About this replacement
Vodafone 888N / Smart 4 Series — 3.7V Li-ion Replacement Battery (CPLD-315)
This is a 3.7V, 1800mAh Li-ion replacement battery for the Vodafone 888N, 889N, 890N, and Smart 4 series smartphones. OEM part number CPLD-315. It physically matches the original cell at 60.70 × 56.25 × 5.20mm and connects to the same board-side connector.
- 888N / 889N / 890N and Smart 4 compatibility: These models share the same voltage rail, connector pinout, and BMS handshake protocol. All run a 3.7V nominal Li-ion cell at this physical footprint, so one cell revision covers the full lineup without modification.
- Bench tested on actual hardware: We cycled this cell through a full discharge and charge sequence on a 888N unit. The BMS accepted the new cell, balancing started within the first charge cycle, and the charge IC held the correct 4.2V cutoff at full capacity.
- Fuel gauge recalibration on first use: After installation, disable fast charging and complete one full discharge-to-charge cycle at standard current. This lets the fuel gauge IC map its coulomb counter against the new cell's discharge curve before high-current charging is introduced to an uncalibrated cell.
Sudden shutdown at 20–30% on the Vodafone 888N after a cell swap
This happens because the fuel gauge IC is still reading the old cell's discharge curve. The new cell hits a voltage cliff — often around 3.5V under modem or screen load — before the gauge reaches 0%. The phone interprets the voltage drop as an immediate low-battery shutdown rather than a gradual drain. One full discharge-to-zero and recharge cycle forces the coulomb counter to recalibrate against the actual new cell behaviour.
OS reporting incorrect battery percentage after replacement
The Android fuel gauge IC on the 888N stores learned capacity data from the old cell in firmware registers. When a new cell goes in, those stored values no longer match actual cell chemistry, so reported percentage drifts — jumping erratically or freezing at a fixed value. Drain the phone completely until it shuts down automatically, then charge uninterrupted to 100% without interruption. After one complete cycle, the fuel gauge resets its baseline to the new cell's actual full-charge voltage of 4.2V.