A Complementary Metal-Oxide-Semiconductor (CMOS) battery is located on a computer’s motherboard. It powers the CMOS memory chip that stores important system settings, such as the time and date, BIOS or UEFI configurations, and other hardware settings.
The following newer Razer Blade models, starting from 2025, no longer use a coin cell battery.
- Razer Blade 16" (2026) | RZ09-0581x
- Razer Blade 18” (2025) | RZ09-0529x
- Razer Blade 16” (2025) | RZ09-0528x
- Razer Blade 14” (2025) | RZ09-0530x
Here are the functions of a CMOS battery:
- Keeps time and date - Powers the real-time clock so the correct date and time are maintained even when the computer is off.
- Saves BIOS settings - Preserves BIOS configurations across restarts, preventing them from resetting to defaults.
- Supports faster startups - Maintained BIOS settings help the system boot quickly and load the operating system properly.
- Assists power management - Helps manage low-power modes like sleep and hibernation efficiently.
Here are the symptoms of a failing CMOS battery:
- Time/date reset - The system clock resets or displays an incorrect date and time after the Razer Blade is powered off or unplugged.
- Extended boot time or multiple reboots - The system takes longer than usual to boot or automatically restarts two to three times during initial startup after AC power is removed.
- Slow boot - The system takes longer to start as BIOS settings are reloaded each time.
- Error messages - Warnings related to CMOS or BIOS settings appear during startup.
- Hardware detection issues - Certain components are not recognized or configured correctly by the system.
- BIOS settings reset - Custom BIOS configurations revert to default values.
If you notice these symptoms, the CMOS battery needs to be replaced. See the answer below for instructions.
If you are not comfortable performing this task, seek professional assistance.
