An **ampere-hour** is defined as a current of one ampere flowing for one hour. If you multiply the current in amperes by the time of flow in hours, the result is the total number of ampere-hours. Ampere-hours are normally used to indicate the amount of energy a storage battery can deliver.

Ampere-hours (Ah) are used to measure the capacity of a battery or the amount of electric charge that a battery can deliver over a certain period of time. The unit is commonly used in the field of electrical engineering and is used to describe the amount of energy stored in a battery.

For example, if a battery has a capacity of 50 Ah, it means that the battery can deliver a current of 1 ampere for 50 hours, or 5 amperes for 10 hours, or 50 amperes for 1 hour.

Ampere-hours are important because they allow engineers and users to determine the runtime of a battery-powered device or system. By knowing the battery capacity in ampere-hours and the average current draw of the device, one can estimate how long the battery will last before needing to be recharged or replaced.

Furthermore, ampere-hours are also used to compare the capacity of different batteries, which helps users choose the best battery for their specific application.

## Examples of ampere-hours

- A 12-volt car battery with a capacity of 50 ampere-hours can provide a current of 50 amperes for one hour or 5 amperes for 10 hours.
- A 6-volt deep cycle battery with a capacity of 200 ampere-hours can provide a current of 20 amperes for 10 hours or 100 amperes for 2 hours.
- A 48-volt lithium-ion battery with a capacity of 1000 ampere-hours can provide a current of 100 amperes for 10 hours or 500 amperes for 2 hours.
- A 24-volt lead-acid battery with a capacity of 300 ampere-hours can provide a current of 30 amperes for 10 hours or 150 amperes for 2 hours.
- A 12-volt marine battery with a capacity of 100 ampere-hours can provide a current of 10 amperes for 10 hours or 50 amperes for 2 hours.
- A 48-volt nickel-cadmium battery with a capacity of 500 ampere-hours can provide a current of 50 amperes for 10 hours or 250 amperes for 2 hours.

## Unit of Electric Current

**Electric current** is the flow of electric charge through a material. It is the rate at which electric charge flows past a point in a circuit. The flow of electric charge is typically carried by electrons, which are negatively charged particles.

The SI unit for current is the coulomb per second, or the ampere (A), which is an SI base unit:

1 ampere = 1A = 1 coulomb per second = 1 C/s.

The ampere (A) is defined as the rate at which electric charge flows through a surface per unit of time. One ampere is equal to a flow of one coulomb of electric charge per second.

The ampere is one of the seven base units in the International System of Units (SI) and is used to measure electric current in all practical applications. It is named after the French physicist André-Marie Ampère, who was one of the founders of the study of electromagnetism.