Finding these items and completing the side quest Ancient Armory will unlock the powerful Shield Weaver armor, which renders Aloy nearly invincible for a time while wearing it. The power cells are presented below in the chronological order they can be obtained in during the main quest line.
The first Power Cell can actually be found while exploring the open world after completing the prologue as Young Aloy. Return to the ruins where you found your Focus device and retrace your path through the barracks and down the stairs until you come to a closed door.
Pry open the door ahead of you and move through the offices to head back upstairs. At the top of the steps you’ll find a room with a doorway blocked by rock formations on your right – use your spear to smash through the rocks and collect the power cell off the desk.
The next Power Cell can be found in the All-Mother Temple in Mother’s Watch during the quest Womb of the Mountain, right after you complete The Proving. After finding your equipment and speaking to Matriarch Teersa, cross the hall to the locked door before following her out of the stronghold.
Next to the locked door is an open ventilation duct – move through it to enter the room beyond the door and collect a Power Cell.
If you did not collect the Power Cell during the quest you can return to Mother’s Watch at night to get back into the All-Mother Temple. If you go during the day the gate will be locked. NOTE: If you fast travel to Mother’s Watch you’ll need to walk/run to, and over, the bridge outside of town before the gate will open.
The third power cell can be found in Maker’s End, initially during the story quest of the same name. Once you’ve scaled the F.A.S. building all the way up to Faro’s Office – near the end of the mission – you’ll want to scale the tower at the east end of the office to the very tip-top of of the skyscraper.
Pick up the power cell and rappel back down.
The next Cell can be collected starting in the mission at and called the Grave Hoard. After descending down into the ruins, you’ll need to open an electronic lock by resetting three mechanisms to continue the mission.
Once the lock has been opened, you’ll find this power cell lying on the ground on the other side of the door.
The final power cell can be found in the ruins during the mission The Mountain That Fell. After speaking to Sylens in his workshop, climb down the elevator shaft and rappel down into the ruins.
Before following your objective marker to the right, turn left and walk north. Climb up the rubble ahead of you and head into the blue-lit cave ahead of you.
On a shelf in the back room you’ll find the final power cell.