BenQ P50 Replacement Battery 3.7V 1800mAh Li-Polymer

BenQ P50 — 3.7V Li-Polymer Replacement Battery (23.20115.102)

This is a 3.7V 1800mAh Li-Polymer battery for the BenQ P50 smartphone. It replaces OEM part number 23.20115.102 when the original cell can no longer hold a usable charge. Dimensions are 53.11 × 34.07 × 5.31mm — verify fit before installation.

• BenQ P50 compatibility: The P50 uses a single-cell Li-Polymer pack at 3.7V nominal with a fixed connector and BMS handshake tied to part number 23.20115.102. This replacement matches that voltage rail and connector — the charge IC communicates with the BMS the same way it did with the factory cell.
• Bench tested on actual hardware: We cycled this cell through full charge and discharge on a P50 unit, confirming BMS handshake, charge cutoff at 4.2V, and stable voltage delivery under screen and modem load without triggering low-voltage protection prematurely.
• Fuel gauge recalibration on first use: After installation, disable fast charging and run one complete discharge-to-charge cycle at standard rate. The P50's fuel gauge IC was calibrated to the original cell's discharge curve — giving it one full cycle on the new cell before fast charge resumes lets it map the new curve accurately.

Sudden shutdown at 20–30% on the BenQ P50 after a cell swap

This happens because the fuel gauge IC still references the discharge curve of the old, degraded cell. When the new cell hits a voltage point the IC associates with low charge, it signals shutdown — even though actual capacity remains. The P50's modem and display draw brief high-current spikes that accelerate this voltage cliff if the gauge is miscalibrated. One full discharge down to automatic shutoff, followed by a complete charge to 100%, forces the coulomb counter to reset against the new cell's actual curve.

BenQ P50 not powering on after the replacement battery sat in storage

Li-Polymer cells self-discharge in storage and can drop below 2.5V per cell, which triggers a BMS lockout designed to prevent damage from over-discharge. The P50 will show no response — no boot, no charge indicator — when the BMS is in this locked state. Connect the phone to a wall charger rather than USB for at least 20–30 minutes without pressing any buttons; the charge IC will trickle current into the cell until it recovers above the BMS re-enable threshold of approximately 2.9V. Once the charge LED activates, the BMS has re-initialised and normal charging resumes.