PM16A Orange SPV M500 Replacement Battery 3.7V 2500mAh

Orange SPV M500 — 3.7V Li-Polymer Replacement Battery (PM16A)

This is a 3.7V, 2500mAh Li-Polymer battery that fits the Orange SPV M500 Windows Mobile smartphone. It replaces OEM part PM16A directly. If the original cell has degraded or holds no charge, this unit restores the phone to working condition.

• SPV M500 cell match: The M500 runs a single-cell Li-Polymer configuration at 3.7V nominal. The BMS on this device uses a fixed charge termination voltage of 4.2V. Any replacement cell must match that threshold — a mismatch here causes the charge IC to cut off early or overrun the cell.
• Bench tested on actual hardware: We ran this cell through a full charge-discharge cycle on the M500 platform. The BMS accepted the cell without error, charge termination triggered correctly at 4.2V, and the fuel gauge IC registered a full-state reading after one complete cycle.
• Fuel gauge recalibration on first use: On first installation, disable any battery saver shortcuts and run one uninterrupted discharge down to the auto-shutdown point, then charge fully without interruption. The M500's fuel gauge IC maps its capacity model to the old cell — one full cycle forces it to relearn against the new discharge curve.

Why the SPV M500 reports wrong battery percentage after a cell swap

The M500 uses a fuel gauge IC that builds a discharge curve model from historical cell data. When a new cell goes in, that stored model no longer matches the actual cell chemistry. The IC reads voltage and translates it to a percentage using the old curve — so the number on screen can be 20–30% off in either direction. One full discharge-charge cycle lets the IC rebuild its model against the new cell. After that cycle, percentage readings stabilise.

Sudden shutdown at 20–30% remaining on the SPV M500

This happens when the cell voltage drops below the BMS cutoff threshold under load before the fuel gauge has recalibrated. The modem radio and screen together pull enough current to cause a sharp voltage sag — the cell can't sustain the load voltage, and the BMS trips the circuit even though the gauge still shows charge remaining. It's not a faulty battery; it's the fuel gauge reading from a mismatched curve. Run one complete discharge to auto-shutdown and charge back to 4.2V — the cutoff events should stop after that cycle.