About this replacement
Samsung Q318 Series — 11.1V Li-ion Replacement Battery (AA-PB9NC6B)
This is an 11.1V, 6600mAh (73.26Wh) Li-ion battery for the Samsung Q318 notebook series, including the Q318-DSOE, Q318-DS0H, and Q318-DS02. It replaces a degraded or failed original pack when the laptop can no longer sustain charge away from the mains. Cross-compatible OEM part numbers include AA-PB9NS6B, AA-PB9NC5B, AA-PL9NC6W, and AA-PB9MC6B among others.
- Q318 series compatibility: These Q318 variants share the same 11.1V three-cell voltage rail, identical connector pinout, and the same BMS handshake protocol — which is why a single replacement pack covers the full model range without modification.
- Bench tested on actual hardware: We ran this pack through charge and discharge cycles on Q318 hardware. The BMS engaged thermal protection correctly, cell balancing held within spec across all three cell groups, and the pack communicated accurate state-of-charge data back to the system.
- Post-install calibration on the Q318: After fitting this pack, run one full discharge until the laptop hibernates on low battery, then charge uninterrupted to 100% without interruption. This resets the BIOS battery learn cycle and clears the inaccurate health warning that shows up after every cell swap on this platform.
BIOS reporting battery health as poor immediately after fitting a new pack
Samsung's Q318 BIOS reads health data from EEPROM stored in the old battery pack — it does not automatically reset when a new pack is installed. The system compares current cell data against the previous pack's wear history, so a new pack can trigger a false "Replace Battery" or "Poor Health" flag straight out of the box. Running one complete discharge-to-hibernate followed by an uninterrupted charge to 100% forces the BIOS to rewrite its battery learn table against the new cell's actual chemistry. After two or three full cycles, the health indicator should update to reflect the new pack accurately.
Q318 shutting down abruptly at 20–30% charge shown on screen
This is a voltage-cliff failure, not a capacity problem. When the CPU and display pull peak load simultaneously, the cell voltage under load drops below the BMS cutoff threshold even though the fuel gauge still reads 20–30% remaining. The fuel gauge IC has not yet calibrated its discharge curve against the new cell, so it overestimates remaining capacity at the high-draw end of the cycle. Run two or three full discharge-to-hibernate cycles and the fuel gauge will recalibrate its endpoint — the shutdowns stop once the IC maps the actual voltage curve of the new cells down to the 3.0V per cell cutoff floor.