UPS AC output problem

[BillP]

Hello,

i have the ups model APC BK650MI and i have the following problem,
when the Ups is on AC power the output is 220 Volts (Thats ok) but
when i disconnect AC power output drops toy 170 Volts.
The battery of the ups is new and checked.
Does this problem means that i have electronic problem ?

Please help ...

[Anonymous user]

Hi
Can I talk You directly?
shindvs@gmail.com

[Anonymous user]

infrared wrote:
I measure the voltage with a voltmeter (NOT true RMS). When the Ups is on the ac voltmeter says 226 volts witch is OK but when i plug of the AC (ups is on battery ) then
volts are dropped to 170 volts (having or not load on the ups). If i have load then the connected device (a simple PC for example) turns of immediately when AC power disconnects
I open UPS and i measure the battery and its says 13.7 volts and i think is OK besides the battery is 2 days old.
Is this normal ?

Yes, the voltage reading is normal. You're reading 226v on AC power, because it's sinusoidal. You're reading 170v on meter, because the meter can't properly read the modified squarewave.

It's not normal that your PC shuts off when you disconnect the AC to UPS. Does the UPS shut off as well?

[BillP]

I measure the voltage with a voltmeter (NOT true RMS). When the Ups is on the ac voltmeter says 226 volts witch is OK but when i plug of the AC (ups is on battery ) then
volts are dropped to 170 volts (having or not load on the ups). If i have load then the connected device (a simple PC for example) turns of immediately when AC power disconnects
I open UPS and i measure the battery and its says 13.7 volts and i think is OK besides the battery is 2 days old.
Is this normal ?

[Cap1_apc]

Infrared,

How are you measuring the output? This unit will output a stepped approximated sine wave when on battery power. You will need a true RMS voltmeter to get an accurate reading of the voltage here.

Does the unit drop the load when on battery power?

You definitely want to read into kbase 1493:
http://nam-en.apc.com/cgi-bin/nam_en.cfg/php/enduser/std_adp.php?p_faqid=1493&p_created=1010390400&p...

null

[Anonymous user]

The power quality from that and many other consumer UPSs isn't anywhere near as good as the main line. The output on UPSs are almost always modified square wave unless otherwise stated.

To measure the voltage on a modified squarewave inverters and UPSs, you'll need a True RMS meter. Not advocating for one brand, but an example is the Fluke 87 series. Multimeters are almost always "typical responding" or not true RMS. True RMS is a feature most meter manufacture would make sure to get printed on the front cover.

[Anonymous user · Accepted solution]

Yes this unit dropping load when battery power. What should I do now?