Olympia Luna ICP423443 Replacement Battery 3.7V 700mAh

Olympia Luna — 3.7V Li-ion Replacement Battery (ICP423443)

This is a 3.7V, 700mAh (2.59Wh) Li-ion replacement battery for the Olympia Luna smartphone. It replaces the OEM cell ICP423443 when the original degrades, fails to hold charge, or stops powering the device entirely. Dimensions are 47.10 × 36.75 × 4.60mm — verify your original cell matches before installing.

• Olympia Luna fit: The Luna uses a compact single-cell Li-ion pack at 3.7V nominal. This cell matches the original ICP423443 footprint and voltage rail, so the charge IC and fuel gauge IC see a recognised cell profile on first boot.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on the bench. The BMS accepted charge input without rejection and held voltage above the low-battery cutoff threshold through a full drain cycle.
• 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 Luna reports wrong battery percentage after a cell swap

The fuel gauge IC on the Luna stores a discharge curve from the previous cell. When a new cell goes in, that stored curve no longer matches the actual voltage-to-capacity relationship of the replacement. The OS reads the old map and reports inaccurate percentages — often inflated early in the charge cycle and suddenly low as the cell approaches actual cutoff. One full discharge-to-shutdown followed by an uninterrupted charge to 100% lets the coulomb counter reset against the new cell and restores accurate reporting.

Sudden shutdown at 20–30% on the replacement cell

This happens when the cell voltage drops sharply under load — screen backlight, modem transmit, or GPS all pull current spikes that can drag a partially discharged Li-ion cell below the BMS cutoff threshold of around 3.0V momentarily. The phone shuts down even though the displayed percentage suggests charge remains. After the BMS trips, leave the phone on charge for at least 15 minutes before powering on — this brings the resting cell voltage back above 3.4V and clears the BMS lockout before the OS boots.