Amazing A1 3.7V 1200mAh Li-ion Compatible Battery

Amazing A1 — 3.7V Li-ion Replacement Battery

This 3.7V 1200mAh Li-ion battery replaces the original cell in the Amazing A1 smartphone. It measures 49.00 × 47.80 × 5.50 mm and delivers 4.44Wh of capacity. Fit the original connector and the phone powers on as normal.

• A1 platform fitment: The A1 uses a single-cell 3.7V nominal Li-ion architecture. This replacement matches that voltage rail and physical footprint, so the BMS handshake between the charge IC and the cell completes without fault codes.
• Bench tested on actual hardware: We cycled this cell through full charge and discharge on the A1 platform. The BMS accepted the cell on first connect, the charge IC ramped current correctly, and the fuel gauge IC began tracking state-of-charge without error flags.
• First-cycle fast charge protocol: On first use after installation, disable fast charging for one complete discharge-charge cycle. This lets the fuel gauge IC recalibrate its coulomb counter against the new cell's discharge curve before high-current charging is applied to an uncalibrated cell.

Why the A1 reports wrong battery percentage after a cell swap

The fuel gauge IC on the A1 stores a learned discharge curve from the old cell. When a new cell goes in, that stored curve no longer matches the actual voltage-to-capacity relationship of the replacement. The phone reads a voltage, maps it to the old curve, and displays a percentage that drifts or jumps. One full discharge down to auto-off followed by a full uninterrupted charge resets the coulomb counter and the gauge IC recalibrates to the new cell.

Sudden shutdown at 20–30% on the replacement cell

This happens when the modem or display triggers a high-current draw spike and the cell voltage drops below the BMS cutoff threshold — even though the gauge IC still shows charge remaining. The old stored curve tells the phone there is capacity left, but the cell voltage under load has already collapsed past 3.0V. One full calibration cycle corrects the gauge IC's low-end voltage map. After calibration, the phone's shutdown point aligns with the actual cell floor at approximately 3.2V under load.