System turns off even with UPS

TechPrince

Broken In
I have APC BACK-UPS ES 650VA 230V INDIA Offline UPS with software, Cooler Master eXtreme Power Plus 700W PSU both under warranty. My computer runs for 20+ hours per day.

UPS Output Power Capacity : 390W
Typical recharge time : 5 hours


Situation #1 (Works fine)
Load on Battery Backup : 100-130W
UPS switches to battery backup and provides the given mins of uptime without any problem.
Tested in random over-voltage/blackouts/fluctuation events as well as in manual blackout testing.

Situation #2 (Problem)
Load on Battery Backup : 300+W but < 390W
UPS switches to battery backup but sometimes computer turns off immediately in any event like there was no ups installed.

Now the reasons can be
1) Battery is exhausting in split second.
2) Battery was not charged completely.
3) My power supply is faulty and its loosing the charge before the switching occurs / UPS is switching after my power supply looses its charge on load.

I am using APC Powerchute software. The software has High voltage sensitivity selected, it shuts down the computer when battery backup has <=5 mins remaining (all default values).
Now this software shows that i have 100% charged batteries, battery passed its self test showing batteries are working normally.
But sometimes when the load is more than 300W, even a small fluctuation restarts my computer.
So now -
If batteries are getting exhausted in split second then the software should show the changed battery value on next restart but it shows 80-90% charged.
If battery wasn't charged completely then their software should reflect that low charge value OR computer should turn off in few mins in manual test (turning main switch off and let my computer run on battery backup).
If my power supply is faulty then it should turn off my computer in any case on any load, but it works without problem when load is low (<300W) and sometimes gives problems on high load (300w+). However i am not sure about capacitors charge holding time on load in my PSU.

I told my problem to APC Service Executive since these problems started to happen after connecting UPS (wasnt happening before). The dude says to turn off your equipment and UPS and let the UPS charge from ac power source for 5 hours, many software shows wrong values (including their own apc powerchute).
Its an offline UPS, my computer runs for 20+ hours , software shows 100% battery time as well.

So where is the problem? PSU or UPS or something else? I am more inclined towards UPS switching fault on high load.
 
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RCuber

The Mighty Unkel!!!
Staff member
I also faced such problems with another APC UPS, the culprit was a desi PSU. We upgraded to home UPS, it handles fine on regular use( FSP Saga II 500W PSU) , but when gaming I sometime face restarts during power failure. my doubt would be on the PSU.
 
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I also faced such problems with another APC UPS, the culprit was a desi UPS. We upgraded to home UPS, it handles fine on regular use( FSP Saga II 500W PSU) , but when gaming I sometime face restarts during power failure. my doubt would be on the PSU.
I believe you meant PSU. please edit it.
 
OP
TechPrince

TechPrince

Broken In
It turns out to be Active PFC related issue. My PSU has Active PFC >0.9, so PSU is capable of drawing x1.25 power, so 700x1.25 = 875W during initial burst. UPS cant handle this burst hence drops the power. Another problem is small humming sound when PSU runs in battery mode of UPS is due to wave type. They are recommending to buy pure sine wave UPS to solve humming problem and a UPS with higher capacity than PSU to solve Active PFC PSU related problems.

Now the problem is to handle 875W, i would need 1500VA UPS. If i am right then considering the efficiency of my PSU of 80% = 560W, 1000VA should suffice. Now to find a pure sinewave 1000VA UPS which doesnt cost 10k.....
Source : http://www.apc.com/support/index?pa...ale=en_US&searchid=1366285424098&locale=en_US
 
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