Ah, but you can eat them afterwards...Maybe cheaper, but probably generally more bulky - and, of course, they rot & go mouldy, too (much more rapidly than batteries)Good point. I was given a 'potato clock' at Christmas (two different metal strips; supply your own potato). Not a bad idea. Potatoes are cheaper than batteries!... but batteries in parallel can be unpredictable, particularly if they don't age/deteriorate at the same rate - if the voltage of just one drops, all the others will discharge into it!
Kind Regards, John
can't you?