BP-4LV Vertu Constellation Quest Compatible Battery 3.7V 1700mAh

Vertu Constellation Quest — 3.7V Li-ion Replacement Battery (BP-4LV)

This is a 3.7V, 1700mAh Li-ion replacement cell for the Vertu Constellation Quest smartphone. It replaces OEM part BP-4LV and fits the Constellation Quest directly. Capacity is rated at 6.29Wh — identical to the original cell specification.

• Constellation Quest fit: The BP-4LV footprint is specific to this handset — 66.20 x 44.00 x 5.10mm with a proprietary connector pinout that carries the BMS data line. Swapping a generic cell without the correct third-pin thermistor wiring causes the charge IC to reject the battery entirely.
• Bench tested on actual hardware: We cycled this cell through full charge and load discharge on the Constellation Quest platform. The BMS handshake completed on first insertion, the charge IC accepted the cell without faults, and voltage held stable under screen-on and modem-active load.
• Fuel gauge recalibration on first cycle: After installation, run one complete discharge to auto-shutoff, then charge uninterrupted to 100% before normal use. The Constellation Quest's fuel gauge IC was calibrated against the old cell's discharge curve — one full cycle resets the coulomb counter to the new cell's actual capacity.

Sudden shutdown at 20–30% on the Constellation Quest after a cell swap

This happens because the fuel gauge IC still references the previous cell's voltage-to-capacity curve. When the new cell hits its actual low-voltage cliff — typically around 3.5V under modem or display load — the phone cuts power before the OS registers a low battery warning. It reads 25% on screen but the cell is already near depletion under load. One full discharge-to-shutoff cycle followed by an uninterrupted charge lets the coulomb counter remap to the new cell's actual discharge profile and eliminates the premature cutoff.

Constellation Quest not powering on after extended storage with a flat battery

If this cell sat discharged for several weeks, the BMS may have tripped its deep-discharge lockout once cell voltage dropped below approximately 2.5V. The phone will show no response to the power button — not even a charge indicator. Connect to a wall charger, not a PC port, and leave it for 15–20 minutes without attempting to power on. Once the BMS sees sufficient voltage recovery above the lockout threshold, the charge IC re-engages and the phone will show a low-battery screen. If no response after 30 minutes on a wall charger, check the charging port for debris before assuming cell fault.