About this replacement
Oppo A52 / CPH2061 — 3.85V Li-Polymer Replacement Battery (BLP781)
This 3.85V, 3000mAh Li-Polymer cell replaces the original BLP781 battery in the Oppo A52 (CPH2061). It restores power to a phone that no longer holds charge through a normal day. Voltage and dimensions match the original: 88.40 × 62.43 × 4.00mm.
- A52 and CPH2061 fitment: Both model references share the same PCB layout, BMS handshake protocol, and BLP781 connector pinout — one cell covers both variants without modification.
- Bench tested on actual hardware: We ran this cell through charge and discharge cycles on the A52 platform. The BMS accepted the cell without error flags, and the charge IC progressed normally through CC and CV phases.
- Fuel gauge recalibration after swap: 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 discharge curve before high-current charging pushes current into an uncalibrated coulomb counter.
Sudden shutdown at 20–30% on the replacement cell
This happens when the fuel gauge IC is still calibrated to the old cell's discharge curve. The phone reads 25% remaining, but the new cell's actual voltage under modem and screen load drops faster than the old curve predicts. The system hits its low-voltage cutoff before the gauge catches up. One full discharge-charge cycle with fast charging disabled forces the coulomb counter to recalibrate — after that, the percentage readout tracks correctly.
VOOC fast charge not activating on the first cycle after replacement
Oppo's VOOC protocol requires the charge IC to confirm cell impedance is within an expected range before switching to high-current mode. A new cell can present slightly elevated impedance on cycle one, causing the charger to fall back to standard 5V/1A input. This is not a fault with the cell or the adapter. Complete one full standard charge cycle — impedance normalises and VOOC re-engages on the next charge without any further action.