For the object referred to as a "Big Energy Ball" in the Super Metroid manual, see Energy Capsule.
Found in Metroid II: Return of Samus and essentially the precursor to the Energy Charges from subsequent games, the Big Energy Ball replenishes Samus' entire energy store upon contact. However, unlike the aforementioned Energy Charges, these large shimmering energy balls are usually found in remote locations within the regular playable field, hidden in every area except Phase 5 and Phase 8. In Phase 1, the Star Ship contains a Missile Battery and a Big Energy Ball.
Currently, Metroid II: Return of Samus is the only game to feature this item. Its remake, Metroid: Samus Returns, replaces them with Energy Recharge Stations, although the Big Aeion Orbs seen throughout SR388 are similar in appearance and function.
Metroid II manual
"This will refill all energy tanks to maximum."
- The Big Energy Ball does not have any artwork in the manual.