About this replacement
Vivo IQOO 7 / V2049A — 7.74V Li-Polymer Replacement Battery (B-P3)
This is a 1950mAh, 7.74V lithium-polymer cell that replaces the original B-P3 battery in the Vivo IQOO 7 (V2049A). It restores power to the processor, display, modem, and all onboard functions. Fit it when the original cell no longer holds a full charge, swells, or the phone shuts off unexpectedly under load.
- IQOO 7 and V2049A compatibility: Both model codes refer to the same hardware platform. They share the same battery bay dimensions (87.80 × 62.85 × 5.20mm), the same connector pinout, and the same BMS handshake protocol — so one cell covers both variants without modification.
- Bench tested on actual hardware: We ran this cell through charge and discharge cycles on the IQOO 7 platform. The BMS accepted the cell without triggering protection cutoff, and the charge IC negotiated normally after the first full cycle.
- First-cycle fast charge protocol: On first use after installation, disable fast charging and complete one full discharge-charge cycle at standard rate. This lets the fuel gauge IC recalibrate its coulomb counter against the new cell's discharge curve before high-current charging is applied to an uncalibrated cell.
Why the IQOO 7 reports wrong battery percentage after a cell swap
The fuel gauge IC builds its percentage readings from a learned discharge curve stored from the original cell. When a new cell goes in, that stored curve no longer matches actual cell chemistry or internal resistance. The IC keeps estimating against outdated data until it recalibrates. One complete discharge-to-shutdown followed by a full charge resets the coulomb counter and aligns the gauge to the new cell.
Sudden shutdown at 20–30% on the replacement cell
This happens when the modem or display pulls a high-current burst and the cell voltage drops below the BMS cutoff threshold — even though the reported percentage looks safe. On a freshly installed cell, the fuel gauge IC has not yet mapped the low-end voltage cliff for this specific cell's discharge curve. The phone reads 25% but the actual terminal voltage is already near 3.5V per cell under load. Run one complete cycle at standard charge rate first; the IC will then place the low-voltage cutoff point correctly and the shutdowns will stop.