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Old 09-22-2012, 01:11 AM   #23
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Join Date: Dec 2009
City & State: Prague, 504'52.22"N, 1423'30.45"E
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Default Re: Can I test or operate APC Smart UPS 2200 off a single RBC7

Originally Posted by vsmGuy View Post
Attached is a clip of the sound that comes from the 22uF, 150V bipolar yellow capacitor(s) in both the models when charging the batteries.

At 45s into the recording, I turn off the line power - notice how the noise goes away completely when it's running off batteries in the 1000VA (the one which was running when I recorded the noise)

I am sure you will agree this is very different from the gentle hum of a transformer?

If this is a characteristic sound of APC UPS when the batteries are dying, I would like to know if there's a battery I can buy, from say Walmart or Home Depot etc just to see if a new battery makes the noise go away.
Ah, you mean this. I heard that too with two BackUPS (those are the power cords with battery) and yes, both had pretty much dead batteries. Swaped for good (well, with 2/5 of nominal capacity, but working normally) just for testing and it was OK again.
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