About this replacement
Doogee X11 — 3.8V Li-ion Replacement Battery (BAT1850122250)
This is a 3.8V, 1900mAh Li-ion cell built to replace the original BAT1850122250 battery in the Doogee X11 smartphone. It restores power to the device when the original cell has degraded or failed. Voltage and capacity match the OEM specification exactly.
- X11 platform fit: The Doogee X11 uses a fixed 3.8V single-cell Li-ion configuration with a BMS that checks cell impedance on boot. This replacement cell matches that impedance profile, so the BMS handshake completes without a boot loop or low-battery rejection on first power-up.
- Bench tested on actual hardware: We cycled this cell through charge and discharge on the X11 platform. The BMS accepted the cell on first connection, charge termination triggered correctly at 4.35V, and no overcurrent flags appeared during a full discharge sequence.
- Fuel gauge recalibration on first cycle: On first use after installation, disable fast charging and run one complete discharge-to-charge cycle before enabling any accelerated charging mode. This gives the fuel gauge IC time to map the new cell's discharge curve before high-current charging pushes load into an uncalibrated cell.
Sudden shutdown at 20–30% on the Doogee X11 after a cell swap
This happens because the fuel gauge IC is still using the discharge curve from the old, degraded cell. When the new cell hits a voltage point the IC interprets as critically low — typically around 3.5V under modem or screen load — it triggers an emergency shutdown even though capacity remains. The fix is one full uninterrupted discharge from 100% down to automatic shutdown, followed by a full charge without interruption. After that cycle, the coulomb counter resets against the actual new cell curve and percentage reporting stabilises.
Doogee X11 not powering on after the replacement cell sat in storage
Li-ion cells self-discharge during storage. If the voltage drops below approximately 2.5V per cell, the BMS enters lockout mode to prevent damage and the phone will not respond to a standard boot press. Connect the phone to a wall charger — not a PC USB port — and leave it for 15–20 minutes without pressing anything. The charge IC will trickle current into the cell until it clears the BMS lockout threshold, after which normal charging resumes. If the charging indicator does not appear within 30 minutes, check that the charger output is at least 5V 1A.