CMOS Battery
Reddit take
AI summary of the Reddit excerpts below — not a quote
CMOS batteries, typically CR2032 coin cells, are essential components that allow motherboards to retain BIOS settings and system time. While they are inexpensive and widely available, their failure can cause significant issues ranging from clock drift to complete boot failures. User experiences vary significantly based on motherboard design, with some finding replacement trivial and others facing complex disassembly.
Pros
- Inexpensive and widely available at most retailers
- Standardized sizes (usually CR2032) make finding replacements easy
- Replacing a dead battery can resolve persistent boot loops and BIOS reset issues
Cons
- Physical access can be difficult on some motherboards, requiring removal of heatsinks or VRM covers
- Failure can cause confusing symptoms like the system failing to boot into the OS
- Some motherboard designs use proprietary locking mechanisms or plastic clips that are difficult to manipulate
Caveats
- Always verify the specific battery model (e.g., CR2032) by checking the motherboard manual or the existing battery
- Button cell batteries are a significant safety hazard for children and must be kept out of reach
- Replacement may require thermal pad replacement if the battery is located under a chipset heatsink
Best for
- Fixing systems that lose BIOS settings or time after being powered off
- Troubleshooting older motherboards that fail to post or boot into the OS
- Routine maintenance for PCs that are several years old
Avoid if
- You are uncomfortable with full PC disassembly (for motherboards where the battery is hidden behind the board or under heatsinks)
- The system is under a warranty that might be voided by removing motherboard shrouds
This summary uses balanced time weighting with about a 6-month half-life. The evidence is based on a small sample of 13 mentions from r/buildapc with a median age of 194 days.
Sentiment
6 positive (46%) · 3 mixed (23%) · 4 negative (31%)
Trust + time weighted score: +17% · raw score 15%
What redditors said (10 of 13)
For Cmos: Get the same type battery, look at the mobo manual or whats written on the batter), its like cr2023 or something.
You can replace it. Its a pain in the ass to get to. Its either under the VRM or chipset heatsink and youll have to remove some screws behind the board to get them off. There are likely thermal pads as well so be mindful of that.
CMOS battery is dead and will need replacement in order for the motherboard to retain system information. You mentioned all of this because of one measely coin cell battery that died.
get a name brand one, dont get a dollar tree random brand and it will all be fine.
They’re also saying beware the buttoncell battery and keep it away from kids, so I think the cmos battery is replaceable.
Have a look at the battery, it should be a CR2032 which are common and found almost anywhere. Yeah you can change it no problem.
Only after replacing, all issues disappeared.
My dead CMOS battery prevented my old ASRock Z97 from fully booting twice. Start to boot. Never boot into OS.
Aside from a can of compressed air and a new CMOS battery, should I be worried?
I replaced it, it was a really painfull experience :)), bottom right corner heatsink covering it and it had 4 screws behind motherboard...., i had to dissasemble the entire PC almost to remove the heatsink and also the system that's holding the battery had a stupid design, you have to remove a plastic thing between the clips that was blocking the unlocking mechanism. Literaly couldnt unlock the battery until i removed the plastic thing.
Compare
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