Virgin Mobile Venture VM2045 Replacement Battery 3.7V 1300mAh

Virgin Mobile Venture VM2045 — 3.7V Li-ion Replacement Battery

This is a 3.7V, 1300mAh Li-ion replacement battery for the Virgin Mobile Venture VM2045 smartphone. It fits directly into the battery bay and connects to the same three-contact strip used by the original cell. Voltage and capacity match the factory specification exactly.

• VM2045 fit: The Venture VM2045 uses a slim 64.30 × 49.50 × 4.50mm cell with a three-pin contact layout. This replacement matches those physical dimensions and the voltage rail the phone's charge IC expects. A mismatched voltage would prevent the device from booting past the splash screen.
• Bench tested on actual hardware: We cycled this cell through a full charge-discharge sequence and confirmed the BMS handshake completes without triggering a charge fault. The protection circuit held cutoff at the correct low-voltage threshold — no false trips on a normal draw cycle.
• Fuel gauge recalibration on first install: After fitting this cell, disable fast charging and run one complete discharge-to-charge cycle before normal use. The VM2045's fuel gauge IC is calibrated to the old cell's discharge curve — one full cycle lets it remap to the new cell before high-current charging pushes current into an uncalibrated state.

Why the VM2045 reports wrong battery percentage after a cell swap

The Venture VM2045 uses a fuel gauge IC that tracks charge state against a stored discharge curve from the original cell. When a new cell goes in, that stored curve no longer matches the actual chemistry. The phone reads the new cell's voltage and maps it to the old curve, which shifts the percentage display up or down by as much as 15–20%. One full discharge-charge cycle forces the IC to relearn the new cell's voltage-to-capacity relationship and corrects the readout.

Sudden shutdown at 20–30% charge showing on screen

This is a voltage cliff failure — the cell cannot hold voltage above the BMS cutoff threshold when the modem or screen draws a spike of current. The percentage shown is based on open-circuit voltage, but under load the cell voltage collapses past 3.0V and the protection circuit cuts power instantly. It is common in aged cells where internal resistance has climbed, and it can also appear in a new cell that has not completed a calibration cycle. Run one full discharge down to automatic shutdown, then charge uninterrupted to 100% to give the fuel gauge IC an accurate baseline.