About this replacement
Oppo A91 / F15 2020 — 3.85V Li-Polymer Replacement Battery (BLP765)
This is a 3800mAh Li-Polymer cell at 3.85V, built to the BLP765 specification. It fits the Oppo A91, F15 2020, PCPM00, and CPH2001 variants. Swap it in when the original cell no longer holds a usable charge across a full day.
- A91 / F15 2020 platform fit: These four model codes — A91, PCPM00, F15 2020, CPH2001 — share the same mainboard layout, connector pinout, and BMS handshake protocol, which is why a single BLP765 cell covers all of them without modification.
- Bench tested on actual hardware: We ran the BLP765 through charge and discharge cycles on the CPH2001 board. The BMS accepted the cell on first connection, charge termination fired correctly at 4.35V, and the fuel gauge IC initialised without error flags.
- Fuel gauge recalibration on first use: After installation, disable VOOC fast charging for one complete discharge-to-charge cycle. This gives the fuel gauge IC time to map the new cell's discharge curve before high-current charging begins on an uncalibrated cell.
Sudden shutdown at 20–30% on the A91 after a cell swap
This happens when the fuel gauge IC is still using the discharge curve from the old, degraded cell. The new cell has a steeper voltage cliff under modem and display load than the IC expects, so it reads 25% right up until the cell voltage drops below the shutdown threshold. The fix is a full manual calibration cycle — drain the phone until it powers off, then charge uninterrupted to 100% without using the phone. After one clean cycle, the coulomb counter resets to the new cell's actual capacity and the early shutdown stops.
VOOC fast charging not engaging after BLP765 installation
On the first charge cycle after a cell swap, the charge IC on the A91 runs a handshake verification before it allows VOOC current. If the BMS on the replacement cell has not yet completed its initialisation sequence, the IC falls back to standard 5V charging as a precaution. Plug into a VOOC-compatible charger and let the first full charge run without interruption — do not unplug partway through. By the second cycle, the handshake completes and VOOC engages normally.