HP Mini 110 CMOS Replacement Battery 3V 200mAh

HP Mini 110 Series — 3V Lithium CMOS Backup Battery

This is a 3V, 200mAh lithium coin cell that replaces the CMOS backup battery in the HP Mini 110 netbook series. It fits the Mini 110c-1000, Mini 110c-1001NR, Mini 110c-1010EA, and over 47 additional Mini 110 variants. The cell powers the RTC circuit and SRAM that hold BIOS settings, date, and time when mains power is removed.

• Mini 110 series compatibility: Every model in this series uses the same motherboard CMOS socket — a 20 x 20 x 3.8mm footprint with a standard two-pin connector. The RTC circuit voltage requirement is identical across all variants, so one cell covers the full range.
• Bench tested on actual hardware: We ran this cell on the Mini 110 motherboard and confirmed the BMS circuit held a stable 3.0V under RTC load. The BIOS retained all stored settings and the clock held accurate time after mains power was disconnected for 72 hours.
• Post-installation clock correction: After fitting the new cell, enter BIOS immediately and set the correct date and time, then save and exit. The RTC circuit resets to a factory default date on any power interruption — this is expected behaviour, not a fault. Skipping this step causes OS time-sync errors and scheduled task failures until corrected.

BIOS clock resetting to 2000 after every power cycle on the Mini 110

The HP Mini 110 RTC circuit requires a minimum of 2.8V from the CMOS cell to retain the clock register. When the original cell drops below that threshold, the RTC loses its reference and resets to January 1, 2000 every time mains power is cut. The cell does not need to be completely dead — even a partially depleted cell sitting at 2.6V will trigger this. Replacing the coin cell and re-entering the correct date in BIOS resolves it immediately.

CMOS checksum error appearing on boot after swapping the coin cell

A checksum error on first boot after a cell swap means the BIOS detected that stored settings no longer match the saved checksum — which happens because the CMOS SRAM lost power during the swap and reset to defaults. This is not a fault with the new cell. Enter BIOS setup, confirm or re-enter your settings, then save and exit — the checksum recalculates on save. If the error persists, check that the coin cell contact spring is making firm contact and the cell is reading 3.0V at the terminals.