About this replacement
Motorola P30 Note / One Power — 3.8V Li-Polymer Replacement Battery (JK50)
This is a 3.8V, 4850mAh Li-Polymer replacement battery for the Motorola P30 Note, One Power, XT1942-1, XT1942-2, and compatible variants. It replaces the original JK50 cell when the factory battery no longer holds a useful charge or fails to power the device. Voltage and capacity match OEM spec — 18.43Wh total energy.
- XT1942 platform compatibility: The XT1942-1 and XT1942-2 variants share the same battery bay dimensions, connector pinout, and BMS handshake protocol as the P30 Note and One Power. One JK50 cell serves all these models because the charge IC and fuel gauge IC draw from the same voltage rail across the platform.
- Bench tested on actual hardware: We ran this cell through full charge-discharge cycles on XT1942 hardware. The BMS accepted the cell without rejection flags, thermal cutoff held within spec, and the charge IC completed cycles without early termination.
- First-cycle fast charging caution: After installation, disable fast charging and run one complete discharge-charge cycle at standard rate. This lets the fuel gauge IC recalibrate its coulomb counter against the new cell's discharge curve before high-current charging pushes current into an uncalibrated cell.
Sudden shutdown at 20–30% on the replacement JK50 cell
This happens when the fuel gauge IC is still calibrated to the old cell's discharge curve. The reported percentage doesn't match the actual cell voltage, so the phone hits the low-voltage cutoff before the OS sees it coming. The BMS trips protection at roughly 3.0V per cell — the OS just sees an instant shutdown. Fix it with one full discharge to auto-off, then a full uninterrupted charge to 100% without removing the cable early.
USB-PD fast charge not negotiating after a cell swap
On first connection after installation, the charge IC may not immediately negotiate fast charge protocols with a new, high-impedance cell. The phone charges slowly or shows standard charge only. This clears after the first full cycle — the charge IC re-profiles the cell impedance and renegotiates the protocol on the next plug-in. If fast charge still doesn't appear after two full cycles, check that the charger output is TurboPower-rated, not a generic 5V adapter.