About this replacement
Emporia One / V200 — 3.7V Li-ion Replacement Battery (AK-V200)
The AK-V200 is a 3.7V Li-ion cell rated at 800mAh (2.96Wh) that fits the Emporia One, V200, and V200_001_SG smartphones. It replaces the original battery when the phone no longer holds a charge or fails to power on. This cell matches the original's footprint at 44.50 × 40.00 × 5.30mm, so it seats without modification.
- One, V200, and V200_001_SG compatibility: These three model designations share the same PCB layout, connector pitch, and BMS handshake protocol — the AK-V200 part number covers all three without any adapter or modification to the flex connector.
- Bench tested on actual hardware: We cycled this cell through charge and discharge on a V200 unit. The BMS accepted the cell without a protection trip, and the charge IC reached full termination voltage cleanly on the first cycle.
- Fuel gauge recalibration on first use: After fitting this cell, run one complete discharge down to automatic shutdown — do not interrupt it — then charge to 100% uninterrupted. This gives the fuel gauge IC one full reference cycle against the new cell's discharge curve before the OS starts reading percentage.
Why the Emporia One reports wrong battery percentage after a cell swap
The fuel gauge IC on the V200 board tracks charge state using a coulomb counter calibrated to the original cell's internal resistance and discharge curve. A new cell has a different impedance profile, so the counter starts reporting against the wrong baseline. The OS reads these figures and displays a percentage that does not match actual charge. One uninterrupted full discharge-to-shutdown followed by a full charge resets the counter to the new cell's curve and corrects the display.
Sudden shutdown at 20–30% remaining on the replacement cell
This happens when the modem or display pulls a current spike that drops cell voltage below the BMS cutoff threshold — even though the reported percentage still looks healthy. On a freshly installed cell, the fuel gauge IC has not yet mapped where the voltage cliff sits for this specific cell, so the BMS trips before the counter expected it. Run one full calibration cycle first. If shutdowns continue after calibration, check that the connector is fully seated — a partial connection raises contact resistance and amplifies voltage sag under load, triggering cutoff earlier than the spec voltage of 3.0V per cell.