Surely the CMOS battery will last for ages anyway.
I follow much the same path as wee eddie. On shutting the computer down I switch off the surge-protected multiway bus at the wall.
Losses in the various low voltage power supplies (Printer, External HD etc,) merely being live, make a total of 17 watts with nothing actually switched on.
This rises to just under 200W when the computer is on and in available mode.
So there's the decision, and IMO its a no-brainer.
Either a possible two or even three CMOS batteries in a very long life, or a standby use of about 17W day and night for years, that is one unit for every 60 hours or so just doing nothing with the computer!
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