Answer by
crabfoot (253)

Dividing the wattage of the bulb by the voltage of the system gives the current drawn in Amperes. So, for a 60W bulb in a 12V system, the draw will be 60/12 = 5 amps. For a 100W bulb in a 12V system, the draw is 100/12 = 8. 3 amps.