The Nintendo DS contains a rechargeable lithium-ion battery with a capacity of 850 mAh. On a full four-hour charge, the factory 850 mAh battery lasts about 10 hours. (This decreases the more you charge it.) Battery life is affected by multiple factors including speaker volume, use of one or both screens, back lighting, and use of wireless connectivity. The biggest effect on battery life is caused by using the backlight, which can be turned off in the main menu screen, or in selected games (such as Super Mario 64 DS). The battery is designed to be removed only when it expires.
To sustain battery life in the midst of a game, users can close the Nintendo DS system, putting the DS in sleep mode that also pauses the game that is being played; however, closing the system while playing a Game Boy Advance game will not put the Nintendo DS into sleep mode; the game will continue to run normally, including the back light. Certain DS games (such as Animal Crossing: Wild World) also will not pause but the backlight, screens, and speakers will turn off. When saving the game in Pokémon Diamond and Pearl, Zoo Tycoon DS, SimCity DS, Tiger Woods PGA Tour, Mega Man Battle Network 5, or The Legendary Starfy, the DS will not go into sleep mode