Garmin Vivoactive 360-00033-00 Compatible Battery 3.7V 150mAh

Garmin Vivoactive — 3.7V Li-Polymer Replacement Battery (360-00033-00)

This is a 3.7V, 150mAh Li-Polymer cell for the Garmin Vivoactive smartwatch. It replaces the original 360-00033-00 battery when charge capacity has degraded to the point where the watch no longer lasts through a full day. The cell measures 32.40 × 20.14 × 3.56mm and fits the Vivoactive chassis without modification.

• Vivoactive platform fit: The Vivoactive uses a fixed-footprint Li-Polymer cell with a dedicated connector and flex cable routed beneath the display assembly. This replacement matches that connector pinout and physical envelope, so the BMS handshake between the cell and the watch's fuel gauge IC completes correctly on power-up.
• Bench tested on actual hardware: We ran this cell on a Vivoactive unit with GPS active and continuous heart rate monitoring enabled. The BMS accepted the cell without fault codes, and the fuel gauge IC initialised and began tracking state-of-charge from the first charge cycle.
• Post-swap charge requirement: After fitting this cell, place the watch on its magnetic charger immediately and charge to 100% before first use. The fuel gauge IC on the Vivoactive cannot calibrate its state-of-charge reference without a full charge cycle from near-zero following a cell swap — skipping this step causes the display to show incorrect percentages.

Why the Vivoactive reports 0% immediately after a battery swap

The Vivoactive uses a coulomb-counting fuel gauge IC to track battery percentage. When the original cell is disconnected, that IC loses its reference point entirely. A new cell connected at partial charge gives the IC no baseline to work from, so it defaults to 0% or refuses to power on. Placing the watch on charge immediately after the swap and running a full charge to 100% re-establishes the IC's reference. Once that first full cycle completes, percentage readings stabilise.

Watch not pairing with phone after battery replacement

Removing the battery clears active BLE session data on the Vivoactive. The watch and phone no longer share a bonding key, so the phone's Garmin Connect app cannot find the device even though Bluetooth is enabled on both. The fix is to remove the Vivoactive from the paired devices list on your phone, then re-pair it fresh through the Garmin Connect app. Go to the app's device menu, select "Add Device," and follow the on-screen steps — the watch must be powered on and showing the pairing screen.