Solar quotes are full of letters. Here is what they mean, in plain words.
The water tank picture
Think of power like water:
- kW / kVA = how wide the tap is (how much flows at once)
- kWh = how much water is in the tank (how much you have in total)
The words
| Word | Means | Used for | Example |
|---|---|---|---|
| W (watt) | Power at one moment | Appliances, panels | Fan = 60W, panel = 600W |
| kW | 1,000 watts | Loads, panel arrays | 6 panels × 600W = 3.6kW |
| kVA | Inverter size | Inverters | 5kVA inverter |
| Wh / kWh | Energy over time | Batteries, daily use | 5kWh battery |
| Ah | Battery charge | Batteries | 100Ah |
| V | Voltage | Batteries, systems | 48V system |
kVA vs kW
kVA is a little bigger than kW for most inverters. A 5kVA inverter usually gives about 4kW to 5kW of real power. Check the datasheet.
Ah to kWh
Ah × Volts ÷ 1,000 = kWh
- 51.2V × 100Ah ÷ 1,000 = 5.1kWh
- 12V × 200Ah ÷ 1,000 = 2.4kWh
That is why a "200Ah battery" can mean very different things. Always ask for kWh.
Simple kWh examples
- A 100W fan for 10 hours = 1kWh
- A 1,000W iron for 30 minutes = 0.5kWh
Why it matters when buying
- Want to run an AC? Look at kVA.
- Want power all night? Look at kWh.
