Why is a Battery rated in Ah and not in VA?

Why is a Battery rated in Ah and not in VA?

A battery has a rating in ampere-hours (Ah) rather than in volt-amperes (VA) because Ah represents charge capacity, (or) how much energy the battery can hold, whereas VA represents apparent power.

The main factors include:

  • Energy Storage
  • Voltage-Independent
  • Constant Voltage
  • Load Characteristic

Energy Storage

Batteries chemically store energy and then discharge it as electrical energy. The ampere-hour value indicates how much charge (current over time) the battery can provide before it is entirely depleted. It is directly related to the battery’s ability to store energy.


The Ah rating is unaffected by the battery’s voltage. A higher voltage battery with the same Ah rating can supply the same charge, but with more power.

Constant Voltage

Unlike in alternating current (AC) circuits, where volt-amperes (VA) account for power factor, batteries discharge at a nearly constant voltage. Watts are just the product of voltage & current.

Load Characteristic

The VA rating is particularly important for AC circuits and loads in which the voltage and current are not in phase. Because batteries provide direct current power, the volt-ampere idea is less appropriate.

In summary, ampere-hours (Ah) are directly related to a battery’s charge capacity, and this is its primary feature. VA is more appropriate for representing apparent power in AC circuits than for battery rates, which work on DC power principles.