Lenovo VIBE X2 BL231 Replacement Battery 3.8V 2230mAh

Lenovo VIBE X2 Series — 3.8V Li-Polymer Replacement Battery (BL231)

This is a 3.8V, 2230mAh Li-Polymer replacement battery for the Lenovo VIBE X2 smartphone. It fits the VIBE X2, VIBE X2-TO, VIBE X2-CU, and S90t. At 67.61 × 57.93 × 3.60mm, it matches the original cell footprint inside the chassis.

• VIBE X2 variant compatibility: The X2, X2-TO, X2-CU, and S90t share the same battery bay dimensions, connector pinout, and BMS handshake protocol — all accept the BL231 cell without modification.
• Bench tested on actual hardware: We ran this cell through full charge-discharge cycles on a VIBE X2 unit. The BMS accepted the cell on first connection, charge termination triggered correctly at 4.35V, and the protection circuit responded to load spikes without false cutoff.
• First-cycle fuel gauge reset: On first use after installation, disable fast charging and run one complete discharge-to-charge cycle. This lets the fuel gauge IC map the new cell's discharge curve before the charge IC starts pushing higher current into an uncalibrated cell.

Sudden shutdown at 20–30% on the VIBE X2 after a cell swap

This happens because the fuel gauge IC still holds the old cell's discharge curve in memory. The new cell's voltage drops faster under screen or modem load, so actual voltage hits the BMS cutoff threshold before the OS percentage reaches zero. The phone reads 25% but the cell is already at or below 3.4V under load. One full discharge to automatic shutdown, followed by an uninterrupted charge to 100%, resets the coulomb counter and eliminates the early cutoff.

Phone warm near the battery during the first few charging sessions

A new Li-Polymer cell has higher internal impedance than a broken-in cell. The charge IC dissipates more energy as heat during the first few cycles as impedance normalises. This is expected behaviour — not a fault with the cell or the charge circuit. If the device remains warm beyond the third full charge cycle, check that the back cover is seated correctly and not trapping heat against the cell.