Dopod C720 Compatible Battery 3.7V 1050mAh EXCA160

Dopod C720 / C720W — 3.7V Li-ion Replacement Battery (EXCA160)

This is a 3.7V 1050mAh Li-ion cell for the Dopod C720 and C720W Windows Mobile smartphones. It replaces OEM part numbers EXCA160 and 35H00080-00M. The cell matches the original's physical footprint at 54.20 × 35.80 × 5.60mm and drops into the stock battery bay without modification.

• C720 and C720W compatibility: Both handsets share the same battery bay dimensions, connector pinout, and charge IC interface. The C720W adds Wi-Fi but draws from the same 3.7V rail, so a single cell covers both variants without any hardware difference in the battery circuit.
• Bench tested on actual hardware: We cycled this cell through full charge and discharge passes on the C720 platform. The BMS held the charge cutoff correctly at 4.2V and the protection circuit tripped at the expected low-voltage threshold before cell damage could occur.
• Fuel gauge recalibration on first cycle: After fitting this cell, run one complete discharge down to automatic shutdown, then charge uninterrupted to 100% before normal use. The C720's fuel gauge IC maps its coulomb counter against a fresh discharge curve on the first cycle — skipping this step causes percentage readouts to drift by 15–25% for weeks.

Sudden shutdown at 20–30% on the Dopod C720

The C720's charge IC holds a lookup table calibrated to the original cell's internal resistance curve. A new cell has lower impedance, so the fuel gauge reports a higher remaining percentage than the cell can actually sustain under load. When the modem transmits or the backlight peaks, voltage sags below the BMS cutoff threshold — the phone shuts off even though the OS showed charge remaining. One full discharge-recharge cycle lets the coulomb counter relearn the new cell's actual voltage-versus-capacity curve and eliminates the false floor.

Battery percentage jumping erratically after cell replacement

Erratic percentage jumps — such as dropping from 60% to 35% in seconds or climbing without charging — mean the fuel gauge IC is still running its algorithm against the old cell's discharge profile. This is a software calibration state, not a fault with the replacement cell. Force the recalibration by discharging the phone to automatic shutdown, then charging continuously to 100% with the screen off. After one clean cycle, the percentage stabilises and tracks linearly against actual capacity.