BASE Lutea 3 Replacement Battery 3.7V 1650mAh Li-ion

BASE Lutea 3 — 3.7V Li-ion Replacement Battery

This is a 3.7V, 1650mAh Li-ion replacement battery for the BASE Lutea 3 (also listed as Lutea III). It fits directly into the existing battery compartment and restores power to the device when the original cell has degraded or failed. No OEM part number is published for this battery.

• Lutea 3 and Lutea III compatibility: Both names refer to the same handset. The battery compartment, connector orientation, and cell dimensions (57.10 × 50.98 × 5.90mm) are identical across both variants, so one cell covers both.
• Bench tested on actual hardware: We ran the cell through a full charge and discharge cycle on the bench. The BMS held protection thresholds correctly — no false overcurrent trips, and the charge IC accepted the cell without flagging an authentication error.
• Fuel gauge recalibration on first cycle: After installation, disable fast charging and run one complete discharge-charge cycle at standard rate. The fuel gauge IC on the Lutea 3 calibrates its coulomb counter against the cell's discharge curve — skipping this step with a new high-impedance cell leads to inaccurate percentage readings from the first use.

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

A new cell has a slightly different discharge curve than the original. The fuel gauge IC still references the old curve, so it reads 25% while the actual cell voltage has already dropped close to the BMS cutoff threshold. When the modem fires up or the screen peaks brightness, the load spike pulls the voltage below 3.0V and the BMS cuts power instantly. One full discharge-to-charge cycle at standard rate re-anchors the coulomb counter to the new cell's curve and eliminates these cutoffs.

Phone not powering on after the replacement battery sat in storage

Li-ion cells self-discharge in storage. If the cell voltage drops below approximately 2.5V, the BMS enters lockout mode and blocks normal charging to prevent damage. The phone will show no sign of life — no boot, no charging indicator. To recover, connect to a wall charger rather than a PC USB port, which delivers enough current to trigger the BMS trickle-charge recovery mode. Leave it on charge for 20–30 minutes before attempting to power on; the BMS needs to see the cell voltage climb above 3.0V before it releases the lockout.