How to Determine if a Cigarette Lighter is 24V or 12V?

[LeJackson]

The most straightforward method is to use a multimeter to measure the voltage between the two terminals of the car battery or to measure the voltage between the center and the side of the cigarette lighter socket. The car battery will also have markings indicating the voltage. Vehicles with gasoline engines typically use 12V, while diesel engines use 24V. Most small and medium-sized cars have 12V batteries.