Wiko Birdy Replacement Battery 3.8V 2100mAh Li-ion

Wiko Birdy Series — 3.8V Li-ion Replacement Battery (Birdy)

This 3.8V, 2100mAh Li-ion cell replaces the original battery in the Wiko Birdy, Birdy 4G, and 9261 smartphones. It matches the OEM voltage rail and physical footprint — 64.31 × 55.88 × 4.80mm — so the back cover seats correctly without modification. Capacity is rated at 7.98Wh.

• Birdy, Birdy 4G, and 9261 compatibility: All three models share the same battery bay dimensions, 3.8V nominal voltage, and connector pinout. The BMS handshake is identical across the series, so one cell covers all three variants without firmware conflict.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on the Birdy platform. The BMS accepted the charge profile without triggering cutoff, and voltage held steady at load across the modem and display draw we applied.
• First-cycle calibration tip: On first use after installation, disable fast charging and run one complete discharge-charge cycle. This lets the fuel gauge IC map its coulomb counter against the new cell's actual discharge curve before high-current charging begins on an uncalibrated reference.

Sudden shutdown at 20–30% on the Wiko Birdy after a cell swap

The Birdy's fuel gauge IC stores a discharge curve calibrated to the original cell. A new cell has different internal impedance, so the IC's voltage-to-percentage mapping is off from the moment you install it. When the modem fires up a data burst or the screen ramps brightness, the new cell's voltage dips sharply — and the IC reads that dip as a hard cutoff, killing the phone before the gauge hits zero. One full discharge-charge cycle with fast charging off corrects the reference map and eliminates the false cutoff.

Phone won't power on after the replacement battery sat in storage

Li-ion cells self-discharge in storage, and if the replacement cell drops below roughly 2.5V per cell, the BMS enters lockout to prevent damage — the phone shows nothing when you press the power button. Plug into a wall charger, not a USB port, and leave it for 20–30 minutes without attempting to power on. Most BMS circuits will accept a trickle-charge recovery at that point and unlock once voltage climbs back above the threshold.