Conversion (Electric Watts → Mechanical Horsepower)
There are a few different horsepower definitions, but the most common one is mechanical horsepower:
So:
Answer
500 W ≈ 0.67 hp (about two‐thirds of a horsepower)
Note
This is a power conversion — not energy stored or light output.
Solar ceiling lights are usually rated in watts of electrical power input, not directly in horsepower.
Horsepower is mostly used for motors and engines; for lights, watts is the standard.
If you meant something else (e.g., higher performance comparison, battery requirements, or solar panel sizing), tell me more!