Philips Xenium 9A9A Compatible Battery 3.7V 1100mAh

Philips Xenium 9A9A / 9@9D — 3.7V Li-ion Replacement Battery (A20ZCK/COP)

This is a 3.7V, 1100mAh Li-ion cell replacing OEM part A20ZCK/COP in the Philips Xenium 9A9A and Xenium 9@9D smartphones. It fits the original battery bay without modification. Capacity figures come from the product data — 1100mAh / 4.07Wh.

• Xenium 9A9A and 9@9D compatibility: Both models share the same battery bay dimensions, connector pinout, and BMS handshake requirements. One cell — OEM part A20ZCK/COP — covers both variants without any wiring or adapter changes.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on a Philips Xenium platform. The BMS accepted the cell without fault flags, and charge termination triggered correctly at full voltage with no thermal events.
• First-cycle fuel gauge reset: After installing this cell, disable fast charging 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 high-current charging pushes into an uncalibrated state — preventing percentage jumps and early shutdowns.

Sudden shutdown at 20–30% on the Xenium 9A9A after a cell swap

A new Li-ion cell has a slightly different discharge curve than the worn cell the fuel gauge IC was calibrated against. When the phone draws a surge — modem transmitting, screen at full brightness — the cell voltage can dip below the BMS cutoff threshold even though the OS still reports 25% remaining. The phone reads fuel gauge data, not raw cell voltage, so it shuts down before the percentage hits zero. One full discharge cycle (run the phone to auto-off, then charge to 100% at standard rate) lets the coulomb counter recalibrate against the actual cell, and the shutdowns stop.

Phone warm near the battery during the first few charges

A new cell typically has higher internal impedance than a broken-in one. The charge IC pushes the same current regardless, so slightly more energy converts to heat across that higher resistance during the first few cycles. This is not a fault — impedance drops as the cell breaks in over three to five cycles. If the phone stays warm past the fifth full charge, check that the back cover is seated flat and not trapping heat against the cell. Surface temperature above 45°C on the back casing warrants stopping the charge and inspecting the connector seating.