Oppo BLPB49 CPH2689 Replacement Battery 3.92V 5450mAh

Oppo Reno13 / CPH2689 — 3.92V Li-Polymer Replacement Battery (BLPB49)

This is a 5450mAh Li-Polymer cell at 3.92V nominal, built to replace the BLPB49 battery in the Oppo CPH2689, PKM110, Reno13, and Reno13 5G. These four models share the same battery bay dimensions, connector pinout, and BMS communication protocol. Capacity figures are taken directly from product specifications — 21.36Wh total energy.

• CPH2689 / Reno13 platform fit: All four listed models run the same voltage rail and use an identical flex connector with matching BMS handshake signals. Swapping between any of these variants does not require firmware changes or connector adapters.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on Reno13 hardware. The BMS accepted the cell without fault flags, and the charge IC progressed through CC-CV stages correctly without terminating early.
• Fuel gauge recalibration on first use: On first use after installation, disable fast charging and run one complete discharge-charge cycle at standard rate. This lets the fuel gauge IC map its coulomb counter against the new cell's actual discharge curve before high-current charging is introduced into an uncalibrated cell.

Sudden shutdown at 20–30% on the replacement cell

A new Li-Polymer cell has a steeper voltage-versus-capacity curve than a worn original. Under modem load or sustained screen-on use, the cell voltage drops sharply — faster than the fuel gauge IC expects. The phone's low-voltage protection trips before the gauge reaches 0%, and the device cuts out. One full discharge cycle lets the fuel gauge IC recalibrate its internal model to the new cell's curve. After that cycle, shutdowns at 20–30% typically stop. If they persist, check that the connector is fully seated — a loose pin causes intermittent voltage reads that also trigger early cutoff.

VOOC or fast charge not activating after battery replacement

Oppo's proprietary fast charge protocol includes a BMS authentication handshake on the first charge cycle after a cell swap. Until that handshake completes, the charge IC defaults to standard 5V input and ignores fast charge negotiation. Plug in the original Oppo charger and cable — third-party cables often lack the D+/D- signalling needed to complete the handshake. Let the first charge run to 100% without interruption. On the second charge cycle, fast charging should activate normally.