Vivo iQOO 11s BA01 Replacement Battery 7.78V 2400mAh

Vivo iQOO 11s Series — 7.78V Li-Polymer Replacement Battery (BA01)

This 7.78V, 2400mAh Li-Polymer cell replaces the BA01 battery in the Vivo iQOO 11s, iQOO 11S 5G, and V2304A. It targets phones where the original cell has degraded and no longer holds adequate charge. Voltage and capacity match the OEM specification exactly.

• iQOO 11s / V2304A compatibility: The iQOO 11s and V2304A share the same dual-cell Li-Polymer stack, voltage rail, and BMS connector pinout. Any cell going into this platform must match the 7.78V nominal — two 3.89V cells wired in series. This BA01 replacement meets that requirement without hardware modification.
• Bench tested on actual hardware: We cycled this cell on an iQOO 11S 5G unit and confirmed the BMS accepted the handshake without fault codes. The charge IC stepped through trickle, CC, and CV phases cleanly, and the fuel gauge IC began tracking state-of-charge from the first cycle.
• 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 build an accurate discharge curve against the new cell before high-current fast charging pushes charge into an uncalibrated state-of-charge register.

Why the iQOO 11s reports wrong battery percentage after a cell swap

The iQOO 11s uses a coulomb counter inside the fuel gauge IC to track remaining capacity. That counter is calibrated to the discharge curve of the original cell. When a new cell goes in, the counter still references the old curve, so the percentage readout drifts — often reading 10–15% higher than actual state-of-charge. One full discharge-charge cycle without interruption resets the learned curve. After that cycle, the percentage tracking aligns to the new cell's actual behaviour.

Sudden shutdown at 20–30% on the replacement cell

This happens when the cell voltage drops below the BMS protection threshold under load — typically when the modem, display, and CPU draw simultaneously. The fuel gauge IC still shows 20–30%, but the cell can no longer sustain voltage above the BMS cutoff point under that combined current draw. This is a calibration gap, not a faulty cell. Run two full discharge cycles and check that the phone does not shut off above 3.6V per cell — if it does, the BMS has triggered a low-voltage latch that clears only after a charge to 4.35V per cell.