Batteries appear throughout all games in various locations, usually nearby electronic devices, such as radios, Walkie-talkies, etc. They're mostly found one at a time, but, rarely, some areas contain two batteries in the exact same spot. Depending on the difficulty the player chooses, the amount of batteries that can be carried changes, as well as the amount that can be found throughout the game. A maximum of ten batteries can be held on Normal difficulty, five on Hard and two on Nightmare and Insane. The battery distribution across various difficulties applies to all games in the series. All protagonists start off with two batteries on Normal difficulty and only one on anything above that, with the exception of Waylon Park who always starts off without a single battery.
In Outlast 2, when Blake Langermann gets captured by Nick and Laird, he will lose his camcorder, all batteries and bandages. In addition, if the camcorder has full battery power, a quarter of it will be automatically drained after it is stolen by Laird.
- When playing Outlast on anything above the normal difficulty, the player starts off with only a single battery, yet the introductory cut-scene remains unchanged, still showing Miles inserting two batteries into the camcorder.
- The game files for Outlast contain models for a pack of three to four batteries at the same spot that were not included in the final version of the game.
- In the first demo version of Outlast, the player starts off with four batteries instead of two, and can carry up to twenty batteries, four of which are reloaded at once. This can still be seen in the retail version for a brief moment; by toggling the camera, the battery counter will display 4/20 regardless of how many batteries the player has.
- The batteries closely resemble +AA batteries of Duracell brand, but with reversed colors.