Apc 450 - very noisy on batteries

[Anonymous user]

Hi,

i have a 1u apc 450 ups.  When I first power it on, it makes a very very loud buzzing noise for a few seconds and then goes pretty much silent in normal use. When the mains power is lost and it runs on batteries the buzzing returns. It is REALLY loud.  Not just a small background hum but a really loud buzz that remains as long as it's running on batteries.  Is this normal? Thanks!

[prince213_apc]

Hope its not fan noise. Other than that the problem will on the inverter circuit which kicks in at startup and during power failure.

[Anonymous user]

Thanks - definitely not fan noise, WAY much louder than that.  So it's not normal, you think inverter circuit faulty and I need a replacement?  It's only a few months old but has done this since day one and it's my first unit so I have no comparison.  At first I just thought that's how it was but on reflection am thinking it can't be right.  But I don't want to go down the route of a replacement if it is normal!

[prince213_apc · Accepted solution]

Please make a video of its working when on power failure.