Motorola KP50 Moto One Zoom Replacement Battery 3.85V 3900mAh

Motorola Moto One Zoom — 3.85V Li-Polymer Replacement Battery (KP50)

The KP50 is a 3900mAh Li-Polymer cell at 3.85V, built as a direct replacement for the Motorola Moto One Zoom and its global variants including the XT2010-1. If your phone no longer holds charge or shuts down unexpectedly before the battery indicator reaches zero, the original cell has degraded and needs replacing.

• Moto One Zoom and XT2010 variants: All listed variants — Moto One Zoom, Moto One Zoom Global, and XT2010-1 — share the same battery bay dimensions, connector pinout, and BMS handshake protocol. One cell covers the full lineup without modification.
• Bench tested on actual hardware: We ran this cell through full charge and discharge cycles on the Moto One Zoom platform. The BMS accepted the KP50 without triggering a charge fault, and the fuel gauge IC initialised correctly after one complete cycle.
• First cycle after installation: Disable fast charging for the first complete discharge-charge cycle. This lets the fuel gauge IC recalibrate its coulomb counter against the new cell's actual discharge curve before high-current charging is applied to an uncalibrated cell.

Sudden shutdown at 20–30% on the Moto One Zoom after a cell swap

This happens because the fuel gauge IC is still reading from the old cell's discharge curve stored in memory. The new cell hits a voltage cliff under modem or display load at a state-of-charge the gauge thinks is safe. The phone's processor sees the rail drop below its minimum threshold and cuts power before the percentage reaches zero. One full discharge-charge cycle without fast charging forces the coulomb counter to remap against the new cell's actual voltage curve and eliminates the premature cutoff.

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

On the first charge after installing a new cell, the charge IC may not negotiate fast charge protocols until it has completed at least one slow trickle-to-full cycle. The BMS uses the initial cycle to set internal resistance baselines and verify cell health before allowing high-current input. Charging at standard speed for the first full cycle is the fix. After that cycle completes, fast charging will engage normally on subsequent connections.