Li3712T42P3h634445 Amazing A4C Replacement Battery 3.7V 1200mAh

Amazing A4C — 3.7V Li-ion 1200mAh Replacement Battery (Li3712T42P3h634445)

This is a 3.7V lithium-ion battery rated at 1200mAh (4.44Wh) for the Amazing A4C smartphone. It replaces the original Li3712T42P3h634445 cell when the factory unit no longer holds usable charge. Fits the A4C form factor at 63.05 × 43.87 × 4.30mm.

• Amazing A4C platform fit: The A4C uses a fixed connector and BMS handshake tied to the Li3712T42P3h634445 cell specification. This replacement matches that voltage rail and physical footprint so the phone's charge IC recognises the cell correctly on first boot.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on the bench, monitoring BMS cutoff at low voltage. The protection circuit tripped correctly at the expected floor and accepted a full charge without thermal event.
• Fuel gauge recalibration after swap: On first use after installation, disable fast charging and run one complete discharge-to-charge cycle. This lets the A4C's fuel gauge IC map the new cell's discharge curve before high-current charging begins on an uncalibrated cell.

Sudden shutdown at 20–30% on the Amazing A4C after cell replacement

The A4C's fuel gauge IC retains the discharge curve from the original cell. When a new cell goes in, the gauge's stored curve no longer matches actual cell voltage under load. The modem and screen draw spikes that the new cell cannot sustain at the voltage the gauge predicts — so the phone cuts out even though the reported percentage looks safe. One full discharge below 5% followed by a full charge to 100% forces the coulomb counter to reset against the real cell capacity.

Battery percentage jumping erratically in the first two days after installation

Erratic percentage readouts are a fuel gauge recalibration symptom, not a faulty cell. The coulomb counter is still comparing current measurements against the old cell's stored data points. Each full charge-discharge cycle overwrites one reference point in that curve. After two to three full cycles the readings stabilise — if they do not, confirm the replacement cell rests at 3.6–3.8V open-circuit before the next charge.