How to Find and Use the Fuel Array in Risk of Rain 2
Learn how to obtain the volatile Fuel Array, its unique explosion mechanics, and how to use it to unlock the survivor REX in Risk of Rain 2.
Published: Risk of Rain 2 Wiki Editorial Team
Table of Contents
Obtaining the Fuel Array
The Fuel Array is a unique, world-interactive equipment item in Risk of Rain 2 that serves a specific purpose: unlocking the survivor REX. You can only acquire it during the very first stage of a run by walking to the back of the Escape Pod you spawned in. Simply interact with the hatch to open it and collect the item.
Because this item is tied to the starting Escape Pod, you cannot obtain it in a single-player run if you choose characters like MUL-T, Acrid, or the Void Fiend, as they do not start their journey in a pod. In multiplayer games, if a player drops the item, others can pick it up.
Understanding the Volatile Mechanic
The Fuel Array is labeled as "EXTREMELY unstable," and this is not just flavor text. It functions differently than any other equipment in the game. You cannot manually activate it; instead, it has a passive, mandatory trigger: if your health drops below 50% of your maximum capacity, the Fuel Array will automatically detonate.
When it explodes, it deals massive, fixed damage (300% of your max health) to anything in a 30-meter radius, including you. Community reports confirm that this explosion is often fatal, even if you have temporary shields or barriers active, because the game calculates the percentage based on your total health pool. Triggering a Blood Shrine while carrying the Fuel Array is a guaranteed way to end your run prematurely.
Tip
Survival Strategies: To increase your chances of reaching the Abyssal Depths, prioritize items like Rose Bucklers to boost armor while sprinting, or rely on mobility to avoid high-damage hits from enemies like Stone Golems. Invincibility frames from skills (such as the Mercenary's Blinding Assault) or specific items like Safer Spaces can help negate the explosion damage if timed perfectly.
Unlocking REX
The primary reason to endure the instability of the Fuel Array is to complete the "Power Plant" achievement. You must successfully carry the item through your run to the fourth stage, the Abyssal Depths.
Once you reach the Abyssal Depths, look for the broken robot resting on one of the higher platforms. You can typically reach these platforms using the large chains or jump pads scattered throughout the map. When you stand next to the robot, interact with it while the Fuel Array is equipped. This will repair the robot and grant you the Power Plant achievement, permanently unlocking REX as a playable survivor. Note that the Fuel Array is consumed and removed from your inventory immediately upon completion.
Advanced Tips and Common Pitfalls
Players often find the journey to Stage 4 difficult due to the "half-health" penalty. Here are some key considerations based on community experience:
One-Shot Protection: The explosion does not bypass standard one-shot protection. If you have enough health recovery to trigger this protection, you might theoretically survive, though it is highly unreliable.
Engineer Utility: The Engineer can use the Fuel Array effectively in some scenarios, as his stationary turrets may also carry the item. While this causes the turrets to explode when damaged, it can deal significant damage to surrounding enemies.
Multiplayer Caution: If you are playing with friends, remember that only the person who interacts with the robot while carrying the Fuel Array will unlock REX. You can, however, have multiple players repair the robot in the same session if each player finds their own Fuel Array.
Equipment Swapping: Be careful not to swap the Fuel Array for another item unless you are ready to part with your progress. If you accidentally give it to an Equipment Drone, it becomes inaccessible and will be lost when the drone is destroyed.
