My slip of the keyboard, sir. [Pulls forelock.] I wrote 'trickle', which you took to mean TRKL (5V), when I should have written 'dribble', hereinafter referred to as DRBL (5V).
TRKL is an indispensible facet of soft-power management, as all of us who suffer from the Astec villains of the IIcx/IIci/Q700 gang well know, and not confined to just those Macs. In the CCs, because they also have an on/off mains switch behind, it is a variant that Apple calls pseudo-soft power, but that doesn't diminish what TylerEss wrote.
In complete distinction is DRBL, which I did mention in a prior post by its 'correct' name, here. It is the reason why PRAM batteries in desktops can last as long as their shelf-lives in Macs that are permanently connected to an active mains supply.
The effect of that was adequately summed-up by Allan Jones, here:
'On any Mac, PRAM battery life is hugely extended by leaving the computer plugged into wall power at all times. A trickle of power bypasses the power supply to power the PRAM even it (recte: if) the computer is turned off. If you unplug or cut the power at a power strip, the battery has to do all the work to maintain PRAM information and the battery life can fall from years to months.' Apart from Allan's and my having (seemingly) read the same books and looked at the same circuit-diagrams, I have found, unfailingly during the last 20-odd years, that it works.
It could be added that, in the case of say, iMac CRTs, if resetting the PMU is mismanaged, that lifetime reduces even further, to overnight. A pain, but not the fault of the battery.
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