Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Do desktops have batteries?

  1. May 17, 2016 #1
    A Google search only yielded whether they have CMOS batteries, but I'm referring to batteries that if you were to unplug your computer it would go off.

    I opened up a mini Desktop and just saw a motherboard without any large battery anywhere, so I'm guessing no? I would like to be sure however.

    Thanks in advance
     
  2. jcsd
  3. May 17, 2016 #2
    No. Desktops are usually connected to an external power backup in case the power goes out. Some have minimal batteries, but they're designed to last basically just long enough for the computer to properly shut down.
     
  4. May 17, 2016 #3
    Thanks, my concern arose from having a battery fail before the computer does.
     
  5. May 17, 2016 #4

    berkeman

    User Avatar

    Staff: Mentor

    The Real Time Clock module will generally have a small battery. And it does have a limited lifetime -- that's why some older PCs do not have an accurate time anymore and have to be reset when powered up. And since it can also be responsible for storing BIOS information (in older PCs before cheap serial flash memories were available), it can cause other problems and need to be replaced.

    http://www.makeuseof.com/tag/why-does-my-motherboard-have-a-battery/
     
  6. May 17, 2016 #5

    rbelli1

    User Avatar
    Gold Member

    In modern desktops those batteries are almost always 2032 size coin cells. Usually they are replaceable with nothing more complicated than a small prying device. Often the lever is operable with your finger. The clock may run the wrong speed long before you get any other faulty operation. If it is not keeping the correct time it is time to replace the battery.

    When they get low you can sometimes get odd operation. As I recall, intel's 810 series of chipsets would lock up when the battery went dead. Te revive them you needed to go through a certain series of actions when replacing the battery. Just popping in a new one would not work.

    BoB
     
  7. May 17, 2016 #6
    Thanks guys that clears it up for me. Desktops have no batteries for the whole system.
     
  8. May 18, 2016 #7

    rbelli1

    User Avatar
    Gold Member

    Except when you are connected to a UPS. There are UPS designs that are installed internally in a spare drive bay.

    So there are some rare cases where the desktop has a battery to run the whole system. The run time is generally just long enough to save your work and shut down. It is not for general use.

    BoB
     
  9. May 18, 2016 #8

    FactChecker

    User Avatar
    Science Advisor
    Gold Member

    I think it is wise to have a UPS for a desktop PC. I have one that will power the PC, monitor, and a small LED lamp for a short time so I can close files I am working on and shut it down if the power goes out. (My power does out a LOT at unexpected times.)
     
  10. May 18, 2016 #9

    OCR

    User Avatar

    Very wise... my power goes off at unexpected times, too...

    UPS.JPG
    UPS1.JPG
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted