Amazfit Stratos Replacement Battery 3.8V 290mAh PL332728V

Amazfit Stratos / Stratos 2 (A1609, A1619) — 3.8V Li-Polymer Replacement Battery (PL332728V)

This is a 3.8V, 290mAh Li-Polymer cell built to the PL332728V specification. It fits the Amazfit Stratos and Stratos 2 smartwatches (models A1609 and A1619). The cell powers the display, heart rate sensor, GPS module, and Bluetooth stack.

• Stratos and Stratos 2 platform fit: Both watch generations share the same chassis dimensions and battery bay. The PL332728V footprint — 28.00 × 27.30 × 3.40mm — matches the original cell exactly, so the flex connector seats without force and the BMS handshake completes normally on first boot.
• Bench tested on actual hardware: We cycled this cell through the Stratos charge controller and confirmed the BMS accepted the cell, reported accurate state-of-charge over several cycles, and did not trigger overcurrent cutoff during GPS lock — the highest sustained draw state on this platform.
• Fuel gauge calibration after cell swap: Place the watch on its magnetic charger immediately after fitting this cell and charge it to 100% without interruption. The fuel gauge IC on the Stratos platform loses its reference point when the original cell is removed. Without a full charge cycle from near-zero, the gauge cannot re-anchor and will report wildly inaccurate percentages.

Why GPS lock drains the Stratos cell faster than standby

The Stratos uses a dedicated GPS chipset that draws significantly more current than the heart rate sensor or Bluetooth stack alone. During active GPS tracking, the SoC, GPS module, and HR sensor run concurrently — the combined load hits the cell hard at a sustained rate. A 290mAh cell at that draw level will deplete faster than casual use suggests. This is normal behaviour on this platform, not a cell defect. If drain seems excessive outside of GPS sessions, check whether always-on display or continuous HR monitoring is enabled in the Amazfit app.

Watch not pairing with the Amazfit app after battery replacement

Removing the battery kills the Bluetooth session entirely — the watch loses its pairing record at the hardware level. The phone retains the old pairing entry, but the watch boots with no matching session, so the handshake fails silently. Go into your phone's Bluetooth settings, forget the Stratos device, then open the Amazfit app and pair from scratch. The watch must show the pairing screen — hold the side button for three seconds after first boot to reach it if it does not appear automatically.