Telstra F500 Li3708T42P3h453756 Compatible Battery 3.7V 830mAh

Telstra F500 / F188 Series — 3.7V Li-ion Replacement Battery (Li3708T42P3h453756)

This is a 3.7V 830mAh Li-ion cell for the Telstra F500, F188, F230, F233, and compatible models. It fits the same physical footprint as the original and uses the OEM connector pinout. Capacity is rated at 830mAh (3.07Wh) — matched to the product data, not inflated.

• F500 / F188 / F230 / F233 compatibility: These models share the same 3.7V single-cell architecture, connector orientation, and BMS handshake protocol — which is why one cell covers the full range. The fuel gauge IC on each device reads the same charge curve.
• Bench tested on actual hardware: We cycled this cell on the F500 platform through a full discharge-charge sequence. The BMS accepted the new cell without a fault flag, and the charge IC held current within spec through the CV phase.
• Fuel gauge recalibration on first use: On first installation, disable fast charging and run one complete discharge-charge cycle at standard rate. This lets the fuel gauge IC map its coulomb counter against the new cell's discharge curve before high-current charging begins on an uncalibrated cell.

Why the F500 reports wrong battery percentage after a cell swap

The F500's fuel gauge IC stores a learned discharge curve from the old cell. When a new cell goes in, the IC is still running that old calibration — so the percentage it displays reflects the previous cell's impedance profile, not the new one. This causes the phone to report inaccurate state-of-charge, often showing full charge well before the cell is actually topped up. One complete discharge cycle down to automatic cutoff, followed by a full standard-rate charge, forces the IC to rewrite its internal model against the new cell.

Sudden shutdown at 20–30% on the replacement cell

This happens when the modem or screen draws a short high-current spike and the cell voltage drops below the BMS cutoff threshold — even though the fuel gauge still shows charge remaining. It is a voltage-cliff issue, not a capacity problem. The cell's internal resistance causes a brief voltage sag under load that the BMS reads as a low-cell fault and cuts power. Run two full discharge-charge cycles to let the fuel gauge recalibrate, and confirm resting cell voltage sits above 3.6V after a full charge before calling the cell faulty.