HP EliteBook 6930p CMOS Replacement Battery 3V 200mAh

HP EliteBook 6930p — 3V Lithium CMOS Backup Battery

This is a 3V, 200mAh lithium coin cell that powers the CMOS chip on the HP EliteBook 6930p motherboard. It keeps BIOS settings, system configuration, and the real-time clock alive when the laptop is unplugged or the main battery is removed. When this cell fails, the system loses its settings every time mains power is cut.

• EliteBook 6930p motherboard fit: The 6930p uses a non-rechargeable lithium cell soldered or clipped to the motherboard to back the RTC circuit and CMOS SRAM. This replacement matches the physical footprint at 30.10 × 20.12 × 4.12mm and the 3V nominal voltage the retention circuit requires.
• Bench tested on actual hardware: We confirmed the cell holds above the 2.8V CMOS retention threshold under the micro-ampere draw typical of RTC and SRAM backup. The BMS on this circuit is passive — the cell simply must stay above that floor to prevent a settings wipe.
• Post-install clock correction: After fitting this cell, enter BIOS immediately and set the correct date and time, then save and exit. The RTC circuit resets to a factory default value on first power-up after the swap, and the system will flag a time error on every boot until you correct it manually.

BIOS clock resetting to 2000 after every power cycle

The RTC on the EliteBook 6930p is backed exclusively by the CMOS coin cell. When the cell drops below 2.8V, the RTC loses power the moment mains is removed, and the clock defaults to a hardcoded date — typically January 1, 2000. The main battery does not back this circuit; only the coin cell does. Replacing the cell and then setting the correct date in BIOS resolves this completely.

CMOS checksum error on boot after fitting a new cell

A checksum error immediately after a coin cell swap usually means the CMOS SRAM was fully wiped before the new cell went in — the stored checksum no longer matches the default values. The fix is straightforward: enter BIOS setup, load default settings, set the correct date and time, then save and exit. This writes a fresh checksum that matches the current CMOS contents. The error will not return as long as the new cell stays above 2.8V.