Samsung NP350U2A Replacement Battery 7.4V 6350mAh AA-PBZN6PN

Samsung NP350U2A Series — 7.4V Li-Polymer Replacement Battery (AA-PBZN6PN)

This is a 7.4V, 6350mAh (46.99Wh) Li-Polymer replacement battery for the Samsung Series 5 ultrabook. It fits the NP350U2A, NP350U2Y, and NP350U2B. It replaces OEM parts AA-PBZN6PN and BA43-00315A directly.

• NP350U2A, NP350U2Y, NP350U2B compatibility: All three models run the same 7.4V two-cell Li-Polymer configuration, share the same connector pinout, and use the same BMS communication protocol over the SMBus line — so one cell fits all three without modification.
• Bench tested on actual hardware: We ran this cell through charge and discharge cycles on the NP350U2A platform. The BMS handshake completed cleanly, the fuel gauge IC registered the new cell, and the charge controller reached 8.40V terminal voltage without fault codes.
• Post-install calibration on the NP350U2A: After fitting this cell, 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 appears after every cell swap on this platform.

BIOS reporting battery health as poor after replacement on the NP350U2A

The NP350U2A stores battery health data in EEPROM on the old cell. When a new cell goes in, the BIOS reads stale EEPROM values that don't match the new chemistry — so it flags a health warning immediately. This is not a fault with the replacement cell. Running one complete discharge-to-hibernate followed by a full uninterrupted charge gives the BIOS enough cycle data to overwrite those stale values. After two to three full cycles, the health indicator normalises and the warning clears.

NP350U2A shutting down at 20–30% charge shown on screen

This symptom points to a voltage cliff in the old cell — not a calibration error. Under combined CPU and display load, a degraded cell drops below the BMS cutoff voltage before the fuel gauge reaches 0%, so the system shuts down while showing apparent charge remaining. A new cell holds the voltage above cutoff under load. If this symptom appears on a new cell, the fuel gauge IC has not yet calibrated against the new chemistry — run two full discharge-to-hibernate cycles and verify the pack voltage sits above 7.0V under load before dismissing the unit.