Nintendo Wii U GamePad WUP-002 Replacement Battery 3.7V 2450mAh

Nintendo Wii U GamePad — 3.7V Li-ion Replacement Battery (WUP-002 / ARR-002)

This is a 3.7V 2450mAh Li-ion replacement cell for the Nintendo Wii U GamePad (WUP-002). It fits the tablet-style controller used with the Wii U 8G console for both docked and off-TV play. Swap it in when the original cell no longer holds a charge or powers the GamePad through a full session.

• Wii U 8G GamePad compatibility: The WUP-002 and ARR-002 part numbers cover the same GamePad battery slot. Both connectors share the same 3.7V rail and pin-out, so either reference number confirms fitment on the Wii U 8G GamePad.
• Bench tested on actual hardware: We cycled this cell through the GamePad's charge IC and confirmed the BMS accepted the handshake without triggering a fault state. Charge current ramped correctly from pre-charge through CC and into CV taper.
• Fuel gauge calibration on first install: After fitting, run one complete wireless play session to automatic low-battery cutoff before recharging. The GamePad's fuel gauge IC sets its empty reference point against the first full discharge cycle — skipping this step leaves the percentage readout inaccurate for weeks.

Why the Wii U GamePad fuel gauge jumps or reads incorrectly after a cell swap

The GamePad uses a coulomb-counting fuel gauge IC that builds its discharge model from the cell it first mapped. When you install a new cell, that stored model no longer matches the new cell's chemistry curve, so the percentage display skips or jumps. The IC recalibrates by tracking actual voltage and current over a full discharge-to-charge cycle. Run the GamePad wirelessly — with screen on and no cable attached — until it shuts off automatically, then charge to 100% uninterrupted. After two to three cycles like this, the gauge reading stabilises.

GamePad losing wireless connection before the battery indicator shows low

This happens when combined wireless radio and rumble motor draw pulls the cell voltage below the BMS cutoff threshold before the fuel gauge catches up. The gauge reads the averaged voltage, but the instantaneous sag under peak load trips the protection circuit first. On a degraded or uncalibrated cell, that sag can occur at 20–30% displayed charge. After completing the first full calibration cycle described above, check whether the dropout moves to below 10% indicated — if it does, the cell is good and the gauge was simply uncalibrated. If dropout still occurs above 15% after three cycles, verify the battery connector is fully seated at 3.7V resting voltage with a multimeter.