Yealink CP900 Replacement Battery 3.85V 2200mAh

Yealink CP900 — 3.85V Li-Polymer Replacement Battery (YLPP425268C2450WLS)

This 3.85V, 2200mAh Li-Polymer battery replaces the original YLPP425268C2450WLS pack in the Yealink CP900 portable conference speakerphone. It restores wireless audio conferencing functionality when the original cell has degraded or stopped holding charge. Dimensions are 68.50 × 49.40 × 4.50mm — verify against your existing pack before installing.

• CP900 platform fit: The CP900 runs its Bluetooth audio stack and speaker amplifier off a single Li-Polymer cell at 3.85V nominal. This replacement matches that voltage rail and the BMS communication protocol the unit expects on power-up. No firmware changes or adapter hardware required.
• Bench tested on actual hardware: We cycled this pack through the CP900's charge and discharge sequence and monitored BMS handshake at startup. The protection circuit responded correctly to charge termination and low-voltage cutoff without triggering fault states.
• First-session calibration tip: After installing, run a full charge cycle before your first meeting. The CP900 maps battery state against voltage thresholds during normal operation. A freshly swapped pack that hasn't completed one full cycle will often report inaccurate charge warnings for that first session.

Voltage sag under combined wireless and audio draw on the CP900

The CP900 runs Bluetooth transmission and speaker amplification simultaneously during a call. That combined draw pulls more current than standby or charge mode, and an aged or deeply discharged cell will sag below the BMS low-voltage threshold mid-session. When that happens, the unit shuts down or drops the wireless connection even though the battery indicator hadn't reached zero. A fresh cell at full nominal voltage — 3.85V — handles this load without triggering the cutoff.

Battery indicator stuck at incorrect level after a pack swap

The CP900 doesn't use a fuel-gauge IC that tracks coulombs — it estimates charge from voltage curves it learns during operation. A replacement pack pulled straight from storage sits at a resting voltage that may not match any calibrated point in the unit's memory. The indicator then displays a level that doesn't reflect actual capacity. One complete charge-to-full, then normal use until the unit signals low, resets the reference points and brings the indicator back into accuracy.