About this replacement
Oppo Find X Series — 3.85V Li-Polymer Replacement Battery (BLP671)
The BLP671 is a 3.85V, 3600mAh (13.86Wh) lithium-polymer cell that fits the Oppo Find X, Find X Dual SIM, Find X Dual SIM TD-LTE, and PAFT00. It replaces a degraded or failed original cell to restore full display, processor, and wireless operation. Dimensions are 61.12 × 60.30 × 5.76mm — confirm clearance before installation.
- Find X platform fit: All listed Find X variants share the same battery bay geometry, connector pinout, and BMS handshake protocol — one cell covers the entire group without modification.
- Bench tested on actual hardware: We cycled this cell through charge and discharge on a Find X unit, confirming BMS communication, charge acceptance across the full 3.85V nominal curve, and clean cutoff at low-cell voltage.
- Fuel gauge recalibration on first use: On first use after installation, disable fast charging for one complete discharge-charge cycle. This lets the fuel gauge IC recalibrate against the new cell's discharge curve before high-current charging pushes current into an uncalibrated cell.
Why the Find X reports wrong battery percentage after a cell swap
The Find X uses a coulomb-counter fuel gauge IC that builds its capacity model against the original cell's discharge curve over hundreds of cycles. When a new cell goes in, the IC is still running the old model. The percentage readout can appear stuck, jump erratically, or plateau for long periods. One full uninterrupted discharge-to-charge cycle — without fast charging — lets the IC reset its reference table against the new cell.
Sudden shutdown at 20–30% on the replacement cell
This happens when the fuel gauge IC has not yet mapped the new cell's voltage cliff — the point where cell voltage drops sharply under modem or screen load. The phone reads 25% state of charge but the actual cell voltage under load dips below the shutdown threshold. It is not a faulty cell; it is a calibration gap. Run one full cycle without interruption and the IC will anchor its low-voltage cutoff to the correct point on the new discharge curve.