Garmin Vivoactive 3 Replacement Battery 3.7V 160mAh

Garmin Vivoactive 3 / Vivoactive 3 Music — 3.7V Li-Polymer Replacement Battery (361-00108-00)

This is a 3.7V, 160mAh lithium-polymer cell replacing OEM part 361-00108-00 (also cross-references 361-00108-01). It fits the Garmin Vivoactive 3 and Vivoactive 3 Music smartwatches. Dimensions are 22.50 × 20.50 × 4.50mm — measure your original cell before ordering if your unit has been previously serviced.

• Vivoactive 3 and Vivoactive 3 Music compatibility: Both models share the same battery bay geometry, connector pinout, and BMS handshake protocol. The Music variant draws slightly more current during Bluetooth audio streaming, but the cell specification is identical across both platforms.
• Bench tested on actual hardware: We ran this cell through charge acceptance, BMS communication, and GPS lock sequences on a Vivoactive 3 unit. The BMS recognised the cell without fault codes, and the fuel gauge IC updated state-of-charge correctly after one full charge cycle.
• Post-swap charging requirement: After fitting this cell, place the watch on its magnetic charger immediately and charge fully to 100% before first use. The fuel gauge IC on the Vivoactive 3 loses its charge reference during cell removal — it cannot calibrate accurately without a complete charge cycle starting from near-zero.

Why the Vivoactive 3 reports incorrect battery percentage after a cell swap

The Vivoactive 3 uses a coulomb-counting fuel gauge IC that tracks charge relative to a stored baseline. When the original cell is removed, that baseline is lost. The IC then estimates state-of-charge from the new cell's open-circuit voltage, which is rarely precise at rest. This causes the watch to report inflated or deflated percentages — sometimes jumping from 80% to 20% mid-use — until the IC re-establishes its reference through a full 0-to-100% charge cycle.

Magnetic charge contacts not connecting after reassembly

If the watch fails to register on its magnetic charger after battery replacement, the most common cause is the rear case shifting slightly during reassembly, misaligning the charging contacts. Remove the rear cover, reseat it firmly and evenly, then reattach. Check that no adhesive or debris is sitting on the contact pads — clean with isopropyl alcohol if needed. The charger LED should illuminate within 10 seconds of correct contact; if it does not, recheck alignment before assuming a cell fault.