Dopod C720 EXCA160 Replacement Battery 3.7V 2200mAh

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

This 3.7V 2200mAh Li-ion cell replaces the original EXCA160 battery in the Dopod C720 and C720W Windows Mobile smartphones. It restores power for calls, messaging, and app use on these mid-2000s devices. Capacity is 2200mAh (8.14Wh) — drawn from the product specification, not estimated.

• C720 and C720W compatibility: Both models share the same battery bay dimensions, connector pinout, and 3.7V single-cell architecture. The EXCA160 part number covers both variants — no hardware modification needed to fit either device.
• Bench tested on actual hardware: We cycled this cell through full charge and discharge on the C720 platform. The BMS engaged correctly at low voltage cutoff, and charge termination triggered at the expected voltage without overrun.
• Fuel gauge recalibration on first use: After installing this cell, run one complete discharge-to-charge cycle before enabling any fast-charge option. The fuel gauge IC on the C720 was calibrated to the original cell's discharge curve — one full cycle lets it recalibrate against the new cell before high-current charging begins.

Why the C720 reports wrong battery percentage after a cell swap

The C720 uses a fuel gauge IC that tracks charge by modelling the original cell's discharge curve. A new cell has a different internal resistance profile, so the IC's stored model no longer maps accurately to real voltage. The phone may show 80% when the cell is nearly flat, or drop suddenly to 10% from a high reading. One full discharge-to-charge cycle forces the IC to re-anchor its calibration to the new cell.

Sudden shutdown at 20–30% on the Dopod C720

This is a voltage-cliff failure — not a capacity problem. When the screen backlight, GSM modem, and CPU all draw current simultaneously, a degraded or poorly calibrated cell cannot hold voltage under that combined load. The BMS reads voltage drop as a cutoff condition and shuts the device down even though the fuel gauge still shows charge remaining. Charge the device to 100%, run one full cycle, then check whether the reported percentage at shutdown has stabilised above 10V — if the problem persists, the fuel gauge IC needs a second full cycle to finish recalibration.