Oppo RMX1901 Compatible Battery BLP713 3.85V 4000mAh

Oppo RMX1901 / Realme X — 3.85V Li-Polymer Replacement Battery (BLP713)

The BLP713 is the OEM-spec Li-Polymer cell for the Oppo RMX1901 and Realme X smartphones. It runs at 3.85V and delivers 4000mAh (15.4Wh) of capacity. This battery replaces the original when the phone can no longer hold a charge through normal daily use.

• RMX1901 and Realme X compatibility: Both devices share the same motherboard platform, connector pinout, and BMS handshake protocol — one cell fits both without adaptation.
• Bench tested on actual hardware: We cycled the BLP713 through charge and discharge on the RMX1901 motherboard. The BMS accepted the cell, charge termination triggered at the correct 4.40V cutoff, and protection thresholds behaved within spec.
• Fuel gauge recalibration on first use: After installation, disable fast charging and run one complete discharge-to-charge cycle at standard current. This lets the coulomb counter IC map its reference curve against the new cell before high-current VOOC charging pushes current into an uncalibrated state.

Sudden shutdown at 20–30% after swapping the BLP713

This happens because the fuel gauge IC still holds 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. When voltage drops sharply at 20–30% reported charge, the IC interprets it as a cutoff event and shuts the phone down. One full discharge to 0% followed by an uninterrupted charge to 100% resets the coulomb counter and eliminates the false shutdown trigger.

VOOC fast charge not activating on the first cycle after replacement

VOOC requires a handshake between the charger, the charge IC, and the battery BMS. On the first cycle with a new cell, the BMS may present higher internal impedance than the charge IC expects, causing it to fall back to standard 5V/1A charging as a safety measure. This is not a fault with the battery or charger. Complete one full standard-current charge cycle — the charge IC will re-establish the VOOC handshake on subsequent connections once the cell impedance settles below the threshold.