Albany Creek, Queensland, Australia
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My UPS is beeping

If your UPS is beeping then assuming the lights are on so the mains power is on and it is not overloaded by having too many things plugged into it, a UPS will beep if the batteries have failed.

This can be serious for several reasons;

  • the connected load has no protection from over or under voltage so these conditions may cause damage or data loss
  • the batteries can get very warm possibly causing a fire hazard
  • they may start to leak causing damage
  • if they have swelled up then it may be impossible to remove the batteries from the UPS without major surgery. This is particularly the case in 1U rack mount UPS’s.

Once the battery light is on then they are well and truly past their use-by date.

The batteries shown below were removed from an APC SmartUPS 3000 2U rack mount UPS manufactured in 2013 and were hot to the touch. I believe they are original so have done well to last 6 years – about double their accepted lifespan. UPS’s hold their batteries in a variety of different ways. This one uses a tray full of small batteries. in a series/parallel arrangement to provide the necessary voltage and current.

Fortunately, although tightly packed in the tray there was still enough clearance so the swollen batteries did not prevent the tray from being removed from the unit. Replacement battery packs are available from the manufacturer but a more economical solution is to repack the tray with fresh batteries and dispose of the old ones correctly. This is done, one at a time until all 8 batteries are replaced. You need to ensure that the replacement batteries are the the same voltage and current rating and physical size as the existing ones along with the correct terminal size.

Most UPS’s allow hot swapping of the batteries so the connected load does not need to be turned off. Of course, if you happened to have a power failure while the batteries are out then the connected devices will immediately lose power but with failed batteries the same thing would occur.

This was the worst of the batteries and only showed 7 volts when measured with a digital meter and 5 volts on an analogue meter which loads the battery more.  Batteries need to be replaced before they get to this stage. Contact us for assistance to arrange a pro-active replacement or if your UPS is beeping.Swollen battery

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