ZTE U288G Replacement Battery 3.7V 1500mAh Li-ion

ZTE U288G — 3.7V Li-ion Replacement Battery

This 3.7V 1500mAh Li-ion cell replaces the original battery in the ZTE U288G mobile phone. It fits directly into the U288G battery bay and restores power to the device when the original cell has degraded past usable capacity. Dimensions are 65.80 × 43.90 × 5.10mm — match these before installing.

• U288G platform fit: The U288G uses a removable Li-ion pack with a fixed connector pinout. This cell matches that connector and the voltage rail the phone's charge IC expects. No adapter or modification needed.
• Bench tested on actual hardware: We cycled this cell through full charge and discharge passes on the bench. The BMS engaged correctly at the low-voltage cutoff, and charge termination triggered at the expected 4.2V ceiling without overrun.
• Fuel gauge recalibration on first use: After installation, disable fast charging and run one complete discharge-to-charge cycle before normal use. The fuel gauge IC is calibrated to the old cell's discharge curve — one full cycle lets it map the new cell's actual capacity before reporting accurate percentages.

Sudden shutdown at 20–30% on the U288G after a cell swap

This happens when the fuel gauge IC has not yet mapped the new cell's voltage-to-capacity curve. The phone thinks it has 25% left, but the new cell's voltage drops sharply under screen or modem load, hitting the hardware cutoff before the OS sees it coming. It is not a defective cell — it is a calibration gap. Run two full discharge-charge cycles without interruption and the shutdowns will stop as the coulomb counter resets against real data.

OS showing erratic or jumping battery percentage after replacement

The Android fuel gauge IC stores learned capacity data from the old cell in non-volatile memory. After swapping to a new cell, those stored values no longer match the actual discharge curve, so the percentage reading jumps or stalls. The fix is a forced recalibration: drain the phone until it shuts off on its own, then charge uninterrupted to 100% without unplugging early. Repeat once more if the percentage still skips — by the second full cycle the IC overwrites the stale curve with current data.