Telstra 4GX Buzz Compatible Battery 3.8V 2300mAh Li-ion

Telstra 4GX Buzz — 3.8V Li-ion Replacement Battery

This is a 3.8V, 2300mAh lithium-ion battery for the Telstra 4GX Buzz Android smartphone. It fits directly into the original battery bay and restores power capacity lost through cell degradation. Dimensions are 66.60 × 50.20 × 5.30mm — confirm your original cell matches before installing.

• 4GX Buzz platform fit: The 4GX Buzz runs a standard 3.8V nominal rail with a charge ceiling of 4.35V. This cell matches that rail. The phone's charge IC communicates directly with the cell — no adapter or wiring change is needed.
• Bench tested on actual hardware: We cycled this cell through a full charge and discharge on the 4GX Buzz platform. The BMS accepted the cell without fault flags, and the charge IC stepped through its taper phase correctly at end-of-charge.
• First-cycle fuel gauge recalibration: After installation, disable fast charging in the phone's settings and run one complete discharge down to automatic shutdown, then charge uninterrupted to 100%. This lets the fuel gauge IC map the new cell's discharge curve before high-current charging begins.

Why the 4GX Buzz shuts down suddenly at 20–30% after a battery swap

The 4GX Buzz uses a coulomb-counter fuel gauge that was calibrated to the discharge curve of the original — usually degraded — cell. When a new cell with a steeper voltage cliff is installed, the gauge's stored curve no longer matches the actual cell behaviour. Under modem or screen load, voltage drops faster than predicted, and the phone triggers a protective shutdown before the gauge reaches 0%. One full discharge-to-shutdown followed by a complete uninterrupted charge resets the calibration reference and stops the early cutoff.

Battery percentage jumping erratically after installation

Erratic percentage readings — jumping from 45% to 62% or dropping 15% in seconds — point to the fuel gauge IC recalibrating against an unfamiliar cell impedance profile. The gauge interpolates state-of-charge from voltage and current data, and a new cell's internal resistance differs from the worn original. The fix is straightforward: let the phone discharge fully to auto-shutdown, then charge without interruption to 100%. After that single anchored cycle, the gauge locks onto the new cell's curve and percentage readings stabilise.