Batteries are a vital component in fighting the Taken. They are used to replenish light sources such as flashlights and need to be inserted when the flashlights current batteries are depleted by prolonged use of the boosted beam. Battery power does however slowly regenerate over time. More powerful lithium batteries are also available for use. Batteries are found all over Bright Falls but many are left in caches by Cynthia Weaver. Only twenty spare batteries can be carried at one time. The standard battery packs will replenish 2 spare batteries, while lithium will restore 4, and the blue battery packs in The Signal and The Writer DLCs will restore 2 as well as 4.
- The batteries and flashlights used in the game are Energizer branded. Remedy Entertainment teamed up with Energizer to hopefully promote their products and make the game seem more realistic. However, in both The Signal and The Writer DLC's, the model of the batteries have been changed and they have a fictional name on their covers.
- Putting 100 batteries into your flashlight will net you the "Energized!" achievement.