Lenovo Z6 Youth BL297 Replacement Battery 3.85V 3950mAh

Lenovo Z6 Youth / Z6 Lite — 3.85V Li-Polymer Replacement Battery (BL297)

This is a 3950mAh (15.21Wh) Li-Polymer cell replacing the OEM BL297 battery in the Lenovo Z6 Youth and Z6 Lite smartphones. It runs the same 3.85V nominal voltage as the original and connects via the stock flex connector with no modification. Use this when the original cell no longer holds charge, shuts down unexpectedly, or won't power the phone past a low percentage.

• Z6 Youth and Z6 Lite compatibility: Both handsets share the BL297 cell format, the same connector pinout, and the same charge IC on the board. One replacement cell covers both models without any wiring change.
• Bench tested on actual hardware: We ran the BL297 replacement through charge and discharge cycles on the bench. The BMS accepted the charge IC handshake correctly, and the cell held voltage without sag or cutoff at normal draw levels.
• First-cycle fast charge caution: After fitting this cell, disable fast charging for the first full discharge-to-charge cycle. The fuel gauge IC on the Z6 Youth calibrates its coulomb counter against the new cell's discharge curve. Running a high-current fast charge into an uncalibrated cell can skew percentage readings for the life of the battery.

Sudden shutdown at 20–30% on the Z6 Youth after cell replacement

This happens when the fuel gauge IC is still calibrated to the old cell's discharge curve. The new cell has a different voltage-to-capacity slope, so the IC underestimates remaining charge and triggers a low-voltage shutdown before the displayed percentage reaches zero. The modem and display together pull enough current to collapse the cell voltage below the protection threshold faster than the gauge predicts. Run one full discharge down to automatic shutoff, then charge uninterrupted to 100% — the coulomb counter resets against the new curve after that cycle.

USB fast charge not activating on the first cycle after fitting the BL297

On the first charge after a cell swap, the charge IC may stay in trickle-charge mode rather than stepping up to fast charge. This is a safety behaviour — the IC doesn't know the new cell's state of health yet and holds current low until it confirms the cell is stable. It is not a fault with the replacement battery. Charge once at standard speed to full, then disconnect and reconnect the charger — fast charge negotiation should engage normally from the second cycle onward.