# What Is An Ampere-hour?

An ampere-hour is a unit of electric charge. It is represented by Ah. The ampere-hour is not part of the International System, since the hour is not either.

The ampere-hour indicates the amount of electric charge that passes through the terminals of a battery (or an electrical conductor) providing an electric current of 1 ampere (A) for one hour (h).

The ampere-hour is used to measure the capacity of a battery, that is, the amount of electricity it can store during charging and return during discharge.

A battery that has, for example, a capacity of 100 Ah, theoretically can give a current of 10 amps for 10 hours, or 1 amp for 100 hours.

At a practical level there are certain performance losses conditioned by the battery discharge rate, the faster a battery discharges, the more energy is lost due to internal resistance. Therefore, the load capacity is usually given with reference to a standard discharge time (10 or 20 hours), and for a specific final voltage.

The Faraday constant is used in electrochemical calculations. The Faraday constant is the charge in one mole of electrons, approximately equal to 26.8 amps per hour.

## How many Coulombs is an ampere-hour equivalent?

One hour of amps equals 3,600 coulombs (amp-seconds) of electrical charge transferred to a constant current of 1 amp for 1 hour, that is. In 1 second at 1 amp, current will flow 1 load pending.

The unit of electric charge in the International System is coulomb C. Coulomb is a derived unit that is defined in terms of the ampere: 1 coulomb is the amount of total electric charge that passes through a cross section of a conductor through which a electric current of one ampere for one second.

## What is the amp-hour used for?

The Ampere-hour is used in batteries, in solar batteries or in electric batteries in general to indicate the capacity. In automobile batteries it is maintained that the 12 V battery must be capable of supplying a discharge electric current of 1 / 20º of the nominal capacity indicated in A · h for 20 hours at a temperature of 25 ° C at a voltage higher than the cutoff which is 10.5V.

The amp-hour is also frequently used in measurements of electrochemical systems, such as electroplating.

The milliampere-second (mA · s) is a unit of measurement used in X-ray imaging, imaging, and radiation therapy. This amount is proportional to the total X-ray energy produced by a given X-ray tube operated at a particular voltage. The same total dose can be administered in different periods of time depending on the current of the X-ray tube.

## Examples in which the unit ampere-hour is used

- An AA-size dry cell has a capacity of approximately 2 to 3 amp-hours.
- The average smartphone battery generally has between 2,500 and 4,000 milliamps-hour of electrical capacity.
- Car batteries vary in capacity, but a large car powered by an internal combustion engine would have a battery capacity of about 50 amps per hour.
- Since one hour of amps can produce 0.336 grams of aluminum from molten aluminum chloride, producing one ton of aluminum requires a transfer of at least 2.98 million hours of amps.

Last review: March 28, 2020