Binding of Isaac: Rebirth Wiki

(in Repentance)

4.5 Volt is a passive item added in The Binding of Isaac: Repentance.

Effects[ | ]

  • Causes Isaac's active item to charge when Isaac deals damage to enemies, rather than when he clears rooms.
    • Damage dealt by charmed/friendly enemies, active items, orbitals and familiars (including blue flies and spiders) works as well.
  • Charges are gained at a rate equal the following formula: (40 + (20 x stage)). For example:
    • In BasementBasement I / DownpourDownpour I, it takes 60 damage to gain 1 charge.
    • In CavesCaves II / MinesMines II, it takes 120 damage.
    • In WombWomb I / CorpseCorpse I, it takes 180 damage.
    • In SheolSheol / CathedralCathedral, it takes 240 damage.
    • In HomeHome, it takes 300 damage.
    • Ascent floors use the values of their regular floors, meaning the amount of damage 4.5 Volt needs to gain charges steadily decreases during the Ascent sequence until reaching Home.
  • Multiple charges cannot be gained at once.
  • Overkill damage does not count towards a charge.

Notes[ | ]

  • Tainted characters with active items in their pill/card slot will not have those items charged by 4.5 Volt if their active item isn't already fully charged.
  • Character Lilith iconLilith can be particularly strong with 4.5 Volt during long fights such as Boss Delirium ingameDelirium and Boss Hush ingameHush, especially if she still has the Collectible Box of Friends iconBox of Friends, as the damage she deals will allow her to repeatedly duplicate her familiars, dealing many times her typical damage during a single fight.
  • Character Bethany iconBethany will benefit from 4.5 Volt's effect for regular item charges while retaining her ability to use Soul HeartSoul Hearts as item charges. This applies to Character Tainted Bethany iconTainted Bethany with her Red HeartRed Heart charges as well.
  • Character Tainted Jacob iconTainted Jacob will gain charges from 4.5 Volt when Dark Esau damages enemies.
  • While the two versions of Character Tainted Lazarus iconTainted Lazarus normally charge both their active items at the same time, 4.5 Volt will only charge when the state that holds it deals damage, and will prevent it from being charged when the other clears a room. This makes 4.5 Volt much worse while playing Character Tainted Lazarus iconTainted Lazarus.

Synergies[ | ]

  • Collectible Book of Shadows iconBook of Shadows: With sufficient damage, the Book of Shadows can be kept active indefinitely.
    • If combined with Collectible 9 Volt icon9 Volt, it becomes even easier to achieve invincibility.
  • Door StopDoor Stop / Collectible Mercurius iconMercurius / any means of room resetting (infinite bombs): Provides infinite charges by clearing some enemies then leaving the room, and repeating.
  • Collectible Jumper Cables iconJumper Cables: Increases the rate of charge by appending its 15-kills-per-charge quality on top of 4.5 Volt's damage-based charge.
  • Old CapacitorOld Capacitor: Since the 4.5 Volt also makes it so that active items don't charge when clearing rooms, this trinket can be picked up with no downside.
  • Collectible Unicorn Stump iconUnicorn Stump + Collectible Sacrificial Dagger iconSacrificial Dagger: In most boss fights, charges are regenerated faster than invincibility wears off.
  • Collectible White Pony iconWhite Pony: Since the beam trail from the charge attack deals so much damage, if used on a boss with a high amount of health, 4.5 Volt will often completely recharge the item after each use allowing for repeated usage while the boss is still alive.

Interactions[ | ]

  • Does not charge items which gain charge over time by default. (e.g. Collectible Sharp Straw iconSharp Straw, Collectible The Candle iconThe Candle, Collectible Butter Bean iconButter Bean etc.)
    • Items converted to charge-over-time by Collectible 9 Volt icon9 Volt are not affected and may gain charge in both ways.
  • Collectible Alabaster Box iconAlabaster Box: No effect. It still must be charged with Soul Hearts.
  • Dim BulbDim Bulb: Does not deactivate until the first charge bar is completely filled. A partial charge of the first bar will retain Dim Bulb's bonus.
  • Collectible Schoolbag iconSchoolbag: The item in the second slot gets charged when the first one is full. Overcharges on the first item also jump to the second one.

In-game footage[ | ]

Trivia[ | ]

  • The game files name 4.5 Volt's icon as "assaultbattery", which may imply "Assault and Battery" was its original name.
    • Assault and battery is the combination of two violent crimes in common law: assault (the threat of violence) and battery (physical violence).

Bugs[ | ]

Bug Bug! With Collectible 9 Volt icon9 Volt and Collectible The Battery iconThe Battery, the gradual charge of 4.5 Volt is separate from 9 Volt's charge on one-charge items rather than being additive.