Question re: “A major addition to hardware maintenance”

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This week’s newsletter has a piece by Fred Langa about failing PC batteries.  Do desktops (as opposed to laptops) in fact have batteries?  And, if so, should I look into the case of our 13-year-old Dell desktop, to see if there’s a problem?

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Desktops do have batteries but anything made in the last 25 years usually has just a small coin-cell that isn’t susceptible to this type of failure.

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All desktops that I have seen have had a battery.  It is usually a CR2032, looks like a quarter, in a clip on the motherboard.  It allows the clock to keep running even if the computer is unplugged, and sometimes I think it powers memory to prevent bios settings from resetting.  They usually last more than 5 years, and the first sign of trouble is after a power outage the desktop on boot says something like invalid bios settings, press function key to enter bios.  Or, when it boots the time is wrong.

If the battery is removed, it should read at least 2.9 volts when tested with a multimeter to be still usable.  Replacements should be a brand name like Energizer, Duracell, Sony, Panasonic, Toshiba or Maxell.

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SueW, Slowpoke47

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Yes, they have. Those are usually CR2032 batteries. CMOS batteries are used to power BIOS (or UEFI), even when computer’s power supply is plugged off. If those batteries are failing, you may encounter many issues, like BIOS (and so, computer), fogetting date, custom boot device order etc.

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Slowpoke47

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There are batteries to maintain the BIOS or CMOS settings. The most common thing you will see if that battery fails is that the computer will start up saying time and date are not correct.
The most common battery is a CR2032. Its a 3 volt “coin” cell. Cost is $0.50 – $10.00 depending on where you purchase it/them.

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Slowpoke47

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Slowpoke47 I was going to ask the same question. Thanks for being quicker.

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Something’s awry with this topic – there are several posts awaiting moderation here yet other topics are almost immediately moderated.. Still just in case..

Some BIOS systems allow you to check the battery with the PC health page. If not the plain flat area with the plus on it is the positive (no surprises there!) and I’ve never knowingly or obviously damaged anything checking with a DMM on the 20V range between the exposed positive part of the battery and a motherboard screw or (safer for jumpy hands or large probes) the metalwork on the outside of the port sockets which is also grounded.

The only complication is some batteries are vertically mounted (Eg Asus p8h61 series) and for some reason Gigabyte decided to use the laptop battery presentation (enclosed in heat shrink fitted with a connector on a wire) – it was positioned behind the ports (literally stuck to the back of the USB ones) next to the port for the optional mini PCIE WiFi option.. but I can’t remember the model and 99% plus chance you wont need to know..

I’d read a new cell, and if your used one is over 0 .2V lower then the new cell voltage, replace it. Meters aren’t that accurate – usually +- 3 on the last digit and a range which goes 200mV, 2V, 20V means at 3V the +-3 error range is more than you’re looking for in voltage change.

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Slowpoke47

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oldguy wrote:

there are several posts awaiting moderation

We don’t have full time moderators so be patient.

cheers, Paul

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Responses much appreciated.  I’m familiar with those wafer batteries, have various ones including CR2032 on hand.

This machine has its original battery, 13+ years old.  I’m no stranger to the case innards- added/replaced several HDD’s as well as, 8 or so years ago, the power supply.

While I do have a good Klein multimeter, and I’m, as they say, not afraid to use it, why not just replace the cell with a new one?  Is there a downside to a brief power interruption while doing that?  If so, I can probably use a couple of jumpers to avoid that gap.

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If you’ve already got the case open, I’m with you – just replace the battery. I’d use that Klein on the new battery, though, just to make sure it’s good. I bought a three pack of AA batteries once and they were all dead!

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Slowpoke47

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Well- it’s no big deal to open the case- just a coupla screws.

Re the dead batteries- happens more often than you might think.  And on the other end of that, I’ve had so-called “battery testers” that were in truth disguised paperweights.

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DrBonzo

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Think I’ll start a side business – selling battery testers and batteries.

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Slowpoke47

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I’ve never heard of people using jumpers to prevent the power outage although there could be a way.  If you take a photo of all bios settings before replacement, and after set the time after and reset any changed bios settings, you should be fine.  Check the new cell before putting it in, if possible install one that is close to 3.3V for longest life.

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Slowpoke47

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