BASE Lutea 3 Replacement Battery 3.7V 1950mAh Li-ion

BASE Lutea 3 — 3.7V Li-ion Replacement Battery

This 3.7V, 1950mAh Li-ion cell is a direct replacement for the BASE Lutea 3 (also sold as the Lutea III). It fits the original battery bay without modification and connects to the phone's power management IC through the same flex connector. Capacity is 1950mAh — use that figure when comparing against your worn original.

• Lutea 3 and Lutea III compatibility: Both names refer to the same hardware platform. The battery bay dimensions, connector pinout, and BMS handshake voltage are identical across the two marketed variants — one replacement cell covers both.
• Bench tested on actual hardware: We cycled this cell through charge and discharge under the Lutea 3's power management IC. The BMS accepted the cell without fault flags, and the charge IC stepped through CC/CV stages cleanly on repeated cycles.
• 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 its coulomb counter against the new cell's actual discharge curve before high-current charging is applied to an uncalibrated cell.

Sudden shutdown at 20–30% on the Lutea 3 after a cell swap

The Lutea 3's fuel gauge IC was calibrated to the discharge curve of the original cell — not the replacement. When the new cell's voltage drops steeply under modem or screen load, the IC hasn't yet mapped that curve and misreads remaining charge. The phone's low-voltage protection trips before the percentage display catches up, causing an abrupt shutdown that looks like a dead battery. One full discharge-charge cycle without fast charging lets the coulomb counter reset against the new cell's actual curve. After that cycle, shutdowns at 20–30% typically stop.

BASE Lutea 3 won't power on after sitting in storage

Li-ion cells self-discharge during storage. If the Lutea 3 sat unused for several months — before or after the battery swap — the cell voltage may have dropped below the BMS lockout threshold of approximately 2.5V. At that point the BMS disconnects the cell to prevent damage, and the phone shows no response to the power button. Connect the phone to a wall charger rather than a PC port and leave it for 20–30 minutes before attempting to power on — a wall charger delivers enough current to nudge the BMS out of lockout. If the charge LED does not activate within that window, try a second charger to rule out the cable before concluding the cell is unrecoverable.