Cricket Debut LT25H426271W Replacement Battery 3.85V 2700mAh

Cricket Debut / U319AA — 3.85V Li-Polymer Replacement Battery (LT25H426271W)

This 3.85V, 2700mAh Li-Polymer battery replaces part number LT25H426271W in the Cricket Debut (U319AA) smartphone. It fits the original battery bay and connects to the same charge IC the phone uses to manage cell voltage and fuel gauge data. Capacity is 2700mAh — 10.4Wh total energy.

• Debut / U319AA platform fit: Both model designations share the same physical cell dimensions, connector pinout, and BMS handshake. The charge IC expects the same voltage curve this cell delivers, so the phone recognises the battery without a firmware prompt.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on the Debut platform. The BMS accepted the cell on first connection, held charge current stable through the CV phase, and terminated correctly at full charge without tripping the protection circuit.
• Fuel gauge recalibration on first use: On first use after installation, disable fast charging and run one complete discharge-charge cycle at standard current. This lets the fuel gauge IC map the new cell's discharge curve before high-current charging pushes energy into an uncalibrated state model.

Sudden shutdown at 20–30% on the replacement cell

This happens because the fuel gauge IC still holds the discharge curve from the old, degraded cell. When the new cell hits a voltage point the old curve mapped to 20–30%, the IC signals a low-voltage shutdown even though usable charge remains. The fix is one full discharge-charge cycle with the screen on and mobile data active — this forces the coulomb counter to relearn the actual capacity. After that cycle, shutdowns at high reported percentages stop.

Battery percentage jumping erratically after install

Erratic percentage readings on the Debut after a cell swap come from the fuel gauge IC comparing live cell voltage against a stored state-of-charge table built around the old cell's impedance. A fresh Li-Polymer cell has lower internal resistance, so voltage readings land outside the expected table range and the IC interpolates incorrectly. Run the phone down to auto-shutdown, then charge uninterrupted to 100% without removing the charger. After one clean cycle, percentage readings stabilise — verify by checking that voltage at reported 50% sits near 3.83–3.85V.