Clevo W860BAT-3 Replacement Battery 11.1V 3800mAh

Clevo W860CU Series — 11.1V Li-Polymer Replacement Battery (W860BAT-3)

This is an 11.1V, 3800mAh (42.18Wh) lithium-polymer replacement battery for the Clevo W860CU mobile workstation and its variants, including the W860CU-3D, W860CU-PS1, and 8690-3D. It replaces OEM part numbers W860BAT-3, 6-87-W87S-421A, and 6-87-W870S-421A. If the original cell no longer holds a charge, this is the direct cell swap.

• W860CU variant compatibility: The W860CU, W860CU-3D, W860CU-PS1, and 8690-3D all share the same battery bay form factor, three-cell 11.1V voltage rail, and BMS connector pinout — which is why a single cell covers the full group.
• Bench tested on actual hardware: We ran this cell through charge and discharge cycles on the W860CU platform. The BMS handshake completed correctly, charge current ramped normally to full CV phase, and the cell balanced across all three groups without fault flags.
• Post-install conditioning for W860CU: After fitting this cell, run one full discharge to the hibernate cutoff, then charge uninterrupted to 100%. This resets the BIOS battery learn cycle and clears the inaccurate health warning that appears after every cell swap on this platform.

BIOS reporting poor battery health after fitting a new cell

The W860CU BIOS stores battery health data in EEPROM on the old cell's embedded controller. When a new cell goes in, the BIOS reads stale EEPROM values and flags the battery as degraded — even though the new cell is at full capacity. This is not a fault with the replacement. One full discharge-to-hibernate followed by an uninterrupted charge to 100% triggers the BIOS learn cycle and overwrites the cached health data. After two or three cycles, the reported health figure will stabilise to reflect the new cell's actual state.

Laptop shutting down at 20–30% charge shown on screen

This happens when the fuel gauge IC on the W860CU has not yet calibrated against the new cell's chemistry. The gauge is still mapping voltage curves from the old, degraded cell, so it calls empty too early. Under full CPU and display load, the cell hits a voltage point the uncalibrated gauge reads as critically low and cuts power. Run two complete discharge-to-hibernate and charge-to-100% cycles without interruption. After calibration, the shutdown threshold aligns correctly and the gauge should hold steady past 15% under load.