OnePlus 9 Pro 5G Replacement Battery BLP827 7.4V 2200mAh

OnePlus 9 Pro 5G — 7.4V Li-Polymer Replacement Battery (BLP827)

This is a 7.4V, 2200mAh Li-Polymer replacement battery for the OnePlus 9 Pro 5G smartphone. It fits models LE2120, LE2121, LE2123, and related variants. Install it when the original BLP827 cell no longer holds a usable charge or fails to power the device at all.

• LE2120 / LE2121 / LE2123 platform fit: These model numbers share the same physical cell bay, connector pinout, and BMS handshake protocol. The BLP827 part number covers all of them — no hardware variation between these SKUs affects battery compatibility.
• Bench tested on actual hardware: We ran this cell through a full charge cycle on an LE2121 unit. The BMS accepted the cell without flagging an unrecognised source, charge current stepped correctly through CC and CV phases, and cutoff triggered cleanly at 8.4V.
• 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 Warp Charge pushes high current into an uncalibrated cell.

Sudden shutdown at 20–30% on the replacement cell

A new cell has a discharge curve the phone's coulomb counter has never seen before. When the modem fires during a 5G handoff or the AMOLED panel peaks in brightness, current draw spikes hard. If the fuel gauge IC still maps the old cell's curve, it can misread remaining capacity by 15–20%. The phone's protection logic sees voltage drop below threshold and cuts power — even though the cell physically has charge left. One full uninterrupted discharge to auto-shutdown, followed by a complete charge to 100%, resets the coulomb counter to the new curve.

Warp Charge not activating after cell replacement

OnePlus Warp Charge requires a handshake between the charger, the charge IC on the board, and the battery BMS. On the first cycle after a cell swap, the BMS may not complete that handshake immediately, and the phone falls back to standard 5W USB charging. This is not a fault — it resolves after one full standard charge cycle. If Warp Charge still does not activate after two full cycles, check that the battery flex connector is fully seated and the lock tab is clicked down flat.