The capacity of batteries is typically specified in terms of the total amount of electrical charge it can store. The unit of measurement for battery capacity is usually either ampere-hours (Ah) or milliampere-hours (mAh). Here's a brief explanation of these units:

Ampere-Hours (Ah):

• One ampere-hour is equal to the flow of one ampere of current for one hour.
• It is a larger unit and is commonly used for larger batteries, such as car batteries or deep-cycle batteries.

Milliampere-Hours (mAh):

• One milliampere-hour is equal to the flow of one milliampere of current for one hour.
• It is a smaller unit and is commonly used for smaller batteries, such as those in smartphones, cameras, or other portable electronic devices.

Battery capacity (AH) is defined as a product of the current that is drawn from the battery while the battery is able to supply the load until its voltage is dropped to lower than a certain value for each cell. Capacity of batteries usually expressed in Ampere Hour (AH).