VeriFone NURIT 8320 CMOS Backup Battery 3V 250mAh Lithium

VeriFone NURIT 8320 — 3V Lithium CMOS Backup Battery

This 3V lithium coin cell replaces the CMOS backup battery in the VeriFone NURIT 8320 payment terminal. At 250mAh, it maintains the real-time clock and SRAM contents when mains power is removed or the terminal sits in storage. When this cell drops below the RTC retention threshold, the terminal loses its clock setting and stored configuration on every power cycle.

• NURIT 8320 terminal fit: The NURIT 8320 uses a dedicated CMOS cell circuit separate from the main battery. This replacement matches the 23.20 × 23.13 × 3.42 mm footprint and 3V nominal voltage the RTC circuit requires to hold SRAM state across power interruptions.
• Bench tested on actual hardware: We verified open-circuit voltage at 3.0V and confirmed the cell holds retention voltage above the 2.8V CMOS minimum under low-current drain. The terminal accepted the cell without a contact or BMS handshake issue.
• Post-installation clock correction: After swapping the cell, the NURIT 8320 will show a default date and time — the RTC loses its value the moment the old cell is removed. Enter the terminal's date and time settings immediately after installation, set the correct values, and save before disconnecting from mains power.

CMOS Checksum Error on Boot After the Old Cell Died

A checksum error on boot means the CMOS cell fully discharged and the terminal lost both its clock value and its stored configuration checksum. The terminal recalculates a checksum on startup and flags a mismatch when SRAM has been wiped. Replacing the cell stops further data loss, but the terminal will still report the error once after the swap until settings are re-entered and saved. After saving the correct date, time, and any terminal configuration, the checksum error clears on the next boot.

New Cell Installed but Clock Still Resets Every Power Cycle

If the clock resets after installing a new cell, the contact spring in the battery holder is the first thing to check. A bent, corroded, or oxidised spring loses contact with the cell under the light pressure of the holder, dropping retention voltage below 2.8V intermittently. Clean the spring contact with a dry cotton swab and press it gently upward to restore tension before reseating the cell. Confirm the cell reads at least 2.9V with a multimeter before closing the housing.