Why Do 1.5V Batteries Come in Different Sizes and Capacities?

[IMGOOD]

I wonder why they have so many different sizes for a 1.5V battery? Is it because some sizes are better in terms of performance?

 

[Averagesupernova]

If they were better in terms of performance then we'd just pick one size and use it. Physically larger batteries have more current capacity and amphours than smaller batteries. Things that use double or triple A cells require less current than something that uses D cells. Naturally, we would not put a pair of D cells in a camera because even though it may take more pictures it would be too bulky and heavy.

 

[Panda]

In addition the amphour capacity of a cell is only valid over a specific range, drawing too little current out of a battery gives reduced AH just as too much current does.
Putting expensive batteries in a clock is as efficient as putting cheap batteries in a CD player.
When designing equipment to operate from batteries a lot of time is spent ensuring the battery size and chemistry is suited to the operating current of the device.