BenQ Joybook 2100 Replacement Battery 11.1V 6600mAh

BenQ Joybook 2100 / R22 — 11.1V Li-ion Replacement Battery (442677000001)

This is an 11.1V, 6600mAh (73.26Wh) Li-ion battery pack for the BenQ Joybook 2100 and R22 notebooks. It replaces the original cell when capacity has faded or the pack no longer holds a charge. Fits the same bay, uses the same connector, and works with the existing BMS handshake on both models.

• Joybook 2100 and R22 compatibility: Both models share the same 11.1V three-cell voltage rail, connector pinout, and BMS communication protocol — which is why a single pack covers the full range of OEM part numbers across the Joybook line, including BP-8389, BP-8889, and 442682800002.
• Bench tested on actual hardware: We cycled this pack through charge and discharge on the R22 platform. The BMS negotiated correctly on first connect, the BIOS recognised the pack, and cell voltage held steady across light and mid-load draw without triggering an early cutoff.
• First-cycle calibration on the Joybook: After installing, run one full discharge to hibernate-cutoff, then charge uninterrupted to 100%. This resets the BIOS battery learn cycle and clears the inaccurate health warning that shows up after every cell swap on the Joybook platform.

Why the Joybook BIOS reports poor battery health immediately after a swap

The Joybook's BIOS reads health data from EEPROM on the battery pack. The old pack wrote its degraded cycle count and capacity figures into that log before you removed it. When a new cell goes in, the BIOS compares its stored data against what it expects and flags a mismatch as poor health. This clears after one or two full charge-discharge calibration cycles, once the BIOS has written fresh baseline data to match the new cell's actual capacity.

Joybook shutting down at 20–30% charge shown on the gauge

This happens when the fuel gauge IC has not yet calibrated against the new cell's chemistry. The gauge IC stores reference curves from the old, degraded pack — so it misjudges the voltage cliff and triggers a shutdown well before the cell is actually empty. Run two full discharge-to-hibernate cycles followed by uninterrupted charges to 100%. After the second cycle, the gauge IC recalibrates its curve and the cutoff point drops back to the correct low-voltage threshold near 9.9V per pack.