Vivo BA90 V2444A Replacement Battery 3.91V 6350mAh

Vivo V2444A / Y300I — 3.91V Li-Polymer Replacement Battery (BA90)

The BA90 is a 3.91V, 6350mAh (24.83Wh) lithium-polymer cell that fits the Vivo V2444A and Y300I smartphones. It replaces the original battery when the existing cell can no longer hold a stable charge or shuts the phone down unexpectedly. Voltage and connector pinout match the OEM spec exactly.

• V2444A and Y300I platform fit: Both devices share the same battery bay dimensions, 3.91V nominal rail, and BA90 connector layout. The BMS handshake uses the same communication line, so the charge IC accepts this cell without triggering a rejection fault.
• Bench tested on actual hardware: We cycled this cell through full charge and discharge on the V2444A platform. The BMS reported correct cell recognition on first connect, and the charge IC completed a full CC/CV charge cycle without flagging an error or dropping to trickle-charge prematurely.
• 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 recalibrate against the new cell's discharge curve before high-current charging pushes current into an uncalibrated cell — reducing erratic percentage readings in the first few days.

Sudden shutdown at 20–30% on the BA90 replacement cell

This happens because the fuel gauge IC on the V2444A is still calibrated to the discharge curve of the old, degraded cell. When the new BA90 draws current under modem or display load, the IC reads the voltage drop incorrectly and triggers a low-battery shutdown well above the actual cutoff. The fix is a full drain-to-shutdown followed by an uninterrupted charge to 100% — repeat this once or twice. After two full cycles, the coulomb counter resets its reference and the percentage readout stabilises.

USB fast charge not initiating after battery replacement

On the first charge cycle after swapping the BA90 in, the charge IC may default to standard 5V/1A input and refuse to negotiate the Vivo fast-charge protocol. This occurs because the BMS on a fresh cell presents a slightly higher impedance than a broken-in cell, and some charge controllers interpret this as a fault condition. Plug in the cable, let the phone charge fully at standard rate without interruption, then unplug and replug — most units accept the fast-charge handshake on the second connection. If it still fails after the first full cycle, check that the charge port and cable are clean and undamaged, as the protocol negotiation runs over the same data pins.