Amazing A2 3.7V 1600mAh Replacement Battery Li-ion

Amazing A2 — 3.7V Li-ion 1600mAh Replacement Battery

This is a 3.7V, 1600mAh Li-ion replacement battery for the Amazing A2 smartphone. It fits directly into the A2 and restores power when the original cell has degraded or failed. Capacity is 5.92Wh as rated from the cell specification.

• Amazing A2 fit: The A2 uses a single-cell 3.7V nominal Li-ion configuration. This replacement matches that voltage rail and the physical dimensions of the original cell — 59.40 x 46.00 x 5.10mm — so the connector aligns and the BMS on the phone's charge IC communicates correctly.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on the bench, monitoring BMS handshake and cutoff behaviour. The protection circuit triggered correctly at low-voltage threshold and accepted charge current without error flags on the first full cycle.
• Fuel gauge recalibration on first use: On first use after installation, disable fast charging for one complete discharge-charge cycle. This gives the A2's fuel gauge IC time to map the new cell's discharge curve before high-current charging pushes into an uncalibrated state. One slow cycle prevents erratic percentage readings later.

Why the A2 reports wrong battery percentage after a cell swap

The A2's fuel gauge IC stores a learned discharge curve from the original cell. When a new cell goes in, that stored curve no longer matches the actual cell chemistry, so the reported percentage drifts from real charge state. The IC needs at least one full discharge down to the low-voltage cutoff — around 3.0V — followed by a complete charge to 4.2V to re-anchor its coulomb counter. Until that cycle completes, the percentage readout will lag or jump. Run one full cycle before trusting the displayed percentage.

Sudden shutdown at 20–30% on the replacement cell

This happens when the A2's modem or display draws a current spike the new cell cannot sustain at that state of charge, causing cell voltage to sag below the BMS cutoff threshold even though the gauge still reads 20–30%. It is a voltage cliff — not a capacity problem. A full calibration cycle as described above usually shifts the cutoff point to a more accurate state-of-charge reading. If shutdowns continue after calibration, check that the connector is fully seated and cell voltage at rest reads at least 3.7V with a multimeter before reinstalling.