About this replacement
TCL P561U — 3.8V Li-Polymer Replacement Battery (TLp028CF)
This is a 3.8V, 3100mAh Li-Polymer battery for the TCL P561U smartphone. It replaces part number TLp028CF — the original cell that powers calling, messaging, and on-device applications. If your P561U is shutting down unexpectedly or draining fast, this is the direct cell swap.
- TCL P561U fitment: The P561U uses the TLp028CF cell across its single hardware revision. Voltage rail, connector pitch, and BMS handshake are matched to this spec — no adapters or modification needed.
- Bench tested on actual hardware: We ran this cell through charge and discharge cycles on the P561U platform. The BMS accepted the cell without triggering a fault state, and charge current ramped correctly through both trickle and CC/CV phases.
- Fuel gauge recalibration on first use: Disable fast charging for the first complete discharge-charge cycle after installation. This lets the fuel gauge IC map its coulomb counter against the new cell's actual discharge curve before high-current charging begins on an uncalibrated reference.
Sudden shutdown at 20–30% on the TCL P561U after a cell swap
A new cell has a different internal impedance curve than the aged cell the fuel gauge IC was calibrated to. Under modem load or screen-on current draw, voltage dips sharply at the knee of the discharge curve — the phone hits a low-voltage threshold before the percentage indicator reaches zero. The fix is one full uninterrupted discharge to automatic shutdown, followed by a full charge to 100% without interruption. After that cycle, the coulomb counter resets to the new cell's actual capacity baseline.
USB fast charge not working on the P561U after battery replacement
On the first cycle after a cell swap, the charge IC on the P561U may negotiate a lower charge rate while the BMS validates the new cell. This is normal behaviour — the controller defaults to standard 5V/1A until it confirms cell temperature and impedance are within spec. Plug in, let the first full charge complete without unplugging early, and fast charge negotiation should resume normally on the second cycle. If it does not, check that the battery connector is fully seated, as a partial connection raises measured impedance above the fast-charge acceptance threshold.