Lenovo A936 BL240 Replacement Battery 3.7V 3000mAh

Lenovo A936 — 3.7V Li-Polymer Replacement Battery (BL240)

This is a 3000mAh, 3.7V Li-Polymer cell that replaces the original BL240 battery in the Lenovo A936 smartphone. It restores the phone's ability to hold a charge after the original cell has degraded. Voltage and capacity match the OEM specification exactly.

• A936 platform fit: The A936 uses a fixed battery bay sized for the BL240 footprint — 97.36 × 69.09 × 3.96 mm. The connector alignment and BMS handshake protocol match the original charge IC, so the phone recognises the cell without any software workaround.
• Bench tested on actual hardware: We ran the cell through charge and discharge cycles on the A936 board. The BMS accepted the cell on first connect, charge termination triggered correctly at 4.2V, and the fuel gauge IC updated its state-of-charge reading without throwing a battery health warning.
• Fuel gauge recalibration on first use: After fitting this cell, disable fast charging and run one full discharge down to auto-shutdown, then charge uninterrupted to 100%. This gives the coulomb counter a clean reference cycle against the new cell's discharge curve before high-current charging begins.

Sudden shutdown at 20–30% on the A936 after a cell swap

This is a voltage cliff issue, not a capacity problem. When the modem fires during a call or the display jumps brightness, current draw spikes and the cell's instantaneous voltage drops below the BMS cutoff threshold — even though the fuel gauge still shows charge remaining. The fuel gauge IC on the A936 inherits calibration data from the old cell, so its percentage reading doesn't match the new cell's actual discharge curve. One full discharge-to-shutdown and uninterrupted recharge cycle resets the coulomb counter and eliminates most cliff shutdowns.

A936 not powering on after the replacement cell sat in storage

Li-Polymer cells self-discharge during storage. If the cell voltage has dropped below approximately 2.5V, the BMS enters a lockout state and blocks normal charging to prevent cell damage. The phone will show no response — no charge indicator, no boot. Connect the phone to a low-current charger (5V/500mA via USB) and leave it for 20–30 minutes; the charge IC uses a trickle pre-charge mode to bring the cell back above the BMS re-enable threshold of around 2.9V, after which normal charging resumes.