Lifespan of a PRAM Battery In a Mac Classic II

#1 Tue, 2 Mar 2010 - 16:35 68kMLA

Does anyone know how long a replacement PRAM battery that is a decent brand (SAFT) will last in a Mac Classic II that is in storage?

The PRAM battery in a Mac Classic II I bought recently is shot (couldn'y get any reading other than flat 0 on my multimeter) and I want to replace it. However, I only plan on taking this Mac Classic II out to play once or twice a year, so I want to know how long a PRAM battery will last in a Classic Mac that will be in storage for extended periods of time. If it's only for a short time then I'll just live with the PRAM being blank, but if I can get at least a few years our of each battery then it might be worth it.

Any insight is appreciated.

#2 Tue, 2 Mar 2010 - 18:08 68kMLA

If you are just storing the machine, remove the battery.

Batteries in machines that are used a decent amount (are plugged into main power) should last 4+ years.

#3 Tue, 2 Mar 2010 - 22:20 68kMLA

5 - 10 years.

#4 Tue, 2 Mar 2010 - 23:10 68kMLA

Those are two wildly disparate answers...

Can anyone else confirm either of the above posts is correct?

#5 Tue, 2 Mar 2010 - 23:25 68kMLA

I can confirm with all my certainty that those answers are either surely correct or incorrect.

#6 Tue, 2 Mar 2010 - 23:34 68kMLA

I read 10 years on the battery manufacturers site, but I'm guessing it's closer to 5-6 from what I've seen on my other computers.

Tempest

#7 Wed, 3 Mar 2010 - 00:02 68kMLA

As of August 2007, My Mac II's original soldered on batteries were still holding 3.6v. I haven't checked it recently, though.

#8 Wed, 3 Mar 2010 - 00:08 68kMLA

I got 10 years from a Mac G3 battery that died just a few months ago. It was the original battery which held the manufacture date of 1998.

#9 Wed, 3 Mar 2010 - 02:28 68kMLA

Are these machines you guys had plugged in or just sitting around in storage?

#10 Wed, 3 Mar 2010 - 02:38 68kMLA

I read 10 years on the battery manufacturers site, but I'm guessing it's closer to 5-6 from what I've seen on my other computers.
Tempest

10 years is the shelf life I bet, manufacturers do not give a use rating since that depends on what you do with them.

The life depends on your use factors. Machines that use the battery to start are much harder on them then those that do not (Mac II, IIx, IIfx for starters with 2 batteries). If the machine is a soft start and you leave it plugged in I would think the battery will last 10 years. A machine left in storage will not last anywhere near that long.

If I didn't get 4 years out of a new fresh battery with the limited use I put the machines through I would be mad.

#11 Wed, 3 Mar 2010 - 02:48 68kMLA

Are these machines you guys had plugged in or just sitting around in storage?

My Mac II had been sitting in storage for years... even before I got it... I've kept it plugged in since finding out that the battery was good. I should test it again soon though. It is certainly the exception NOT the rule.

#12 Wed, 3 Mar 2010 - 04:35 68kMLA

If there are no shorts, or failing caps (partially shorted) the battery should last another lifetime of the machine