Motorola KC40 Moto E6 Plus Compatible Battery 3.8V 2800mAh

Motorola Moto E6 Plus / E6S — 3.8V Li-Polymer Replacement Battery (KC40)

This is a 3.8V, 2800mAh (10.64Wh) lithium-polymer cell built to replace the KC40 battery in the Motorola Moto E6 Plus and E6S. It fits the XT2025-1 and XT2025-2 board revisions directly. When the original cell loses capacity or fails to hold a charge, this unit restores full phone function.

• XT2025-1 and XT2025-2 compatibility: Both board revisions use the same 3.8V power rail, KC40 connector pinout, and BMS handshake protocol — one cell covers both variants without any hardware modification.
• Bench tested on actual hardware: We ran this cell through full charge and discharge cycles on an XT2025-2 unit. The BMS accepted the new cell, charge termination triggered correctly at 4.35V, and the protection circuit cut off cleanly at the low-voltage threshold.
• Fuel gauge recalibration on first use: After fitting this cell, disable fast charging and run one complete discharge down to automatic shutdown, then charge fully to 100% on a standard 5V/1A charger. This gives the coulomb counter a clean reference cycle before fast charge pushes higher current into an uncalibrated cell.

Sudden shutdown at 20–30% on the Moto E6 Plus after a cell swap

The E6 Plus fuel gauge IC was calibrated to the discharge curve of the original KC40 cell. A new cell has a slightly different internal resistance profile, so the voltage reading the IC sees under modem or display load drops faster than the stored curve predicts. The phone interprets that voltage dip as a near-empty cell and triggers an emergency shutdown — even when the cell has remaining capacity. Running one full discharge-to-shutdown cycle followed by an uninterrupted charge to 100% resets the coulomb counter to the new cell's actual curve and stops false cutoffs.

USB-PD fast charge not engaging on the first cycle after replacement

On the first charge after fitting a new lithium-polymer cell, the charge IC on the XT2025 board sometimes withholds fast-charge handshake until it confirms the cell voltage is within the expected window — typically above 3.6V. If the replacement cell shipped at a low state of charge, plug into a standard 5V/1A charger and let it run until the phone shows at least 15% before attempting fast charge. Once the cell voltage clears 3.6V, the fast-charge protocol re-engages on the next plug-in cycle normally.