BLP911 Oppo Realme V25 Replacement Battery 3.87V 4900mAh

Oppo Realme V25 / Realme 9i / K10 — 3.87V Li-Polymer Replacement Battery (BLP911)

The BLP911 is a 3.87V, 4900mAh Li-Polymer cell that replaces the original factory battery in the Realme V25, Realme 9i, K10, and CPH2373. It matches the OEM footprint at 93.75 × 65.00 × 4.50mm and connects to the existing charge IC and fuel gauge IC without modification. Capacity is 18.96Wh.

• Realme V25 / 9i / K10 platform fit: These four models share the same BLP911 connector pinout, BMS handshake protocol, and charge IC voltage rails. One cell covers all four variants without adapter wiring or firmware changes.
• Bench tested on actual hardware: We cycled BLP911 units through full charge and discharge on a Realme 9i test unit. The BMS accepted the charge IC handshake on the first cycle, held voltage above 3.6V through mid-discharge, and tripped thermal protection correctly at the rated cutoff threshold.
• 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 gives the fuel gauge IC time to map the new cell's discharge curve before high-current fast charging pushes current into an uncalibrated coulomb counter.

Sudden shutdown at 20–30% on the Realme V25 after a cell swap

This is a voltage cliff issue, not a capacity defect. Under peak modem or display load, the new cell's internal resistance causes a voltage dip the old fuel gauge curve did not predict. The phone's under-voltage protection triggers a hard shutdown even though the reported percentage looks safe. One full discharge-charge cycle at standard rate resets the coulomb counter and eliminates the false cutoff point.

USB-PD fast charge not activating on the first cycle after replacement

After installation, the charge IC may default to trickle or standard rate on the first session while it reads the new BMS authentication data. This is normal behaviour on Realme's VOOC-adjacent charge protocol — the controller withholds high-current negotiation until it confirms cell identity. Disconnect the charger after the first full charge, power the phone fully off, then reconnect. Fast charging typically resumes from the second cycle onward.