About this replacement
Motorola XT2333 Series — 3.87V Li-Polymer Replacement Battery (PH50)
This is a 3.87V, 4850mAh lithium-polymer cell built to the PH50 specification for the Motorola XT2333 smartphone line. It fits the XT2333, XT2333-2, XT2333-3, and XT2333-4 variants. The pack slots into the same footprint as the original at 89.30 × 64.00 × 4.70mm.
- XT2333 variant compatibility: The XT2333-2, -3, and -4 share the same battery bay dimensions, connector pinout, and BMS handshake protocol as the base XT2333. Motorola kept the power architecture consistent across this sub-family, so one cell covers all variants without modification.
- Bench tested on actual hardware: We cycled this cell through charge and discharge on the XT2333 platform. The BMS accepted the pack without triggering a charge fault, and the fuel gauge IC completed initial calibration across a full discharge cycle without error codes.
- First-cycle fuel gauge calibration: On first use after installation, disable fast charging and run one complete discharge-charge cycle on standard charging. This gives the fuel gauge IC time to map the new cell's discharge curve before high-current charging pushes current into an uncalibrated cell.
Sudden shutdown at 20–30% on the XT2333 after a cell swap
A new lithium-polymer cell has a different internal impedance profile than the aged cell the phone's fuel gauge IC trained on. When the modem fires a high-current burst or the screen peaks at full brightness, the new cell's voltage drops sharply under load — crossing the hardware cutoff threshold even while the OS still reads 25%. The fuel gauge hasn't recalibrated yet, so the percentage shown is wrong. One full discharge-charge cycle on standard charging corrects the curve and eliminates the false cutoff.
USB-PD fast charge not accepted on the first cycle after replacement
The XT2333's charge controller negotiates fast charge only after it confirms the pack voltage and temperature are within a learned window. On a freshly installed cell, the controller defaults to standard 5V charging for the first cycle as a precaution — this is expected behaviour, not a fault. Once the fuel gauge IC completes one full calibration cycle, the fast charge handshake re-enables automatically. If fast charging still doesn't engage after a full cycle, confirm the charger outputs at least 9V/2A and the USB-C cable is rated for fast charge current.