About this replacement
Oppo Realme V5 — 3.85V Li-Polymer Replacement Battery (BLP807)
This is a 3.85V, 4700mAh (18.1Wh) Li-Polymer battery carrying OEM part number BLP807. It fits the Realme V5 smartphone directly. The cell dimensions are 84.90 × 63.70 × 5.20mm, matching the original bay without modification.
- Realme V5 fit: The BLP807 uses the same connector pinout, flex cable routing, and BMS handshake protocol as the factory cell. The Realme V5 battery management system checks cell identification on boot — this replacement passes that check without triggering fault codes.
- Bench tested on actual hardware: We ran the BLP807 through full charge and discharge cycles on the Realme V5 platform. The BMS accepted the cell, charge termination fired correctly at 4.35V, and no thermal cutoff events occurred during the test sequence.
- 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 map the new cell's discharge curve before high-current charging pushes current into an uncalibrated cell — otherwise percentage readings will drift immediately.
Sudden shutdown at 20–30% on a replacement cell
This happens because the phone's coulomb counter is still calibrated to the old, degraded cell. A new cell has a steeper voltage drop under modem and screen load at that state-of-charge window. The fuel gauge misreads remaining capacity and the BMS cuts power before the cell is actually depleted. One full discharge to automatic shutdown, followed by an uninterrupted charge to 100%, resets the calibration reference and eliminates the premature cutoff.
VOOC fast charge not working on first cycle after a cell swap
Realme's VOOC protocol requires the charge IC to negotiate current limits with the BMS on the new cell before unlocking higher charge rates. On the first cycle, the charge IC often defaults to standard 5V/1A until it completes that handshake. This is normal behaviour — it is not a cable or adapter fault. Complete one full standard charge cycle and VOOC negotiation will initialise correctly on the next plug-in.