No, activating ErP mode does not drain the CMOS battery.
No, activating ErP mode does not drain the CMOS battery.
I've turned on ErP mode in BIOS to switch off the LAN port lights when the PC is powered down. I'm wondering if this feature affects the CMOS battery usage. When ErP is active, does it supply power to the mainboard or the small memory storing BIOS settings? If so, will turning ErP on cut that power, forcing the motherboard to rely solely on the CMOS battery to maintain BIOS data? I haven't found a definitive response after searching online. My Asus B760-Plus D4 board is involved.
Searching online indicates it can still supply up to 1W of 5VSB power in ErP mode, which suggests it might keep charging the CMOS battery. This could be misleading since ErP Lot 6 limits it to less than 0.5W, accounting for conversion losses and basic standby needs—so I’m unsure if CMOS charging is included. Additionally, not every device uses a rechargeable CMOS battery; some rely on disposable ones lasting up to ten years.