Dell Latitude 9440 2-in-1 Replacement Battery 11.55V 5150mAh

Dell Latitude 9440 / 9450 2-in-1 — 11.55V Li-Polymer Replacement Battery (GT6TK / K2CPY)

This is an 11.55V Li-Polymer replacement battery rated at 5150mAh (59.48Wh), built to fit the Dell Latitude 9440 2-in-1 and Latitude 9450 2-in-1. It replaces OEM part numbers GT6TK and K2CPY directly. Install it when the original cell has lost capacity, stopped charging, or is triggering low-battery warnings earlier than expected.

• Latitude 9440 and 9450 2-in-1 compatibility: Both models share the same 11.55V battery rail, physical connector, and BMS handshake protocol. The same cell fits both because Dell used a common power platform across this generation of convertible Latitude hardware.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on the Latitude 9440 platform. The BMS communicated correctly with the Dell EC, reported accurate state-of-charge data, and held voltage within spec across the full discharge curve.
• Post-install calibration — Latitude 9440 / 9450: After fitting this battery, run the laptop down to hibernate-cutoff on battery power only, 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 these models.

Why the Latitude 9440 shuts down at 20–30% after a battery swap

The Dell Latitude 9440 uses a fuel gauge IC that builds a discharge model based on the old cell's characteristics. When a new cell is installed, that model is wrong — the IC predicts a voltage cliff earlier than the new cell actually hits one. This causes the laptop to call for shutdown at 20–30% displayed charge, even though usable capacity remains. Running two to three full discharge-and-charge cycles forces the fuel gauge to recalibrate against the new cell's actual voltage curve. After calibration, reported percentage and real capacity align correctly.

BIOS reporting battery health as "poor" or "replace soon" immediately after install

This warning appears because the Dell BIOS reads health data stored in the old battery's EEPROM and compares it against expected parameters for a new cell — the mismatch triggers the alert. The new cell has no degradation data yet, so the BIOS flags the absence as a fault. Run the battery learn cycle: discharge fully to hibernate, then charge to 100% without interruption. On the next boot, the BIOS re-evaluates and the warning clears once it reads the updated state-of-charge data from the new cell.