# Why Battery rated in Ah (Ampere hour) and not in VA?

DWQA QuestionsCategory: Basic of Electrical EngineeringWhy Battery rated in Ah (Ampere hour) and not in VA?
Guru ji asked 7 years ago
Ranui answered 7 years ago

Battery stores charge in the form of chemical energy and then converts it into electrical energy to utilize for a specific time. The amount of available charge is the capacity of a cell or battery which may be expressed in Ah (Ampere-hour). Moreover, in a charged battery, the numbers of molecules are limited to create a flow of electron in electric circuits, so, there must be a limited number of electrons in a cell/battery which they motivate through a circuit to fully discharge.

Now we have the option to rate the battery capacity in Number of flowing electrons for a specific time, but, it would be a headache, because there are a vast number of electrons in it.  So we have another option (1C (Coulomb) = 6.25 x 1018 electrons, or 6,250,000,000,000,000,000 electrons.
In addition, 1A (Ampere) = 1 coulomb of electrons per second and,
1h = 3600 Seconds
Therefore;
1Ah = (1A) x (3600s) = (C/s) x (3600s) = 3600 C.
∴ A (1 Ampere) = 1 Coulomb per second = C/s

But,
Why make up a new unit for battery capacity rating when an old one unit is doing just fine? L
Of course! To make your lives as technicians and students more difficult.
As they do for electricity units… i.e. 1 Unit of Electricity = 1kWh = 1 board of Trade Unit…

Bhymi answered 7 years ago

Battery stores charge in the form of chemical energy and then converts it into electrical energy to utilize for a specific time. The amount of available charge is the capacity of a cell or battery which may be expressed in Ah (Ampere-hour). Moreover, in a charged battery, the numbers of molecules are limited to create a flow of electron in electric circuits, so, there must be a limited number of electrons in a cell/battery which they motivate through a circuit tofully discharge

Meetu answered 7 years ago

The amp-hour is a unit of battery energy capacity, equal to the amount of continuous current multiplied by the discharge time, that a battery can supply before exhausting its internal store of chemical energy,and this cannot be measured by VA.