My 3 Macs all require a 3.2 - 3.6v lithium-ion battery. They're expensive (NZ$20 ea). While shopping for something else, I came across some Lithium batteries, one of which looks similar in size to the worn-out one from my iMac. I will check that for certain in a week's time. However the replacement (and much cheaper) Lithium battery I looked at - Model CR2 - was only 3v. It is intended for a camera. My question is: would a 3v Lithium battery be sufficient to keep the MacOS PRAM, clock, etc going? Might there be damage to the dependent circuit from insufficient voltage?