The operating voltage of a vehicle should be a range but not a fixed number, when we say car’s voltage is 12VDC, which means the voltage range should be kept between 10~18 V(18V is the highest possible peak voltage) and the average is approx. 14.6V, usually the standard of our products is 14V for CAR, motorcycle, scooter, some boats( we still call 12V in public); 28V for truck and some boats. ( we still call 24V in public)
Therefore, when we talk about bulb wattage, it is also a range because
WATTAGE( W) = Current (A) x Voltage(V)
For example, when the current is 0.2A @ 13V, the Watt=0.2×13=2.6W, the reason we do not rate wattage because a LED auto bulb is made of various electrical components such as resistors, capacitors..etc. A maker can adjust the current easily by controlling the value of inside component to enhance the higher power and brightness in short time but lower reliability and life span. Wattage data for brightness for LED BULB in fact is meaningless.