Alltel AS855 Replacement Battery 3.7V 1500mAh

Alltel AS855 Ignite — 3.7V Li-ion 1500mAh Replacement Battery

This is a 3.7V Li-ion cell rated at 1500mAh (5.55Wh) for the Alltel AS855 Ignite smartphone. It replaces the original battery when the cell no longer holds a charge or fails to power the device through normal use. Physical dimensions are 64.50 × 44.40 × 4.50mm — confirm these match your existing cell before fitting.

• AS855 and Ignite fitment: Both the AS855 and Ignite share the same battery bay dimensions and connector pinout, which is why a single cell covers both models. Voltage rail and contact orientation are identical across the two variants.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on the AS855 platform and confirmed the BMS handshake completes correctly. Charge acceptance was stable from the first cycle, and the protection circuit tripped as expected at both overcharge and over-discharge thresholds.
• Fuel gauge recalibration on first use: On first installation, disable fast charging and run one full discharge-charge cycle at standard rate. The AS855 fuel gauge IC is calibrated to the original cell's discharge curve — letting it map the new cell's curve before high-current charging prevents erratic percentage readings from the start.

Why the AS855 Ignite reports wrong battery percentage after a cell swap

The AS855 uses a fuel gauge IC that tracks capacity by measuring coulombs against a stored discharge curve from the original cell. When a new cell goes in, that stored curve no longer matches the actual cell chemistry and impedance. The gauge reads against the old reference, so it can show 40% when the cell is closer to 20%, or jump unexpectedly during use. One complete discharge down to auto-shutoff followed by a full charge resets the coulomb counter and lets the IC build a new reference curve for the replacement cell.

Sudden shutdown at 20–30% on the replacement cell

This is a voltage cliff issue, not a capacity problem. When the modem transmits or the screen peaks in brightness, current draw spikes and cell voltage drops sharply. If the fuel gauge IC still holds an inaccurate state-of-charge estimate from the old cell, the phone has no warning before the cell voltage crosses the shutdown threshold. The fix is the same full recalibration cycle — discharge to auto-shutoff, charge uninterrupted to 100% at standard rate. After one clean cycle, the gauge's low-battery warning triggers at the correct voltage, typically around 3.5V.