Amazing A5s Replacement Battery Li3818T43P3h665344 3.7V 1500mAh

Amazing A5s — 3.7V Li-ion Replacement Battery (Li3818T43P3h665344)

This is a 3.7V, 1500mAh Li-ion replacement battery for the Amazing A5s smartphone. It carries OEM part number Li3818T43P3h665344 and slots directly into the A5s battery bay. Capacity and voltage match the original cell specification.

• Amazing A5s compatibility: The A5s uses a single-cell 3.7V nominal Li-ion architecture with a fixed connector pinout. This cell matches that voltage rail and connector layout, so the phone's charge IC and BMS handshake proceed without flagging an incompatible cell.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on a test rig monitoring BMS cutoff thresholds. The protection circuit tripped correctly at the low-voltage floor and accepted a full charge without thermal events or charge IC rejection.
• Fuel gauge recalibration on first use: On first use after installation, disable fast charging for one complete discharge-charge cycle. This lets the fuel gauge IC map the new cell's actual discharge curve before high-current charging pushes current into an uncalibrated cell — reducing the risk of erratic percentage readings early on.

Why the A5s reports wrong battery percentage after a cell swap

The A5s uses a coulomb counter that builds its charge model against the original cell's discharge curve over many cycles. When a new cell goes in, that learned curve no longer matches the physical reality of the fresh cell. The fuel gauge IC hasn't yet logged enough cycle data to recalibrate, so it can read 15% high or low. One full discharge-to-shutdown followed by an uninterrupted charge to 100% gives the IC enough data to reset its baseline.

Sudden shutdown at 20–30% on the replacement cell

This happens when the cell voltage drops sharply under load — typically when the modem transmits or the screen hits full brightness — faster than the fuel gauge IC predicted. The phone hits the hardware voltage floor (around 3.2V under load) before the reported percentage reaches zero, so it shuts down mid-use. The fix is to let the phone run down to automatic shutdown twice in a row without interruption. After two full discharge cycles, the coulomb counter narrows its error margin and the early-shutdown behaviour typically stops.