Gresso Cruiser Replacement Battery 3.7V 820mAh Li-ion

Gresso Cruiser / Grand / Luxor / Regal — 3.7V Li-ion Replacement Battery

This is a 3.7V, 820mAh (3.03Wh) Li-ion replacement battery for the Gresso Cruiser, Grand, Luxor, and Regal mobile phones. It fits the same battery bay and connector shared across the Gresso luxury handset lineup. Install it when the original cell no longer holds charge through a normal day of calls and use.

• Cruiser, Grand, Luxor, and Regal compatibility: These four Gresso models share the same 54.26 × 33.67 × 4.23mm cell format, 3.7V nominal voltage rail, and connector pinout — so one replacement cell covers the full lineup without modification.
• Bench tested on actual hardware: We cycled this cell through full charge and discharge sequences and monitored BMS cutoff behavior at both ends of the voltage curve. The protection circuit tripped correctly at the low-voltage threshold, and charge acceptance was consistent across multiple cycles.
• Fuel gauge recalibration on first use: On first use after installation, disable fast charging and run one complete discharge-charge cycle. This gives the fuel gauge IC time to map the new cell's discharge curve before high-current charging is applied to an uncalibrated cell.

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

A new cell has a slightly different discharge curve than the original. The fuel gauge IC is still calibrated to the old cell, so it misreads the actual voltage state. When the modem or display pulls a current spike, the cell voltage drops below the BMS cutoff threshold before the OS knows it's that low. The phone shuts off even though the percentage display shows charge remaining. Run one full discharge to near-zero and a full charge to 100% — after that cycle, the coulomb counter aligns to the new cell and the shutdowns stop.

Phone won't power on after the replacement battery sat in storage

Li-ion cells self-discharge during storage. If the cell voltage dropped below approximately 2.5V per cell, the BMS enters lockout mode and blocks current flow to protect the cell from damage. The phone will show nothing when you press the power button — no charging animation, no response. Connect it to a wall charger, not a computer USB port, and leave it for 20–30 minutes without touching it. Most BMS circuits trickle-charge out of lockout at around 2.5–3.0V and then resume normal charging.