BLP695 Oppo Realme U1 Replacement Battery 3.85V 3400mAh

Oppo Realme U1 (RMX1833) — 3.85V Li-Polymer Replacement Battery (BLP695)

The BLP695 is the OEM-matched Li-Polymer cell for the Realme U1 (RMX1833 / R1833) smartphone. It replaces the original battery at 3.85V and 3400mAh (13.09Wh). If your Realme U1 is shutting down unexpectedly or no longer holds a charge, this cell addresses the degraded original.

• RMX1833 / R1833 compatibility: Both model codes are the same hardware revision. The BLP695 shares the same flex connector position, BMS pin-out, and 77.15 × 64.16 × 3.92mm footprint — the fuel gauge IC on the board reads this cell without modification.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on the Realme U1 board. The BMS accepted the cell on first connection, thermal cutoff triggered correctly at the upper charge threshold, and coulomb counting stabilised after one full cycle.
• Fuel gauge recalibration on first use: Disable fast charging for the first complete discharge-charge cycle after fitting this cell. The fuel gauge IC is still mapped to the old cell's discharge curve. One slow cycle at standard current lets it recalibrate before high-current charging begins on an uncalibrated cell.

Sudden shutdown at 20–30% on the Realme U1 after a cell swap

This happens because the fuel gauge IC still holds the discharge curve of the old, degraded cell. When the Realme U1 fires the modem at full signal search or drives the display at peak brightness, current draw spikes sharply. The new cell's actual voltage at that load drops below what the old curve predicts for 20–30%, triggering an emergency shutdown. One full discharge-to-shutdown followed by a complete charge resets the coulomb counter to the new cell's profile and eliminates these premature cutoffs.

USB fast charge not activating on first cycle after fitting the BLP695

On the first connection after installation, the charge IC on the Realme U1 board runs a brief handshake check against the new cell's BMS. If the cell has been in storage, its resting voltage may sit below 3.6V, and the controller falls back to trickle mode rather than engaging fast charge. Let the phone charge uninterrupted at standard rate until it crosses 3.7V per cell — fast charge will then engage automatically. Forcing a fast-charge connection before that threshold can trip the overcurrent protection in the BMS.