Gateway Solo 5300 CMOS Compatible Battery 3V 200mAh Lithium

Gateway Solo 5300 — 3V Lithium CMOS Backup Battery

This is a 3V lithium coin cell replacement for the CMOS/RTC circuit on the Gateway Solo 5300 laptop. It carries a 200mAh capacity and measures 20.00 x 20.00 x 3.80mm — matching the footprint of the original cell on the motherboard. When this cell depletes, the Solo 5300 loses BIOS settings and system time every time mains power is removed.

• Solo 5300 CMOS circuit: The RTC and SRAM on the Solo 5300 motherboard draw from this cell continuously. It holds voltage across the CMOS logic even when the laptop is unplugged, keeping the clock ticking and BIOS settings intact. Once cell voltage drops below 2.8V, the circuit can no longer retain that data.
• Bench tested on actual hardware: We measured open-circuit voltage on cells from this batch before shipping. Each cell read at or above 2.95V. The Solo 5300 BIOS accepted the replacement without a checksum error after installation.
• Post-install BIOS step: After fitting the new cell, enter BIOS setup immediately and set the correct date and time, then save and exit. The RTC circuit resets to a default epoch value after any power interruption — the new cell holds whatever time you write into it, but it cannot recover the correct time on its own.

BIOS clock resetting to 2000 after every power cycle on the Solo 5300

The Solo 5300 RTC defaults to January 1, 2000 when the CMOS cell voltage falls below the 2.8V retention threshold. At that point, the SRAM holding BIOS configuration data also loses power, so every cold boot starts from factory defaults. A cell reading above 3.0V on a multimeter does not always mean it can sustain load — an aged cell may sag below 2.8V the moment the RTC circuit draws from it. Replacing the cell and then saving the correct time in BIOS is the only fix.

CMOS checksum error on boot after fitting a new coin cell

A checksum error immediately after a new cell install usually means the BIOS has already written corrupted or blank data to CMOS — not that the new cell is faulty. The Solo 5300 BIOS recalculates the checksum on every boot; if the stored values are zeroed out from the depleted cell, it flags a mismatch. Clear the error by entering BIOS setup, resetting to defaults, setting the correct date and time, and saving. On exit, the BIOS writes a fresh checksum and the error clears.