many | Hours a day |
|---|---|---|---|
| LED lights | |||
| Standing or ceiling fans | |||
| Television | |||
| Refrigerator(motor) | |||
| Chest freezer(motor) | |||
| Laptop | |||
| Wi-Fi router | |||
| Phone chargers | |||
| Air conditioner (1 HP inverter)(motor) | |||
| Water pump (0.75 HP)(motor) | |||
| Electric iron |
Your starting estimate
- Inverter
- 1 kVA
- 48 V system
- Battery
- 6.5 kWh
- about 135 Ah at 48 V
- Solar panels
- 1.7 kWp
- about 5 panels of 400 W
- Daily use
- 5.21 kWh
- 690 W if everything is on
Assumptions: 80% of the battery is usable (lithium), 90% inverter efficiency, 4 peak sun hours, 75% panel performance, 80% of the load running at once, and a 3x start-up surge for motors. Lead-acid batteries can only be used about half as deeply, so you would need roughly twice the capacity. Always match the battery voltage to the inverter you buy.
What next?
Take this estimate to a few installers and ask each to confirm it in writing. Browse our free directory of solar installers, and read the solar guide first so you know what to ask.
This guide is general information, not engineering, electrical or financial advice. Have a qualified, experienced installer assess your home or business, and follow local safety rules and the supplier's instructions.
Frequently asked questions
What size inverter do I need for my house in Nigeria?
Add up the watts of everything you want to run at the same time, allow some headroom, then pick the next standard size. Appliances with motors, such as fridges, pumps and air conditioners, draw extra power for a moment when they start, so they can push you to a larger inverter. This calculator does that arithmetic for you.
How big a battery do I need?
Battery size depends on how many hours you want to run your appliances when there is no light. Multiply the watts by the hours, then add allowance for the part of the battery you cannot use and for inverter losses. Lithium batteries can usually be used deeper than lead-acid, so they need less nominal capacity for the same backup.
How many solar panels do I need?
Panels must produce the energy you use in a day. Nigeria gets roughly 4 to 6 peak sun hours a day, and real systems deliver about 75% of the panel rating after losses. The calculator uses a cautious 4 hours and 75%.
Is this calculator accurate enough to buy from?
It is a planning tool that gives a sensible starting point so you can ask better questions. It cannot replace a site visit, because roof space, shading, cable lengths, appliance start-up currents and battery type all matter. Ask an installer to confirm the design in writing.