Fusion core (Fallout 4)

Fusion core is an items type in Fallout 4.

Characteristics
Fusion cores are used to power and activate Pre-war suits of power armor. Each core provides roughly twenty minutes of power armor use based on activity; sprinting causes the power to drain much faster, whereas walking consumes less power.

Fusion core lifespan can be extended by 10% by collecting the Repair bobblehead, and by up to 100% by investing points in the Nuclear Physicist perk.

Locations

 * One can be found in the Museum of Freedom's lowest floor, Sturges asks the player character to retrieve it, but can be taken without getting the quest nonetheless.
 * Another is in ArcJet Systems in the room where the player character can restore power to the elevators.
 * Four can be found in the ammo box next to the safe in the ruined building with four burnt out suits of power armor during the "The Lost Patrol" mission for Brotherhood of Steel (Possibly random loot)*
 * One can also be found in the Mole rat den under the Red Rocket truck stop.
 * One is located in the basement of USAF Satellite Station Olivia.
 * Two can be found in Recon Bunker Theta, during the mission to recover the Brotherhood Holotapes in "The Lost Patrol"
 * One can be found in the office of Cambridge Polymer Labs, either by picking the master lock or successfully finishing the laboratories research (Which also nets you a new Power armor torso piece)
 * One can be found in Publick Occurrences upstairs under the bed in a suitcase.*
 * One can be found in the military crate at Robotics Disposal Ground and two can be looted from the if sentry bot is destroyed (or self destructs)*
 * One is located in Fort Hagen
 * One is located in Mystic Pines (Northeast of Lexington) in a room towards the back. The door to this room is locked (Advanced) and requires 1 point in Locksmith perk to pick.
 * One can be found at the Starlight Drive In in the building behind the screen, with a locked (Novice) door.
 * One can be found at Mass Fusion containment shed. It is recommenced you take measures to counter the Rads you will gain from walking through here. After hacking the terminal (Novice) upstairs from the security door, there is a gated cage of radioactive waste. Open the gate and walk down the rows of waste until you get to the end. There is a Feral ghoul (Fallout 4) and a container on the back wall with the fusion core.*
 * One can be found at the bottom of the Super-Duper Mart in a generator.
 * One can be found in College Square in the building opposite the hanging man, near the wooden bridge. Go up the stairs, it's on the desk by the toolbox.
 * Two cores can be looted from a dead Sentry bot (Fallout 4).
 * Up to five can be found in The Castle's Armory (including from The Sarge sentry).
 * Another two can be found in a footlocker in the adjacent room to the chems store at The Castle*
 * Several may be found at Chestnut Hillock Reservoir in an ammo box outside the building, by the couch and lantern to the left of the door.*
 * Four can be found in Doc Crocker's house.
 * Three can can be found at the Federal ration stockpile. One is inside a generator room behind a locked door (Novice). One is outside in an external generator room shed above the facility. There is unoccupied power armor with a full fusion core just in front of the facility and can be looted from it if you sneak up to it.
 * Two can be found at Greenetech Genetics on the top floor behind a security door. (Master)
 * One can be found in a trash can at West Roxbury station*
 * One can be found on a mutant swan at Swan's Pond, the swan has a large amount of HP and can kill you in a few hits, so be prepared.
 * Two can be found at Wilson Atomatoys Corporate HQ. First one is next to a ammo box at the entrance outside, for the second one after you first enter go to the room on the left it will be in a generator to the right. Beware of super mutants.
 * Four can be found on a rooftop opposite South Boston police department in an Ammo Box.*
 * One can be found on the main road north of Poseidon Reservoir at a military checkpoint, in a power armor.
 * Two can be found at Four Leaf Fishpacking plant one in a generator and the other behind a security gate, on a shelf.
 * Three can be found at General Atomics factory, in the safe after completion of the three Quality Assurance trials.*
 * Several (4?) may be found in a container in the camp surrounding the Bunker Hill monument, but they are marked as owned by an NPC and must be stolen as a result.*
 * Four can be found at Med-Tek research on top of the parking garage
 * Two can be bought at Diamond City Surplus
 * Five can be bought at Commonwealth Weaponry in Diamond City
 * One can be found east of Finch Farm, in the pump station across the river. Pass code is written on the wall, below the door.
 * Four can be found in the Revere satellite array next to Scribe Faris.
 * Erin Combes will give you one for finding Ashes in the quest Here Kitty, Kitty.
 * One can be found inside Recon Bunker Theta
 * Four can be found at Gwinnett brewery in a ammo box upstairs (to get up there you have to go along pipes).*
 * Two can be stolen off suits in the Prydwen's maintenance bay by sneaking behind them. Note if Dense is nearby - he will disapprove of this.