A plasma battery is a form of Covenant power cell. Their exact purpose is unknown, though they probably hold energy needed for Covenant vehicles, machines, and equipment. However, they can be used as improvised explosive devices, due to their explosive reaction to weapons fire. It is possible they are a Covenant power source for plasma weapons which recharges them when they run out of battery power.
The Vantus-Pattern Eolipile is a prominent type of plasma battery distinguished by its triple-pronged shape. It was commonly fielded by the Covenant during the various campaigns of the Human-Covenant War.
In-game, plasma batteries are essentially the Covenant equivalent to the UNSC fusion core and the Forerunner power core. They require more shots than the fusion coil to explode. They also require a higher drop to detonate them on impact. It takes two explosions from a plasma battery to kill a fully shielded SPARTAN-II or Sangheili.
They appear in both campaign and multiplayer, and can be very useful to whomever sees the right moment to detonate it, such as near a pack of Grunts. These can also be bought when in Forge, costing a fair price. They can be placed anywhere on the map, even in mid-air. If in a last-ditch situation, you can kill enemies standing near either a plasma battery, a power core or a fusion coil by shooting at it. Any enemy killed using the explosion from a plasma battery will be listed as killed by you using an "Unknown" weapon. It appears to have energy shields as part of its structure, however, you don't need to deplete them to detonate it. There are stacks of them on the Halo 3 level, The Ark, and can be used to kill nearby enemies. Once one explodes, it causes a chain reaction of the explosions of nearby plasma batteries.
The Vantus-Pattern Eolipile as it appears in Halo 3.
A Vantus-Pattern plasma battery on Snowbound.
The Vantus-Pattern Eolipile in Halo: Reach.
Other Covenant batteries
Concept art depicting various Covenant plasma storage devices from Halo: Reach.
A remastered Covenant battery in Halo 2 Anniversary.
A Covenant battery in Halo 2.
A plasma battery next to a Covenant recharge station.
List of appearances
- Halo 2 (First appearance)
- Halo 3
- Halo 3: ODST
- Halo: Reach
- Halo 4
- Halo: Escalation
- Halo 2: Anniversary
- Halo 5: Guardians