ESIA Qwerty Mini 3.7V 1100mAh Replacement Battery

ESIA Qwerty Mini — 3.7V Li-ion 1100mAh Replacement Battery

This is a 3.7V Li-ion cell rated at 1100mAh (4.07Wh), sized at 44.00 x 38.00 x 5.20mm to fit the ESIA Qwerty Mini smartphone. It replaces a degraded or failed original cell to restore normal device operation. No OEM part number is published for this battery — match by fit model before ordering.

• Qwerty Mini form factor: The Qwerty Mini uses a compact chassis with tight clearance around the cell. At 44 x 38 x 5.20mm, this cell matches the original footprint and connector orientation — no modification needed for seating.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on the Qwerty Mini platform. The BMS accepted the cell on first connection, charge current ramped normally, and the protection circuit tripped correctly at the low-voltage cutoff threshold.
• Fuel gauge recalibration on first cycle: After installation, disable any fast-charge mode and run one full discharge-to-charge cycle at standard current. This lets the fuel gauge IC map the new cell's discharge curve before the OS begins reading percentage from it.

Why the Qwerty Mini reports wrong battery percentage after a cell swap

The Qwerty Mini uses a fuel gauge IC that builds its charge model from previous cell discharge history. When you fit a new cell, the IC still references the old curve, so reported percentage drifts from actual state of charge. The mismatch is largest in the 30–70% range where the new cell's voltage profile differs most from a worn cell. One complete slow-charge cycle — from near-zero to full — resets the coulomb counter and brings percentage readings back into alignment.

Sudden shutdown at 20–30% on the replacement cell

This happens when the fuel gauge IC has not yet calibrated to the new cell and the voltage drops below the modem or display load threshold before the reported percentage reaches zero. The phone shuts down to protect the cell, even though the gauge still shows charge remaining. It is not a defective cell — it is an uncalibrated gauge cutting power at the wrong point. Discharge the phone fully once, charge to 100% without interruption, and the shutdowns will stop.