Binding of Isaac: Rebirth Wiki

9 Volt is a passive item.


  • Fully charges the current activated item upon 9 Volt's first pickup.
  • If the current activated item has a recharge time of more than 1 bar, then it will grant 1 bar of charge whenever the item is activated.
  • If the current activated item has a recharge time of 1 bar, then it will change the item to have a timed recharge of 15 seconds. The recharging of the item only triggers so long as there are enemies present in the room in any fashion. Empty rooms do not cause recharging to start. Note: this is extremely powerful for some single-charge items like Keeper’s starting item, Wooden Nickel. You can make a circle around the room with one fly and farm infinite coins this way, making for an easy devil and store run.
    • An enemy spawned in a cleared room will also cause recharging to start.
  • If the current activated item already has a timed recharge, 9 Volt makes it start at half charge when used, effectively halving the time to recharge and allowing quicker reuse.



  • 2-bar items: Fills the entire gauge in a single room, effectively granting the opportunity for the item to be used every room.
  • Added in Afterbirth † 3-bar items: Quadruple rooms and L-shaped rooms give 2 bars after clearing them, allowing one free use of the item in those rooms if the gauge is full upon entering them. It can also be used at the beginning of a Boss Challenge Room to get the full charges back after beating both bosses.
  • Added in Afterbirth † 4-bar items: In a Challenge Room, if the item is used during the first wave, it will get all its charges back at the end.
    • Added in Afterbirth † AAA Battery AAA Battery + 4-bar items: Same as the 3-bar item synergy without AAA Battery.
  • Added in RepentanceAdded in Afterbirth †Telekinesis Telekinesis the active item can be reactived the moment the previous charge stops, making it always active


  • 9 Volt 9 Volt: No further decrease in charges.
  • Added in RepentanceAlabaster Box Alabaster Box: No effect.
  • Added in Afterbirth †Dim Bulb Dim Bulb: Prevents Dim Bulb from working, as minimum charge becomes 1 instead of 0.
  • Added in RepentanceEraser Eraser: No effect.
  • Added in RepentanceEverything Jar Everything Jar / Added in RepentanceLarynx Larynx: The first bar gains an automatic recharge, but the further bars will not be affected.
  • Removed in RepentanceSharp Plug Sharp Plug: Renders the Sharp Plug unusable on 2+ charge items. Sharp Plug can only be used if the item is at 0 charges, but 9 Volt instantly gives +1 charge to the item upon activation.
    • Added in Repentance Lowers the cost of using Sharp Plug by half a heart on 2+ charge items.

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