About this replacement
Huawei Watch 1 — 3.8V Li-Polymer Replacement Battery (HB442528EBC)
This 3.8V, 270mAh Li-Polymer cell is a direct cell replacement for the Huawei Watch 1 smartwatch. It matches the OEM part number HB442528EBC and fits the original battery bay at 27.50 x 24.00 x 3.50mm. If your Watch 1 no longer holds charge through a day of normal use, this cell addresses the degraded capacity in the original.
- Huawei Watch 1 platform fit: The Watch 1 runs a single-cell 3.8V Li-Polymer architecture. This cell matches that voltage rail and the flex connector orientation the watch's charging and power management IC expects. No adapter or modification is needed.
- Bench tested on actual hardware: We ran this cell through charge and discharge cycles on the Watch 1 platform. The BMS accepted the new cell without flagging a fault, and the fuel gauge IC tracked state-of-charge correctly after a full conditioning cycle from near-zero.
- Post-swap charge requirement: After fitting this cell, place the watch on its magnetic charger immediately and run it to 100% before first use. The fuel gauge IC on the Watch 1 loses its reference point when the cell is swapped. Without a full charge cycle from near-zero, the percentage reading will be inaccurate from the first use.
Why the Watch 1 reports wrong battery percentage after a cell swap
The Watch 1 uses a coulomb-counting fuel gauge IC that tracks charge in and out of the cell over time. When the original cell is removed, the IC loses its accumulated reference data. It cannot accurately estimate capacity on a new cell without recalibrating. One full charge from near-zero to 100% gives the IC the reference point it needs to report correctly going forward.
Watch not pairing with phone after battery replacement
Removing the battery kills the BLE stack mid-session. The phone retains the old pairing record, but the watch boots with no active session — so the two devices see each other as unrecognised. The fix is to remove the watch from your phone's Bluetooth settings entirely, then re-initiate pairing through the Huawei Health app from scratch. Do not just tap "connect" on an existing entry — delete it first, then pair fresh.