Every solar quotation in Nigeria lists three different units. Confusing them is the most common reason customers buy a system that does not meet their expectations.
kVA and kW: how much you can run at once
Power is the rate at which electricity is used. Inverters are usually rated in kVA (kilovolt-amperes). Appliances are rated in watts (W) or kilowatts (kW).
The two are related by the power factor of your loads. A practical rule is that an inverter can deliver around 80% of its kVA rating as real power — so a 5 kVA inverter supports roughly 4 kW of simultaneous load.
If you switch on more appliances than the inverter can supply, it will overload and shut down. This is why the peak load — everything that may run at the same time — determines inverter size.
kWh: how long you can run
Energy is power used over time, measured in kilowatt-hours (kWh). A 1 kW air conditioner running for 5 hours uses 5 kWh.
Batteries are rated in kWh. A battery’s usable energy is lower than its nominal rating because batteries should not be fully discharged. Lithium iron phosphate batteries typically allow 80–90% usable capacity.
kWp: how fast you recharge
Solar panels are rated in kWp (kilowatt-peak) — their output under standard test conditions. Real-world output is lower because of heat, dust, wiring losses and the angle of the sun.
Comparing quotations
When comparing two quotations, check:
- Inverter kVA against your peak load (with headroom for motor start-up).
- Usable battery kWh, not just the nominal figure, against your night-time needs.
- Solar kWp — is it enough to run daytime loads and recharge the batteries?
Our sizing calculator estimates all three from your appliance list.