About this replacement
Huawei GT2 46mm / Magic Watch 2 46mm — 3.82V Li-Polymer Replacement Battery (HB532729ECW)
This 3.82V, 450mAh Li-Polymer cell replaces the original HB532729ECW battery in the Huawei Watch GT2 46mm, Magic Watch 2 46mm (MNS-B19), and GT2 Pro. It restores power to the display, heart rate sensor, GPS module, and Bluetooth stack. Dimensions are 25.75 × 25.42 × 4.85mm — confirm yours matches before opening the case.
- GT2 46mm, Magic Watch 2 46mm, and GT2 Pro compatibility: These models share the same cell footprint, connector orientation, and BMS handshake protocol. The HB532729ECW part number covers all three variants — the voltage rail and fuel gauge IC are identical across the platform.
- Bench tested on actual hardware: We ran this cell through charge and discharge cycles on GT2 46mm hardware. The BMS accepted the new cell without fault flags, fuel gauge re-calibrated after a full charge cycle, and all sensors initialised normally on wake.
- Fuel gauge re-calibration after swap: Place the watch on its magnetic charger immediately after fitting this cell and charge fully to 100% before first use. The fuel gauge IC on the GT2 platform loses its reference point when the original cell is disconnected — without a full charge from near-zero, it will report inaccurate percentages and may trigger premature low-battery shutdowns.
Why the GT2 46mm fuel gauge reads wrong after a battery swap
The GT2 46mm uses a coulomb-counting fuel gauge IC that tracks charge by integrating current over time. When the cell is physically removed, the IC loses its stored reference — it no longer knows what "full" or "empty" looks like for the new cell's impedance profile. This causes the watch to display 0%, 1%, or erratic percentages even when the cell is charged. A full charge cycle from near-zero after the swap resets the IC's upper and lower reference points and brings readings back into accuracy.
Watch not pairing with the Huawei Health app after battery replacement
Removing the battery cuts power to the BLE stack entirely, which clears the active pairing session stored in volatile memory. The phone retains the old pairing record, but the watch boots fresh with no matching session — so the Health app shows the device as unavailable or times out. Fix this by deleting the GT2 entry from your phone's Bluetooth settings, then re-pairing through the Huawei Health app from scratch. Do not attempt to reconnect from the Bluetooth menu alone — the Health app must initiate the pairing to re-establish the full data channel.