If you're getting it mid quest, it's through two doors after you wake up, and then a small vent-like tunnel you have to crouch to get through, that's on your right. Power Cell location 2: All-Mother Temple - You can access this either during or at any time after the quest Womb of the Mountain, after the Proving. It's about three quarters of the way through the Ruins, and Aloy will give you a little dialogue wondering if she can somehow get through now she's older when you get close. The Power Cell is located the other side of some stalactites and stalacmites - you can see it through them, but need to smash them with your Lance to get through.
![horizon zero dawn cauldron sigma horizon zero dawn cauldron sigma](https://oyster.ignimgs.com/mediawiki/apis.ign.com/horizon-zero-dawn/1/1f/Cauldronrholocation2.jpg)
We suggest you drop right down to the lowest level when re-entering, and running through it in the same order as you did with young Aloy at the start of the game. It's easy to get caught going in circles through this cavern, especially as you can re-enter it on a different level. Head back to the location of your first steps with Aloy, which is marked as Ruins on your map with a green symbol, just east of Mother's Watch.
#HORIZON ZERO DAWN CAULDRON SIGMA FREE#
Power Cell location 1: Underground Bunker from the Prologue - You can get this one as soon as you have control of adult Aloy and free roam of the environment, after the Prologue-style mission, A Gift from the Past, with her as a child. Here's where to find them, but do note that there will be some minor spoilers below, in terms of location names at the very least, as all of these locations are visited at some point along the way during main story quests:
![horizon zero dawn cauldron sigma horizon zero dawn cauldron sigma](https://resource.supercheats.com/library/300w/2017/1491694702cauldron_sigma5c.jpg)
That being said, some are available very early on in the game - early enough, even, to get through the first of two puzzle locks that guard the Shield Weave armour after just a few hours of play - but that still won't get you the armour itself. There are five Power Cells in Horizon Zero Dawn, and you'll need to get a fair way through the main story in order to collect them all. Watch on YouTube Horizon Zero Dawn Power Cell locations