NGM Vorwarts Replacement Battery 3.7V 1350mAh Li-ion

NGM Vorwarts — 3.7V Li-ion Replacement Battery

This is a 3.7V, 1350mAh Li-ion cell for the NGM Vorwarts smartphone. It fits directly into the handset and restores full power capacity when the original cell has degraded through normal charge cycling. No OEM part number exists for this battery — fit is confirmed by model and physical dimensions.

• NGM Vorwarts platform fit: The Vorwarts uses a compact 3.7V single-cell architecture with a slim form factor. This cell matches the 62.01 × 52.90 × 4.41 mm bay dimensions and the connector orientation required by the handset's charge IC.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on compatible hardware and monitored BMS cutoff behaviour at both ends of the voltage range. The protection circuit held the low-voltage cutoff correctly and did not trip under normal smartphone load profiles.
• Fuel gauge recalibration after swap: On first use after fitting this cell, run one complete discharge to automatic shutdown followed by a full uninterrupted charge. This lets the Vorwarts fuel gauge IC map its coulomb counter against the new cell's actual discharge curve before normal use.

Why the NGM Vorwarts reports wrong battery percentage after a cell swap

The Vorwarts stores a discharge curve in its fuel gauge IC calibrated to the original cell. When a new cell goes in, the IC has no reference data for the replacement's internal resistance or capacity profile. It continues estimating state-of-charge against the old curve, which causes percentage readings to drift or jump. One full discharge-charge cycle forces the IC to rebuild its calibration table against the new cell, after which percentage readings stabilise.

Sudden shutdown at 20–30% on the NGM Vorwarts

This happens when the cell voltage drops sharply under load — typically when the modem fires at full transmit power or the screen brightness peaks. The fuel gauge reads 20–30% by coulomb count, but the cell cannot sustain the voltage rail under that current draw. The BMS interprets the voltage sag as a low-cell event and cuts output. If this occurs after fitting a new cell, run the recalibration cycle first; if it persists, check that the battery connector is fully seated, as a partial connection raises contact resistance and worsens voltage sag.