Louis Vuitton Tambour Horizon 1 Replacement Battery 3.8V 300mAh

Louis Vuitton Tambour Horizon 1 — 3.8V Li-Polymer Replacement Battery (APP00207)

This is a 3.8V, 300mAh lithium-polymer cell for the Louis Vuitton Tambour Horizon 1 smartwatch. It replaces part number APP00207. Fit this battery when the original cell no longer holds charge or the watch shuts down unexpectedly under normal use.

• Tambour Horizon 1 platform: The Horizon 1 uses a compact Li-Polymer format with a specific connector orientation and BMS handshake tied to the watch's fuel gauge IC. Only cells matched to the APP00207 footprint will seat correctly and communicate charge state to the display.
• Bench tested on actual hardware: We ran this cell through charge and discharge cycles on the Tambour Horizon 1 platform and confirmed the BMS accepted the cell without fault flags, and the fuel gauge reported accurate state-of-charge across the full voltage window from 3.0V to 4.2V.
• Post-swap charge protocol: After fitting this cell, place the watch on its magnetic charger immediately and run it to 100% before first use. The Tambour Horizon 1 fuel gauge IC loses its reference point when the cell is removed — a full charge cycle from near-zero is what resets the calibration, not powering the watch on first.

Always-on display and continuous heart rate monitoring drawing down the APP00207 cell

The Tambour Horizon 1 display is a significant current draw on its own. Add continuous heart rate monitoring and a BLE connection and the combined load on a 300mAh cell is substantial. If the watch is set to always-on display mode with heart rate polling active, expect noticeably faster drain than the factory spec — that is not a cell fault. Disabling always-on display is the single highest-impact change you can make to extend charge intervals on this platform.

Watch not pairing with phone after battery replacement

Removing the battery cuts power to the BLE controller entirely, which drops the active pairing session stored in volatile memory. The watch and phone no longer recognise each other after power is restored. This is not a defective cell — it is a session loss from hard power removal. Open your phone's Bluetooth settings, forget the Tambour Horizon device, then re-pair it fresh through the Louis Vuitton companion app.