New half-AA lithium batteries cost USD4 each from at least one eBay seller. If PRAM batteries are 'spared' by permanent attachment of the Mac to the live mains (but not switched on) they will last from 5-7 years. That is close to their 'shelf' lifetimes, and it makes for an insignificantly small battery running-cost. There is no practical advantage to removing the batteries between uses of the Macs, considering the time and effort involved in doing so in the compact AIOs.
Capacitor degeneration is a real possibility in the Macintosh to Plus group, which use a scarce, costly, 4.5-V cylindrical alkaline battery. The battery is easily accessible without opening the case, but removing the battery does nothing to prevent capacitor degeneration, and nothing to preserve the battery. On the other hand, if the original capacitors have not bulged or leaked by now, they are not about to do so imminently. If they do leak, the fault is in their manufacture, and not in the trickle current that spares the battery.
So all-in-all, there is little advantage in removing the batteries unless you plan storage/idle times of years or more. I have 28 Macs in my study, and that includes 13 desktop 68000 and 68030 machines, all permanently connected to the mains. Any one of them can thus be started up at a moment's notice. None of them has developed leaky capacitors in the last seven years, and those that arrived so were cleaned-up when they arrived. YMMV, naturally, while Murphy lives, but the state of your Macs' batteries and boards is not one that needs to do dreadful things to your intimate apparel.
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Capacitor degeneration is a real possibility in the Macintosh to Plus group, which use a scarce, costly, 4.5-V cylindrical alkaline battery. The battery is easily accessible without opening the case, but removing the battery does nothing to prevent capacitor degeneration, and nothing to preserve the battery. On the other hand, if the original capacitors have not bulged or leaked by now, they are not about to do so imminently. If they do leak, the fault is in their manufacture, and not in the trickle current that spares the battery.
So all-in-all, there is little advantage in removing the batteries unless you plan storage/idle times of years or more. I have 28 Macs in my study, and that includes 13 desktop 68000 and 68030 machines, all permanently connected to the mains. Any one of them can thus be started up at a moment's notice. None of them has developed leaky capacitors in the last seven years, and those that arrived so were cleaned-up when they arrived. YMMV, naturally, while Murphy lives, but the state of your Macs' batteries and boards is not one that needs to do dreadful things to your intimate apparel.
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