Dell XPS 13 Replacement Battery 7.4V 5800mAh Y9N00

Dell XPS 13 / XPS 13-L321X / XPS 13-L322X — 7.4V Li-Polymer Replacement Battery (Y9N00)

This is a 7.4V, 5800mAh (42.92Wh) lithium-polymer battery for the Dell XPS 13 ultrabook range, including the L321X and L322X models. It replaces OEM part numbers Y9N00, 489XN, PKH18, WV7G0, 3H76R, NVR98, and several others. The cell fits directly into the XPS 13 chassis and connects to the existing BMS and charge controller without modification.

• XPS 13 L321X and L322X compatibility: Both chassis share the same 7.4V power rail, identical connector pinout, and the same BMS handshake protocol — which is why one cell covers both generations. The fuel gauge IC reads cell data over the SMBus, so the physical fit and electrical spec both need to match exactly.
• Bench tested on actual hardware: We ran this cell on an XPS 13-L321X unit. The BMS accepted the cell without fault codes, the charge controller cycled through bulk and taper phases cleanly, and the fuel gauge IC updated its state-of-charge readings within two charge cycles.
• Post-install calibration on XPS 13: 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 Dell XPS hardware.

BIOS reporting battery health as poor immediately after replacement

Dell's BIOS reads health data from the EEPROM embedded in the original cell. When a new cell goes in, the EEPROM data no longer matches the battery's actual charge history, so the BIOS flags it as degraded. This is a data mismatch, not a fault with the replacement cell. Run the battery learn cycle — one full discharge to hibernate threshold, then a full uninterrupted charge to 100%. After one or two cycles the BIOS recalibrates against the new cell and the health warning clears.

Laptop shuts down at 20–30% shown on the fuel gauge

This happens when the fuel gauge IC still holds calibration data from the old degraded cell. The percentage shown on screen no longer reflects the actual voltage curve of the new cell. Under full CPU and display load the real cell voltage drops faster than the gauge expects, and the system hits the low-voltage cutoff before the display reaches 0%. Force a full discharge to hibernate-cutoff, then charge to 100% without interruption — repeat this twice. The fuel gauge IC recalibrates its voltage-to-percentage mapping against the new cell and the premature shutdowns stop.