The car has 3 power-on states

In a car, there are three power ON states: “AC”, “IG”, and “START”.
OFF is a state in which the electricity that drives the electrical components of the car does not pass, and the engine is not running.
ACC is an abbreviation for Accessory, an abbreviation taken from the first three letters of an English word. Also known as an accessory switch, it allows electricity supplied from the auxiliary battery to pass through only a small portion of the vehicle.
IG is an abbreviation for ignition, and electricity flows through most parts of the car. Starters, air conditioners, wipers, blinkers, and power windows for starting the engine are also typical examples of things that operate in the IG state.
START means the engine is running. All the parts in the car are switches that start moving.
For cars where you insert the key into the key cylinder and turn it, four characters such as OFF, ACC, IGON, and START are engraved on the cylinder. I understand.
Now that the push-type engine start switch has become mainstream, the difference between ACC and IG has become difficult to understand visually.

Although there are some exceptions,Pressing the start switch once without stepping on the brake will enter the ACC state, pressing it twice will enter the IG state, and pressing the start switch while stepping on the brake will enter the START state.
What devices can be used with ACC power?

When ACC is turned on, power supply ports such as navigation, audio equipment, ETC in-vehicle equipment, cigar sockets and USB terminals are energized even when the engine is not running.Regarding smartphone charging and navigation, it is possible in the ACC state without starting the engine.
In this way, the things that work with ACC are limited to things that work with very little power even in cars.
Starting the engine of a car is a movement that uses a large amount of electric power.
If you start the engine one by one and immediately turn it off immediately after setting the navigation system in a short time, the load on the battery will increase. Therefore,An ACC state is provided so that some devices can be operated without starting the engine, which consumes a large amount of power.That’s it.
Car accessory stores carry many electrical components that can be retrofitted, such as drive recorders, ETC in-vehicle devices, navigation systems, and audio systems.
Among them, drive recorders and portable navigation systems can be installed relatively easily just by connecting wires, but looking at the instruction manual,“Please connect ○○ to the ACC power supply.”There is also a note of caution. Why?