Batteries

This article is about the pickup. For the item, see The Battery. For other uses, see Battery (Disambiguation).

Batteries add charges to Isaac's active item when picked up.

Battery	ID	Charges	Notes	Unlock Method	Probability
Lil' Battery	5.90.1	Full 6	If Isaac has The Battery with no overcharge, only the main charge bar is filled. If the main bar is full, the overcharge is filled.		32.72%
Micro Battery	5.90.2	2			65.45%
Mega Battery	5.90.3	Full (x2)	Overcharges Isaac's active item up to two full charges as if The Battery was held. If Isaac has multiple active items, it will charge all of them twice.		1.00%
Golden Battery	5.90.4	6	Deals a full heart of damage when picked up. Another golden battery will spawn in a random room, but it is not shown on the map until discovered.	Defeat Mega Satan as Tainted Forgotten	0.83%

Notes

Mega Blast only gains 3 charges per battery.
Batteries charge only the current active item, if holding multiple.
- If Isaac has an active item in the consumable slot, batteries prefer to charge the active item slot first.
Holy Mantle and similar effects will block the damage from the Golden Battery, allowing for infinite usage of active items on that floor.
Golden Batteries can re-appear in undiscovered rooms, including the Secret Room.
- It can re-appear in every previously visited rooms that are displayed on the map, even in the mirrored area where Knife Piece 1 is located, in the abandoned area where Knife Piece 2 is located, or in the Death Certificate path
- It can't appear in any room that is not displayed on the map at anytime, like Crawl Space, Black Market, Downpour entrance, Mines entrance, I AM ERROR room.
The probabilities in the table refer to the kind of battery that is generated by the game when a battery pickup is spawned with a sub-type of 0 (i.e. a random battery).
Items / pickups with the D20 effect can reroll batteries, but can't reroll other pickups into batteries.

Bug!	If a Golden Battery appears in the Abandoned Area before the Mother's Shadow chase, it will despawn for the floor, as the room configuration is changed when the chase begins.