System battery voltage is low


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System battery voltage is low

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I have a 100 desktops of the type Dell optiplex 780. All seem to work fine except 1.

This particular desktop boots with the error "System battery voltage is low" Press F1 to continue. F2 for setup and F5 for diagnostics.

I've been googling and checking forums for days now. Finding different answers. But so far none of them work.

I already replaced the CMOS battery. Even switched the old one to another desktop. And it works fine. So battery can't be bad.

Also tried to discharge the battery, like a colleague suggested by putting it in upside down for 10 secs.

I've plugged the pc in different power outlets with different cables. Since there were some messages saying this might be a issue. But other pc's on these have no issues.

So i'm 100% sure something is wrong with the desktop machine. Any ideas except calling a tech?

All Replies

    You need to thank your colleague, you never put a battery in upside down.

    You probably burned out part of the circuit and mobo can't see battery.

    You discharge cmos by unpluging the computer and removing battery then

    press and and hold power buttom in for about 30 seconds.

    The battery is NOT rechargeable so why would you need to discharge it?

    Never put a battery in upside down, that destroys the circuit.

    Hope this helps.


  •  stefanovitch85

    Try the following solution from this POST and see if it helps. Quote:

    To get the motherboard to recognise this new battery properly you have to power cycle the computer 3 times (switch it on, get it to POST then switch it off again).

    After the third power cycle the low voltage alert message should disappear.

    If the alert message still displays, double check the output voltage of the replacement battery.

    It should read anywhere from 3V to 3.2V.

    If it does then the sensing circuit on the motherboard it faulty.

    You could also, try clearing the event log in System Setup [BIOS].



    If my answer was helpful, please use the 'Did this answer the question' and click: Yes
    Forum Member since 2001
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  • And make sure the battery socket is clean and you didn't leave any fingerprints on the battery when you installed it. Hold it by the edges or with a lint-free cloth.


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    Forum Member since 2004

    I am NOT a Dell employee