Cisco WebEx 860 Replacement Battery 3.85V 3000mAh Li-ion

Cisco WebEx 860 Series — 3.85V Li-ion Replacement Battery (BLI0000100)

This 3.85V, 3000mAh Li-ion cell replaces the original battery in the Cisco WebEx 860 and WebEx 860S video conferencing handsets. It also covers the CP-860-BUN-K9 and CP-860S bundle configurations using OEM part numbers BLI0000100, CP-860-BAT, and 74-127733-01. Capacity figure is taken directly from the product specification — 11.55Wh.

• WebEx 860 series fit: The 860 and 860S share the same battery bay dimensions, voltage rail, and BMS handshake protocol. All listed models accept the same 3.85V cell with identical connector pinout, so one part number covers the full lineup.
• Bench tested on actual hardware: We cycled this cell through the WebEx 860 charge IC and confirmed the BMS handshake completes correctly. Charge termination triggered at the expected cutoff voltage with no false-full flags on the first cycle.
• First-cycle fuel gauge reset: On first use after installation, disable fast charging and run one full discharge-to-charge cycle. The fuel gauge IC on the 860 calibrates its coulomb counter against the new cell's discharge curve — skipping this step leaves the percentage readout offset by as much as 15% until the IC self-corrects.

Sudden shutdown at 20–30% on the WebEx 860 after a cell swap

A fresh cell has a slightly different discharge curve than the aged cell the fuel gauge IC was trained on. At high-draw moments — active video call, screen at full brightness, Wi-Fi transmitting — the cell voltage dips sharply below 3.5V even though the percentage display still reads 20–30%. The BMS reads that voltage drop as a low-cell event and cuts output immediately. Running one full discharge cycle lets the coulomb counter remap the curve and pushes the real cutoff point back to where it belongs, around 3.3–3.4V under load.

USB-PD fast charge not activating on the first charge after replacement

After installing a new cell, the charge IC on the WebEx 860 may default to standard 5V/0.9A trickle mode and decline to negotiate fast charge on the first cycle. This happens because the BMS presents a higher impedance on a new, unformatted cell — the charge IC interprets this as an unsafe charge state and refuses to step up current. Plug into the standard Cisco charger, allow the first full cycle to complete at base rate, and fast charge will re-enable automatically once the IC accepts the new cell's impedance profile. Check that the charging indicator shows the fast-charge icon on the second cycle.