The AAA, AA, C and D are cylindrical batteries varying in size, power rating and intended applications. Manufacturers choose the battery that best fits the size and power needs of their products.
The AAA batteries are the smallest of the group at 10.5mm in diameter and 44.4mm tall. They progressively increase in size through AA and C to the largest, D, at 43.2mm diameter and 61.5mm high.
Intended Daily Use
Double and triple A batteries are designed for one hour of use per day. The C and D ranges are used in short bursts over longer periods, C batteries being used for four minutes per hour, for up to eight hours per day, and D for up to four minutes in every quarter hour, for a total of eight hours per day.
The AAA and AA batteries have average minimum lifespans of 5 1/2 and six hours, respectively. The larger C should last for at least 13 to 14 hours, and the D for about nine hours in total.
The lowest power ratings are AA and AAA batteries with a nominal 1120 and 2450 milliamp hours (mAh) each. C batteries are more powerful at around 7800 mAh . The D is the most powerful at 16500 mAh.