Cisco 7920 Replacement Battery 74-2901-01 3.7V 1960mAh

Cisco CP-7920 / CP-7920G — 3.7V Li-ion Replacement Battery (74-2901-01)

This 3.7V, 1960mAh Li-ion battery replaces the OEM pack in the Cisco 7920 series wireless IP handsets. It fits the CP-7920, CP-7920G, and CP-7920-FC-K9 models. The cell and connector match the original 74-2901-01 specification exactly.

• 7920 series compatibility: The CP-7920, CP-7920G, and CP-7920-FC-K9 all use the same 3.7V single-cell Li-ion pack with the same BMS handshake profile and JST-style connector. One replacement covers the whole platform.
• Bench tested on actual hardware: We ran this cell through charge cycles on a CP-7920G unit. The BMS accepted the pack without fault codes, balanced correctly at 4.2V, and held steady voltage under active VoIP call load.
• First charge after installation: Place the handset in the charging cradle immediately after installing this battery and leave it for a full uninterrupted charge cycle before using the phone. The Li-ion BMS on the 7920 calibrates its fuel gauge on the first full charge — skipping this step can cause the battery indicator to read inaccurately for several weeks.

Why the CP-7920 drops calls at the edge of Wi-Fi range after a battery swap

The 7920 transmits over 802.11b at 2.4GHz, and RF output draws a brief current spike each time the radio re-associates or compensates for a weak signal. If the replacement cell has elevated internal resistance — common in batteries that have sat in storage — voltage sags during that spike and the radio resets mid-call. A new Li-ion pack resolves this once it has completed two or three full charge cycles, which lowers internal resistance to the cell's rated level. If the issue persists after three cycles, check that the battery contacts on the handset are clean and making full contact.

Charging cradle shows no activity light after battery replacement

The 7920 cradle checks cell voltage before starting the charge circuit — if it reads below approximately 3.0V, it will not initiate charging and the indicator stays dark. This happens when a replacement battery has self-discharged during storage. Remove the handset, wait 30 seconds, and reseat it firmly so all three cradle contacts engage fully. If the light still does not activate, use a USB charger with a compatible Li-ion boost cable to bring the cell above 3.2V, then return it to the cradle.