Lenovo ZUK Z2 Pro Compatible Battery BL263 3.85V 3100mAh

Lenovo ZUK Z2 Pro — 3.85V Li-Polymer Replacement Battery (BL263)

This is a 3.85V, 3100mAh (11.94Wh) Li-Polymer replacement battery for the Lenovo ZUK Z2 Pro and its variants, including the Ultimate Edition, Ultimate Edition TD-LTE Dual SIM, and Exclusive Edition. It uses OEM part number BL263 and matches the original cell's dimensions at 75.00 × 59.60 × 4.40 mm. It fits directly into the ZUK Z2 Pro chassis without modification.

• ZUK Z2 Pro variant compatibility: The standard Z2 Pro, Ultimate Edition, TD-LTE Dual SIM, and Exclusive Edition all share the same battery bay dimensions and BL263 connector pinout. The BMS handshake is identical across these variants — same voltage rail, same NTC thermistor pin assignment.
• Bench tested on actual hardware: We ran this cell through charge-discharge cycles on a ZUK Z2 Pro unit and monitored BMS communication. The protection circuit engaged correctly at both low-voltage cutoff and thermal thresholds. Capacity output matched the rated 3100mAh within acceptable tolerance.
• Fuel gauge recalibration on first use: On first use after installation, disable fast charging for one complete discharge-charge cycle. The fuel gauge IC is calibrated to the old cell's discharge curve. Running one full cycle at standard current lets the coulomb counter reset its reference before high-current charging is applied to an uncalibrated cell.

Sudden shutdown at 20–30% on the ZUK Z2 Pro after a cell swap

The ZUK Z2 Pro's fuel gauge IC maps voltage to percentage using a curve built from the original cell's internal resistance profile. A new cell has lower impedance, so its voltage-to-capacity curve differs from what the IC expects. Under modem or screen load, the device sees a voltage reading that the IC interprets as critically low — even when charge remains. The fix is one full discharge to auto-shutdown followed by a full charge to 100% at standard charge rate. After that cycle, the IC recalibrates and shutdowns at low percentages stop.

USB fast charge not activating on the first cycle after replacement

After a battery swap, the charge IC on the ZUK Z2 Pro may not negotiate a fast-charge protocol on the first connection. The charge IC checks BMS state before stepping up current — a freshly installed cell with no charge history can cause the IC to default to standard 5V charging as a precaution. This is not a fault with the replacement cell or the charger. Complete one full charge at standard rate, then reconnect with your fast-charge adapter — the protocol negotiation completes normally from the second cycle onward.