What is the battery life of the PowerBook G3 models using single and dual batteries?

One of feature of the PowerBook G3 models that enthusiasts still treasure -- or at least remember fondly -- is that the dual "hot swappable" bays make it easy to pop in dual batteries for runtimes that remain entirely respectable a decade later (as of the date last updated).

The Apple estimated battery life of each model with single and dual batteries is provided below:

PowerBook G3 Battery Life	Single	Dual
G3/250 (Original)	2-4 Hours	N/A
G3/233 (Wallstreet)	3.5 Hours	7 Hours
G3/250 (Wallstreet)	3.5 Hours	7 Hours
G3/292 (Wallstreet)	3.5 Hours	7 Hours
G3/233 (PDQ - Late 1998)	3.5 Hours	7 Hours
G3/266 (PDQ - Late 1998)	3.5 Hours	7 Hours
G3/300 (PDQ - Late 1998)	3.5 Hours	7 Hours
G3/333 (Bronze Keyboard/Lombard)	5 Hours	9-10 Hours
G3/400 (Bronze Keyboard/Lombard)	5 Hours	9-10 Hours
G3/400 (Firewire/Pismo)	5 Hours	9-10 Hours
G3/500 (Firewire/Pismo)	5 Hours	9-10 Hours

There no doubt still are those who wish Apple's current notebooks made it possible to pop out an infrequently used optical drive, for example, and pop in a second battery. Although it seems unlikely that this will become a possibility in future Apple designs -- it's more challenging to design systems that are as thin as possible and that still can support "swappable" bays -- but long-term Mac users may choose to dream.

Despite the vintage of the PowerBook G3 models, site sponsors Other World Computing and Operator Headgap Systems both carry replacement batteries (as of the date last updated).