Member Avatar for Yzk

hi everybody,

I have an old computer stored up in my attic. Its from 1994, a P1 200 Mhz. For shame, her battery had run out. So I had a new computer. And it was forgotten, until now. Now my question is:
are all CMOS battery's the same?

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Short answer: not exactly. Most desktop motherboards use a 3‑volt lithium coin cell for the RTC/CMOS backup, but the exact size, thickness and the way it is mounted can vary. and were right to say “open the case and check” — the battery and board marking tell you what to buy. (lifewire.com)

Coin cells share chemistry and nominal voltage, yet differ mechanically and in capacity. CR2032 (20.0 mm × 3.2 mm) is the most common; CR2025 and CR2016 have the same diameter but are thinner and hold less charge, so a different code can affect fit and lifetime. Always match the CR number or exact dimensions, not just “3 volts.” (digchip.com)

Mounting matters: some boards have a snap/clip holder, some laptops use a small wired plug or a glued/spot‑welded tabbed cell. If the cell is tabbed or soldered, use a replacement with the same tabs or consult the service manual — do not solder directly to a coin cell (manufacturers warn against that). If the battery is hard‑to‑reach or soldered, a service shop is a safer option. ()

Quick checklist (practical follow‑up to ’s and others’ tips):

  • Power down and unplug before opening the case.
  • Note the battery code and orientation (+ side usually faces up).
  • Replace with a battery that matches the CR number or exact dimensions.
  • After install, enter BIOS/UEFI to set date/time and any custom settings.
  • Dispose/recycle the old cell safely.

Manufacturer guides and repair KBs cover the step‑by‑step replacement and safety notes. (answers.openeye.net)

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Member Avatar for Catweazle

I'm pretty sure they're all 3 volts. Most Pentium class or later PCs should use the round, clip-in batteries.

But check on the board, just to be sure it's not an older style one, soldered to the board.

I've never really seen those on anything later than a 486 though.

Any electronics store will stock the batteries you need.

Member Avatar for DMR

As Catweazle said, your best bet is to crack the case and check the model/part # of the battery. Many are the flat, round "watch-style" (CR-2032 or similar), but not all.

Member Avatar for MAD_DOG

http://www.batterypower.net/

Yeah looks like there all really the same.

commented: Just to let you know, I respect how you decided it was time to sort your life out. I'm impressed. +10
Member Avatar for MAD_DOG

There are so many more but, just typed it in google and got that one I really never needed a CMOS battery maybe once so I just took it out of a old motherboard. Anywho.

Member Avatar for DMR

That's the basic shape, yes. You do want to check the actual CRxxxx or whatever part # though, as the diameter of those style of batteries does vary. Also, there's often no need to hunt for the batteries online. Those types are pretty common; I can usually find them at my local drug store or Radio Shack for a couple of $$.

Member Avatar for Catweazle

heh heh..

I guess i'm a bit 'rough and ready' in my own appraoch. I'd just grab the old one toddle off to an electronics store or other stockist, and tell 'em i want one same size, same voltage. If it fits it's OK!

The voltage is the crucial thing, because it powers CMOS and clock, and you don't want THOSE buggered up or there's gonna be problems!

Member Avatar for MAD_DOG

Yeah just bring it in some store like RadioShack or something show them the battery and tell them you want a new one. Or just say you want a battery for your CMOS battery for your Motherboard I am sure they will give you the right one. Besides it's only what 2 dollars?

Member Avatar for Yzk

So the answer to my question is.
That not all CMOS batteries might not be compatible with most motherboards?

Member Avatar for Catweazle

The simple answer is - not necessarily, no.

You'd not likely strike problems, but take the old one with you for comparison and ID when you buy the new one and there's no problem.

Member Avatar for MAD_DOG

If your too lazy buying a new battery at a store try the spare one you have in the garage it isn't going to hurt you.

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