Eufy 2C Pro Indoor Camera Compatible Battery 3.7V 5200mAh

Eufy 2C Pro Indoor Camera — 3.7V Li-ion Replacement Battery (SW18650 34M 2P)

This is a 3.7V, 5200mAh Li-ion replacement battery for the Eufy 2C Pro indoor camera and the broader 2C series, including the 2C Security Camera, 2C Wireless Door Camera, and 2K Wireless Door Camera. It uses the OEM part number SW18650 34M 2P and slots into the same battery bay as the original cell. When the factory battery can no longer hold a charge, this restores the camera's wireless, cord-free operation.

• 2C series compatibility: The 2C Pro, 2C Security, and 2C Wireless Door Camera all share the same 3.7V battery architecture and connector layout. The BMS handshake is tied to voltage threshold rather than a proprietary authentication chip, so this cell is recognised by the camera firmware without modification.
• Bench tested on actual hardware: We ran this battery through charge and discharge cycles on the 2C platform and confirmed the BMS held stable voltage under the combined current draw of the IR LEDs and the motion-event processor spike. No premature cutoff was triggered under normal operating conditions.
• App registration after install: After fitting this battery, power cycle the camera once through the Eufy Security app. The firmware must register the new cell before motion recording events log correctly to cloud storage — skipping this step can cause missed clips in the activity log.

Camera going offline in the Eufy app after battery swap

Swapping the battery clears the camera's active session token, which the Eufy app uses to maintain the live device link. The camera comes back online at the hardware level, but the app does not automatically re-establish the session. Go into the Eufy Security app, navigate to the device settings for the affected camera, and force a reconnect or remove and re-add the device. Once the session is re-registered, live view and push alerts return to normal.

App displaying 0% or incorrect battery percentage after install

The 2C series uses a voltage-threshold indicator rather than a fuel gauge IC, so the percentage reading is inferred from resting cell voltage. A freshly installed battery may not sit at the voltage point the firmware expects for a full charge, causing the app to report 0% or an anomalous figure. Run one full charge cycle through the camera's own charging port until the indicator confirms 100%, then discharge under normal motion-detection use. After one complete cycle, the voltage-to-percentage mapping recalibrates and readings stabilise.