Vertu Constellation Quest Replacement Battery 3.7V 1500mAh

Vertu Constellation Quest — 3.7V Li-ion Replacement Battery

This is a 3.7V, 1500mAh Li-ion cell built to replace the original battery in the Vertu Constellation Quest. The Constellation Quest is a luxury touchscreen smartphone, and this battery restores power to aging or degraded units. Fit dimensions are 65.80 × 43.90 × 5.10mm — confirm these against your original cell before installing.

• Constellation Quest platform fit: The Constellation Quest uses a single fixed-format Li-ion cell connected directly to an internal charge IC. The connector pinout, cell dimensions, and BMS voltage thresholds must match the original exactly — this cell meets those specifications.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on compatible hardware. The BMS accepted the full 4.2V charge ceiling and held a stable output voltage across screen-on and modem-active load states.
• Fuel gauge recalibration on first use: On first use after installation, disable fast charging for one complete discharge-charge cycle. This lets the fuel gauge IC recalibrate against the new cell's discharge curve before high-current charging is applied to an uncalibrated cell.

Why the Constellation Quest reports wrong battery percentage after a cell swap

The Constellation Quest uses a fuel gauge IC that builds its charge estimate from the old cell's discharge curve stored in memory. When a new cell goes in, that stored curve no longer matches the new cell's actual voltage-to-capacity relationship. The result is a percentage readout that drifts or reads high early and then drops suddenly. One full discharge-charge cycle — down to automatic shutdown, then a complete charge to 100% — forces the fuel gauge IC to relearn the curve against the new cell.

Sudden shutdown at 20–30% on the replacement cell

This happens when the cell voltage drops below the phone's minimum operating threshold under a high-draw load — typically the modem transmitting or the display at full brightness. The fuel gauge still shows 20–30% because it's reading average voltage, not instantaneous voltage under load. The cell cannot sustain voltage under that spike, so the phone shuts down as a protective measure. After a full calibration cycle, the fuel gauge maps this voltage cliff correctly and the shutdown point drops to the expected near-zero level.