About this replacement
Ticwatch Pro / Pro 4G — 3.85V Li-Polymer Replacement Battery (SP452929SF)
This is a 3.85V, 400mAh Li-Polymer cell (SP452929SF) for the Ticwatch Pro and Pro 4G smartwatch. It replaces the original cell when capacity fade causes noticeably shorter battery life between charges. Dimensions are 27.30 × 27.70 × 4.30mm — confirm your existing cell matches before ordering.
- Pro and Pro 4G compatibility: Both models share the same 3.85V battery bay, connector pinout, and BMS handshake. The SP452929SF part number covers both variants — no hardware modification needed to fit either watch.
- Bench tested on actual hardware: We cycled this cell through charge and discharge on the Pro platform and confirmed the BMS accepted the new cell without triggering a protection cutoff. The fuel gauge IC re-calibrated correctly after a full charge from near-zero.
- Fuel gauge reset after swap: Place the watch on its magnetic charger immediately after fitting this cell and charge to 100% before first use. The fuel gauge IC on the Pro platform cannot set an accurate reference point without a complete charge cycle from near-zero following a cell replacement.
Why the Ticwatch Pro 4G drains faster with always-on display and continuous HR active
The Pro 4G runs a dual-display stack — an FSTN layer for ambient mode and an AMOLED layer for full colour. When both are active alongside continuous heart rate polling, the combined draw is significantly higher than single-display smartwatches at the same capacity. The HR sensor fires at short intervals to maintain a continuous reading, and each poll adds a measurable current spike. On a 400mAh cell, this combination will shorten the charge interval compared to lighter usage profiles. Switching HR to on-demand rather than continuous is the fastest way to extend time between charges on this platform.
Watch not pairing to phone after battery replacement
Removing the battery terminates the active BLE session without a clean shutdown. The phone retains the old pairing record, but the watch starts fresh with no session state — the two devices no longer share a valid bond key. Simply restarting Bluetooth on the phone will not resolve this. Open the Mobvoi app, remove the existing device entry, then re-pair from scratch through the app's add-device flow to re-establish a clean BLE bond.