Medion MD97690 CMOS Replacement Battery 3V 200mAh

Medion MD97690 / Akoya E1312 — 3V Lithium CMOS Backup Battery

This is a 3V 200mAh lithium coin cell that replaces the CMOS backup battery on the Medion MD97690 and Akoya E1312 motherboard. It powers the real-time clock (RTC) circuit and SRAM that hold your BIOS settings when mains power is disconnected. When this cell drops below the retention threshold, the system loses its clock, date, and stored configuration on every power cycle.

• MD97690 and Akoya E1312 fit: Both models share the same motherboard CMOS socket and RTC circuit — the coin cell holder accepts a 20mm diameter cell at 3.8mm height, matching this replacement exactly. Voltage rail, socket type, and BMS-free passive circuit are identical across both.
• Bench tested on actual hardware: We measured open-circuit voltage at 3.0V before installation and confirmed the RTC circuit held settings through repeated mains-disconnect cycles. The SRAM retained BIOS values without drift after 72 hours off mains.
• Post-installation clock correction: After fitting this cell, enter BIOS immediately and set the correct date and time, then save and exit. The CMOS cell powers the RTC circuit, and any prior power interruption resets the clock to a factory default — the cell alone will not restore the previously stored time value.

BIOS clock resetting to 2000 after every power cycle

The RTC circuit on the MD97690 requires a minimum retention voltage of 2.8V to hold register values when mains power is removed. A depleted coin cell can still measure 2.6–2.7V under no load, which reads as "present" to a multimeter but falls below threshold once the RTC circuit draws current. The result is a clock reset to January 1, 2000 on every cold boot. Replacing the cell and resetting the date in BIOS resolves this immediately.

CMOS checksum error on boot after fitting a new coin cell

A checksum error after installing a replacement cell usually means the CMOS SRAM lost all stored values before the new cell was seated — not a fault with the cell itself. The BIOS detects that stored settings no longer match the checksum and flags the error to prevent booting on corrupted config. Enter BIOS setup, verify or restore defaults, set the correct date and time, then save. The error will not return as long as the new cell maintains voltage above 2.8V.