What is a watt (W): The watt is the unit of measurement for power, which is the rate at which energy is consumed or produced. It tells us how "fast" an appliance draws energy. A 50W small refrigerator consumes less power than a 2,000W water heater.
Formula: Voltage (V) × Current (A) = Power (W)
What is a watt-hour (Wh): The watt-hour is the unit of measurement for energy consumed or stored. It tells us how much energy an appliance needs to run for a specific amount of time, or how much energy a battery can hold.
Formula: Power (W) × Time (h) = Energy (Wh)
Consumption example:
| DEVICE | Watts | Use Hours | Consumption |
|---|---|---|---|
| LED Lights | 10W | 5 hours | 50Wh |
| 12v Fridge | 45W | 24 hours with interruptions | ~400Wh |
| Laptop | 60W | 3 hours | 180Wh |
| Cellphone Charger | 20W | 2 hours | 40Wh |
Autonomy example:
If you have a 100Ah battery at 12V, the stored energy is: 100Ah × 12V = 1,200Wh
See also ΥΠΟΛΟΓΙΣΤΗ ΑΝΑΓΚΩΝ ΕΝΕΡΓΕΙΑΣ to calculate the battery you need.