D size batteries are cylindrical in shape and have an electrical contact at each end. Positive contact may be recognised by a noticeable metal cap while the negative contact is flat. D size batteries are commonly used in applications that require an extended running time or high current drain. Due to its size, these batteries are ideal for large flashlights, megaphones, products that use electric motors etc.
Rechargeable D batteries are a better option than standard D batteries as they usually have a bigger capacity and can be used multiple times after proper recharging.
The physical size of the D battery is:
Diameter – 33.2 mm (1.3 inches)
Length – 61.5 mm (2.42 inches)