Macintosh IIx battery longevity?

[techknight]

I have a Macintosh IIx I rebuilt a little over a year and a half ago. maybe 2 years. 

I was prepping it to get rid of it, and noticed the batteries were flat. 

So I was wondering if anyone has replaced the PRAM batts and how long they got out of them sitting around? 

 

[joethezombie]

Not a IIx, but I put new batteries in a IIfx in August 2015, and they're still at full voltage.

 

[unity]

7 years is typical. As we know, even today some black Vartas in SE (the wired ones) still hold voltage and enough amperage to work just fine.

 

[Compgeke]

Which batteries did you use? I recently had a Newertech battery from late 2012 die on me in my 9600, a bit early IMO.

 

[rsolberg]

Don't the batteries in the II, IIx, and IIfx supply power to ADB for the keyboard power on button? Maintaining that in addition to PRAM and RTC with no mains power could conceivably chew through batteries much more quickly than in other Macs.

 

[techknight]

I know. Thats why I was wondering if anyone knew how long they last when not under power. 

It was those little orange specials that came from uniserver from time to time.