MP 1,1-5,1 Mac Pro 5,1 CMOS Battery Questions

[danallen]

I have a 2012 Mac Pro 5,1 running macOS 15.6 via OpenCore Legacy Patcher.

I have never given much thought to the CR2032 battery. Recently I started reading about it and came across claims that a weak or missing battery can cause loss of the selected startup disk, NVRAM settings, clock settings, and possibly result in occasional boot issues such as a flashing folder with a question mark while the Mac searches for a bootable volume.

First, are those claims accurate for a Mac Pro 5,1?

Second, is it realistic for a CR2032 battery in a Mac Pro 5,1 to remain functional for more than a decade? I received this machine in 2014, and I am curious whether it is plausible that the battery could still be doing its job after all these years.

I would appreciate hearing from anyone with direct experience regarding battery life and the actual consequences of a weak or missing battery in these machines.

 

[Bigwaff]

Yup, all true. Also, you would want to replace w/ a BR2032 rather than CR2032. The BR2032 is designed to handle the high heat inside a computer. I would replace -before- things go sideways. Replacing is not difficult but you need to take care not to snap off the little clamps that hold the battery in place when removing the installed battery.

 

[bmoraski]

Yup, all true. Also, you would want to replace w/ a BR2032 rather than CR2032. The BR2032 is designed to handle the high heat inside a computer. I would replace -before- things go sideways. Replacing is not difficult but you need to take care not to snap off the little clamps that hold the battery in place when removing the installed battery.

This.

 

[danallen]

Yup, all true. Also, you would want to replace w/ a BR2032 rather than CR2032. The BR2032 is designed to handle the high heat inside a computer. I would replace -before- things go sideways. Replacing is not difficult but you need to take care not to snap off the little clamps that hold the battery in place when removing the installed battery.

Thanks for letting me know.

I am looking at these batteries on ebay, listed as though a batter can be a BR2032 and a CR2032 at the same time. How can I be sure I have a good enough one of these batteries?

p.s. Here is an upside to the unfortunate news regarding vmware on sequoia not able to make linux vms......because of the way that all came right as info came in, and you owned the correction, now I know I can totally trust what you report. Ironic but true

 

[reader50]

The BR2032 gets drawn from when your Mac Pro is unplugged from power. The clock circuit uses mains power if available - the battery is only a backup. My 2009 has been a primary machine for the previous owner, and myself. So it's virtually always been plugged into power.

I replaced my original BR2032 last year for good luck, but its voltage reading was still good. So to answer your question, yes it is possible your original battery is still good. Even after all this time. If you've been plugged into power all along.

As to eBay, if a battery says it's both, then it's likely a CR2032. They are interchangeable - the only difference is the temperature rating is higher for a BR. Check the product pic - if the product doesn't say BR, it isn't one. Scroll down the listings - you can get actual BR2032 batteries. They're just buried amongst all the CR2032s.

 

[MarkC426]

Thanks for letting me know.

I am looking at these batteries on ebay, listed as though a batter can be a BR2032 and a CR2032 at the same time. How can I be sure I have a good enough one of these batteries?

p.s. Here is an upside to the unfortunate news regarding vmware on sequoia not able to make linux vms......because of the way that all came right as info came in, and you owned the correction, now I know I can totally trust what you report. Ironic but true

View attachment 2636936

All consumer batteries (Duracell/Panasonic etc) will list multiple specs, but they are not suitable.
You need an ‘actual’ BR battery.

BR-2032/BN | Panasonic Button Battery, 3 V, 20 mm Diameter | RS

uk.rs-online.com

 

[bmoraski]

Just get the BR2032.