Microsoft Xbox X360 Wireless Controller AX3GBP Replacement Battery 2.4V 1200mAh

Microsoft Xbox X360 — 2.4V Ni-MH Replacement Battery (AX3GBP)

This is a 2.4V, 1200mAh Ni-MH rechargeable battery pack for the Microsoft Xbox 360 wireless controller. It replaces part number AX3GBP and restores wireless play without disposable AA batteries. Capacity is 2.88Wh — matched to the original cell specification.

• Xbox 360 wireless controller fit: The Xbox 360 controller uses a dedicated NiMH pack bay with a specific connector and contact orientation. This cell matches that physical format and the 2.4V rail the controller's power circuit expects. Swapping chemistry or voltage here causes charge failures or no-power conditions.
• Bench tested on actual hardware: We ran this pack in an Xbox 360 controller through full charge-discharge cycles on the bench. The controller's charge IC accepted the cell without fault codes, and the BMS completed charge termination correctly at capacity without false cutoff.
• First-cycle calibration tip: On first use after installing, run one complete wireless play session to full automatic controller cutoff before recharging. The Xbox 360 fuel gauge calibrates its empty reference point against the first full discharge cycle — skipping this produces inaccurate battery indicator readings for subsequent sessions.

Why the Xbox 360 controller disconnects before the battery indicator hits empty

The Xbox 360 controller pulls current from both the wireless radio and the rumble motors simultaneously during heavy play. Under that combined load, voltage sags briefly below the controller's minimum operating threshold even when the cell still holds remaining charge. The firmware reads the voltage drop as a fault and drops the wireless link before the fuel gauge catches up. This is a cell-voltage sag issue, not a capacity problem — and it reduces as the new pack conditions over three to five charge cycles.

Battery indicator jumping around or reading full after a fresh cell install

The Xbox 360 controller's fuel gauge IC tracks charge state against a stored discharge curve from the previous cell. A brand-new cell has a different curve, so the gauge reads incorrectly until it recalibrates. Run the controller on wireless to automatic cutoff, then charge fully without interruption. After one complete cycle, the gauge IC sets a new empty reference point and the indicator stabilises. If it still jumps after two cycles, confirm the battery contacts are seated flat — a loose contact creates voltage noise the gauge misreads as a state-of-charge change.