Acer BAT-311 Liquid Z200 Replacement Battery 3.7V 1200mAh

Acer Liquid Z200 / Liquid M220 — 3.7V Li-ion Replacement Battery (BAT-311)

This is a 3.7V, 1200mAh Li-ion cell (4.44Wh) that replaces the original BAT-311 battery in the Acer Liquid Z200 and Liquid M220 series smartphones. It fits the standard Z200, Liquid M220, and Liquid M220 Dual SIM variants. When the original cell degrades, this swap restores full operating capacity to the device.

• Z200 and M220 platform compatibility: Both the Liquid Z200 and Liquid M220 share the same battery bay geometry, connector pinout, and BMS handshake protocol — the BAT-311 spec covers both lines without modification.
• Bench tested on actual hardware: We ran the cell through charge and discharge cycles on a Z200 unit. The BMS accepted the cell without fault flags, voltage held stable across display-on and modem-active load states, and charge termination fired correctly at 4.2V.
• Fuel gauge recalibration on first use: After fitting this cell, disable fast charging and run one full discharge-to-charge cycle before normal use. This lets the fuel gauge IC map its coulomb counter to the new cell's actual discharge curve before high-current charging begins on an uncalibrated reference.

Sudden shutdown at 20–30% on the Liquid Z200 after a cell swap

This happens because the fuel gauge IC is still referencing the old cell's voltage-to-capacity curve. The replacement cell has a steeper voltage cliff at the low end, so actual cell voltage drops below the modem's minimum rail before the OS reports 0%. The phone cuts power to protect the SoC even though the percentage shown looks safe. One full discharge cycle — running the phone to automatic shutdown, then charging uninterrupted to 100% — forces the coulomb counter to rebuild its table against the new cell.

Device not powering on after the replacement cell sat in storage

Li-ion cells self-discharge roughly 2–3% per month in storage. If the BAT-311 cell shipped or sat at the warehouse long enough, cell voltage may have dropped below 2.5V — the threshold where the BMS latches into lockout to prevent further discharge damage. The phone will show nothing on screen and will not respond to the power button. Connect the phone to a low-current charger (5V/500mA USB port, not a fast charger) and leave it for 20–30 minutes without pressing anything; the BMS trickle-charge circuit needs time to nudge the cell above 2.8V before it releases the lockout and allows normal charging to resume.