Diesel DZT2002 Smartwatch Compatible Battery 3.8V 370mAh

Diesel DZT2002 — 3.8V Li-Polymer Replacement Battery (APP00222)

This is a 3.8V, 370mAh lithium-polymer cell for the Diesel DZT2002 smartwatch. It replaces OEM part APP00222 and restores power to timekeeping, notifications, heart rate monitoring, and Bluetooth connectivity. Dimensions are 31.00 × 26.00 × 4.00mm — measure your existing cell before fitting if the watch has been previously repaired.

• DZT2002 platform fit: The DZT2002 uses a flat Li-Polymer pouch cell with a specific connector orientation tied to the watch's power management IC. This cell matches that connector and the BMS voltage thresholds the board expects at startup.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on a DZT2002-class board. The BMS accepted the cell without fault flags, and the fuel gauge IC initialised correctly after a full charge from near-zero.
• Fuel gauge calibration after swap: Place the watch on its charger immediately after fitting this cell and charge to 100% before first use. The fuel gauge IC on the DZT2002 loses its reference point when the original cell is removed and cannot calibrate accurately without a complete charge cycle starting from near-zero.

Why the DZT2002 shows 0% immediately after a battery swap

The DZT2002 uses a coulomb-counting fuel gauge IC that tracks charge state relative to a stored reference. Removing the old cell wipes that reference from volatile memory. When the new cell is fitted, the IC has no baseline and defaults to 0% or shuts down the display to protect the cell. This is not a fault with the replacement cell. Charge the watch fully from near-zero and the IC will re-establish its reference — the percentage reading will then track correctly.

Charge contacts not engaging on the magnetic charger after reassembly

If the watch does not respond when placed on its magnetic charger after a cell swap, the charge contacts on the case back have likely shifted slightly during reassembly. Even a 0.5mm misalignment is enough to break contact with the charger's magnetic pins. Re-seat the back cover and press firmly at each corner until it clicks flush. Confirm alignment by checking that the charger indicator lights within 10 seconds of placement.