For some laptop systems, the laptop manufacturers, such as Fujitsu
& Dell, offer a battery that can be used in the modular bay
(optical drive media bay such as DVD/CD drive bay) to extend your
notebook’s battery life over the single battery configuration. This
enables the use of two batteries for a laptop and potentially extends
the available run time.
If a secondary modular bay battery is installed, it will be used
first, and then the system automatically switches to the primary
battery. This is a deliberate design to allow the most amount of run
time to remain in the primary battery in case the modular bay battery
is removed and replaced with an optical drive.
This is a 48 WHr 6-Cell Secondary Modular Bay Battery for Dell.
Dell 4R084 Secondary Modular Bay Battery
Part#: Dell 4R084 (Secondary Modular Bay Battery)
Capacity: 48 Whr
Size: 5.17″ x 5.66″ x 0.57″
Dell Part Numbers: 312-0102, 312-0085, 4R084, 5P171, 0M787, 7P806, 9X001, 312-0069, 312-0122, 310-4345, 310-9124.