Corsair CX550 issue with UPS

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I recently got a corsair CX550 psu & for first 4-5 days it worked perfectly but then it started having a strange issue.Whenever there is a power cut & I am playing some video with madvr using 1050Ti(for those who don't know madvr improves picture quality by using gfx card for running its upscaling algorithms so load is very similar to running a game) system just shuts down along with long constant beep from UPS indicating overload.This does not happen when system is idle/not playing any video.

However the strange thing is that my FSP 400W psu works perfectly in same situation & even able to provide backup to system(playing same video) for at least 30 seconds(manually turned off mains power to UPS but didn't tested beyond that) proving that UPS batteries have enough capability left even after 14 months(intex generic 600VA UPS).

So my question is for those who use activePFC psu like CX550(or any recent usually recommended psu because they all come with activePFC nowadays) with your usual intex/luminous/zebronics etc UPS.Do these psu works fine with a 600VA UPS when under load with a low power gfx card like 1050Ti?

Tagging @gta5 @chimera201 for your inputs.

Well the hold up time for CX550 seems to be about 12ms according to Cybenetics tests which is less than the recommended 17 ms. Possibly the cause for the shutdown.
*www.cybenetics.com/code/pdf.php?id=CUj

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Thanks for this crucial info.Any idea about APC 600VA UPS holdup time & if possible FSP Saga II 400W/similar psu holdup time.Currently I have Intex 600VA UPS which works fine with FSP but not with CX550.

It's not hold up time for UPS but rather transfer time. Also there would be some additional delay between the UPS and PSU so it won't be exact value to value match. Basically the transfer time needs to be much lesser.
Seems it's 10ms for 600VA APC one:
*www.apc.com/salestools/JGNY-9477YW/JGNY-9477YW_R1_EN.pdf

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As far as I know

I don't think it is because of hold up time..

Hold up time is usually measured at full load, so that 12 ms figure is if you are using your PSU at full load it will only be able to power up your pc for 12ms after power is removed

Your total pc power consumption won't be more than 250 watts even at full load with this cofig, so your hold up time would be more than 25ms roughly.

Additionaly if hold up time was responsible then PC would restart .. Here I don't think PC is restarting but complete shutdown with overload beep..

Also most decent ups won't have transfer time of more than 10ms

This is most likely because of high inrush current , apfc psus have high voltage primary capacitors and they draw a lot of current at start regardless of actual load and can be very high more than even full load .. PSU uses NTC thermistor for this purpose to limit inrush current , but still they will draw a lot of current.. Depending upon the size of ntc thermistor and size of primary capacitors used, apfc circuitry it can vary

At low loads , inrush current isn't high to trigger overload condition of UPS , plus capacitors will be less discharged because of low load at idle and will draw less inrush current
Till the time ups resumes

But at high loads , primary capacitors would discharge faster , resulting in more inrush current on top of already high demanding main PC load

This differs from PSU to PSU. Some can use beefier primary caps like in high wattage models but they may have appropriately sized thermistors to even play well 600 va ups like for eg RM650x of member topgear mentioned in his thread

Computers containing PFC (Power Factor Corrected) power supplies and their use Back-UPS and Smart-UPS SC with Step Approximated Sine waves.

Your fsp unit may simply be drawing less inrush current at full load than cx550

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That's some good info @gta5 .Does this mean I have to get a 1000/1100VA ups & just getting a 600VA APC ups won't be enough?That's a lot of unnecessary money spend for a system that draws less than 300W(I will upgrade pentium G620 to a Ryzen 3 1200 or 2200G in future but gfx card will remain 1050Ti).

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You have a main sinewave inverter right ? And you use that to power your PC during power cuts ?

Remove UPS

If your inverter is able to sustain the load when you are playing movie during power cut , then why not directly use that..

It is safer than back ups

Maybe APC 600va may have higher tolerance for inrush current than your current one .. Which may be enough to power your load.. There is a slight chance it could be battery also

Maybe 800va might work , you will have to do hit and trial to see which one will suit.. "Nothing can be said with sureity"

Or maybe try microtek/luminous ones etc of higher Va as they are cheaper, since you only need to run this for few milliseconds till your main inverter resumes power .. You can get these on trial basis I think because of wide availability in offline shops, if you can't arrange one from friend etc for testing

.. Pay a few hundred extra to dealer , and return in few hours after buying if it doesn't work

But still if your sinewave supports your load , then that is the best option.. And no expenditure + Safer for PSU

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whitestar_999 said:
I recently got a corsair CX550 psu & for first 4-5 days it worked perfectly but then it started having a strange issue.Whenever there is a power cut & I am playing some video with madvr using 1050Ti(for those who don't know madvr improves picture quality by using gfx card for running its upscaling algorithms so load is very similar to running a game) system just shuts down along with long constant beep from UPS indicating overload.This does not happen when system is idle/not playing any video.

However the strange thing is that my FSP 400W psu works perfectly in same situation & even able to provide backup to system(playing same video) for at least 30 seconds(manually turned off mains power to UPS but didn't tested beyond that) proving that UPS batteries have enough capability left even after 14 months(intex generic 600VA UPS).

So my question is for those who use activePFC psu like CX550(or any recent usually recommended psu because they all come with activePFC nowadays) with your usual intex/luminous/zebronics etc UPS.Do these psu works fine with a 600VA UPS when under load with a low power gfx card like 1050Ti?

I had this exact same problem few years back and again a few months ago. I used a Corsair HX650 PSU with APC 700VA UPS. It used to work fine when the system was idle or not playing any games but the system shut down/restarted when I was playing a game during the power cut. Manually switching off power supply didnt cause a restart.
Both the times this happened when it was close to my battery replacement dates. Since my UPS was already 6years old, I replaced it with a Numeric 1kva and haven't had any abrupt shutdowns or restarts. Hope this helps

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^^Can you tell me how old were the APC ups batteries when this problem started(you said UPS was 6 years old) & how much the numeric 1kva costed you?

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gta5 said:
You have a main sinewave inverter right ? And you use that to power your PC during power cuts ?

Remove UPS

If your inverter is able to sustain the load when you are playing movie during power cut , then why not directly use that..

It is safer than back ups

Maybe APC 600va may have higher tolerance for inrush current than your current one .. Which may be enough to power your load.. There is a slight chance it could be battery also

Maybe 800va might work , you will have to do hit and trial to see which one will suit.. "Nothing can be said with sureity"

Or maybe try microtek/luminous ones etc of higher Va as they are cheaper, since you only need to run this for few milliseconds till your main inverter resumes power .. You can get these on trial basis I think because of wide availability in offline shops, if you can't arrange one from friend etc for testing

.. Pay a few hundred extra to dealer , and return in few hours after buying if it doesn't work

But still if your sinewave supports your load , then that is the best option.. And no expenditure + Safer for PSU

The thing is inverter is meant for whole house & because of long power cuts sometimes it runs out of battery.There are also regular voltage fluctuations in mains power resulting in my inverter regulating it & then UPS doing some correction(aka click sound) many times during day so I thought of using UPS as an extra layer of protection/backup.I am thinking of buying a 600VA APC UPS if its batteries can last for 2-3 years & it can support my CX550 during powercut/switchover.

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whitestar_999 said:
The thing is inverter is meant for whole house & because of long power cuts sometimes it runs out of battery.There are also regular voltage fluctuations in mains power resulting in my inverter regulating it & then UPS doing some correction(aka click sound) many times during day so I thought of using UPS as an extra layer of protection/backup.I am thinking of buying a 600VA APC UPS if its batteries can last for 2-3 years & it can support my CX550 during powercut/switchover.

If inverter runs out of battery , you will hardly get 10-15 minutes extra with UPS.. Which I assume is not going to be on a regular basis .. You can monitor when power has been gone for long and accordingly close PC when you feel inverter might give up..

With or without UPS you are going to be dependent on inverter either way so it will not affect backup time of inverter for whole house and other equipments

Regarding fluctuations , I don't think you have to worry about it ..
Unlike many other budget PSUs
Cx supports full input range from 100-240v
It should automatically handle fluctuations between 180-230v .. Below that your inverter might switch to battery mode itself in wide UPS mode.. Or maybe it's 160 depending your inverter support range in this mode

It is better you try this and see for a week how does it play out , Cx 550 without UPS directly connected to inverter.. If it is able to sustain the load + fluctuations then this is much better

I mentioned this point in PM regarding UPS-PSU , going with 600va means taking that same risk again , it may or may not work , so unless you have a pre- arrangement with dealer for returning in case it doesn't work , don't go for it .. At least look at 800va or some numeric,microtek to save cost higher VA models if you want to go for a UPS

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dexterz said:
I had this exact same problem few years back and again a few months ago. I used a Corsair HX650 PSU with APC 700VA UPS. It used to work fine when the system was idle or not playing any games but the system shut down/restarted when I was playing a game during the power cut. Manually switching off power supply didnt cause a restart.
Both the times this happened when it was close to my battery replacement dates. Since my UPS was already 6years old, I replaced it with a Numeric 1kva and haven't had any abrupt shutdowns or restarts. Hope this helps

Thanks for sharing your experience..

Did it used to restart or did it used to shutdown completely with long overload beep ? And what was your cpu / gpu ? Did you change PSU or gpu anytime?

Also you mentioned that this happened only close to battery replacement dates.. Before that when you used to play games your pc never shutdown/restarted even once during power cuts between those years when your battery was healthy ?

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whitestar_999 said:
^^Can you tell me how old were the APC ups batteries when this problem started(you said UPS was 6 years old) & how much the numeric 1kva costed you?

Batteries were 2 yrs old and the numeric cost 4k from dealer in Ritchie street

Sent from my ONEPLUS A5010 using Tapatalk

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gta5 said:
Thanks for sharing your experience..

Did it used to restart or did it used to shutdown completely with long overload beep ? And what was your cpu / gpu ? Did you change PSU or gpu anytime?

Also you mentioned that this happened only close to battery replacement dates.. Before that when you used to play games your pc never shutdown/restarted even once during power cuts between those years when your battery was healthy ?

It has done both restart and long beep shutdown. I changed from hd 7850 to gtx1060. But restart happened with both gpu. I use i5 2500k and gtx1060 now. Dont remember it restarting when battery was healthy.

Sent from my ONEPLUS A5010 using Tapatalk

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gta5 said:
But at high loads , primary capacitors would discharge faster , resulting in more inrush current on top of already high demanding main PC load

I have a seasonic 520w psu. Any idea, how much more will it draw above and beyond the 520W? upto 600w? 800VA ups fails to provide backup at full load.

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UPS actual power output is usually 60% of VA rating so for a 600VA UPS it is (0.6*600=360W) & for a 800VA UPS it is (0.6*800=480W). If your system is at full load above 480W then obviously your UPS will shut down(or UPS batteries are dying & unable to provide even a few seconds of 480W backup).

Umm... I still think it's the holdup time. The inrush will trigger if the capacitor discharges and the capacitor keeping it's charge is called holdup! The holdup isn't enough compared to the UPS's transition time and the inrush/overload is happening as a side effect.

What is the FSP's exact model? We know the CX550 has like 12 ms holdup according to cybenetics.
Also I noticed the cheaper APC UPS has transfer time written as 10 ms 'typical'.
I checked a higher VA model and it has written it as 5ms typical, 10 ms 'maximum'. So the higher VA model also has better transfer time.
*www.apc.com/salestools/JGNY-96UETV/JGNY-96UETV_R0_EN.pdf

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FSP Saga II 400W.Also check out this thread by me on jonnyguru forums(currently at 99 replies!):
Facing a strange issue with Corsair CX550 - jonnyGURU Forums

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Transfer time of ups is not fixed everytime, so they mention typical and maximum time..

Also hold up time for his load will be much longer .. If you take 12ms figure at 100% load . Then his load is 150 watts max

550/150 x 12 - that is more than 35ms easily for his config/system .. That's a lot.. It will not be exactly like calcultaion due to various factots but roughly similar , atleast easily far more than required >25ms

Hold up time is the least likely cause because of this reason

Inrush current is also there with fsp , but itsn't as high that it is overloading UPS

@whitestar_999 did you try running it on inverter at least 2-3 times ? To see if it restarts ?/overload

The second cause maybe batteries , which may not be able to power a higher power draw but fine for lower load with fsp

21.6ms for FSP

*img.purch.com/o/aHR0cDovL21lZGlhLmJlc3RvZm1pY3JvLmNvbS9SL0IvMjYxNDc5L29yaWdpbmFsL2hvbGR1cF90aW1lLnBuZw==

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UPS batteries are working fine with FSP with same system load that shuts down CX550 with UPS overload beep(playing a video file with madvr that loads ~65% of 1050Ti as per gpu-z). So the only explanations left are: a)high inrush current or b)degraded transfer time of UPS(14 months old) less than CX550 but more than FSP Saga II.

@gta5 CX550 worked fine with inverter when I checked it for 2 days but currently I am again using FSP with UPS.Because it is summer so voltage fluctuation is quite high sometimes during day making UPS constantly making clicking sounds at a duration of 1-2 seconds(I then turn off power to UPS for 2-3 minutes & let system run on UPS till fluctuations are gone).I am not sure it is a good idea to directly connect system to inverter without UPS at those times.

^^which media player do you use and what settings? I just tried madvr with media player classic now(I am using madvr for the first time) and played a 4K video. GPU is being utilized and usage was 14%-35% with 14% majority of the time. I have corsair cx450 and radeon HD 7770 by the way.

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What resolution screen are you using?Madvr's most taxing algorithms are for upscaling so if you try to play a 480p/720p 25/30fps video on a 1080p screen using high quality settings(removing compression artifacts & NGU for upscaling) then it should easily load 1050Ti/similar card to ~70-80%. For 60fps 720p/1080p video on a 4k screen even a 1070 will not be enough at high quality settings.

P.S.I am playing a 13 years old 640*480p avi xvid video file on 1080p screen using madvr with pot player(not relevant as load on gfx card remains almost same with mpc-hc too).

1600 x 900, it is a 20" LG monitor.

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That's why

on doom9 forum I have seen people complaining about even 1080 not able to run smoothly some videos at highest quality madvr settings.

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@rijinpk1 can you do a simple test if possible? run mpc-hc with madvr & a high quality 720p video(bitrate 4-5mbps) & then use NGU(sharp) in madvr upscaling algorithm while simultaneously running some cpu benchmark(like prime 95) if gpu-z show 7770 load below 60-70%.Then turn off the mains power to UPS(which brand is yours & how old are its batteries) for 2-3 seconds & see if your system stays on.

will do it tomorrow and revert.

I switched off the mains for almost 10 seconds and system was working fine. I am using V-guard slender plus 600VA(300W) UPS which is 6 years old and battery was changed about 7-8 months ago.

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Thanks!Are you using CX450 after getting new batteries or from before that?My issue is that UPS works fine with another 400W psu(non activePFC) & can easily give backup of at least a minute with heavy system load but with CX550 it just overloads with any power cut.I am not sure if even changing batteries will help,it seems either issue is with UPS or psu.

My theory is that your UPS's total transfer time is between 12ms and 21ms. CX550's holdup is 11.93ms and FSP's is 21.6ms. FSP has enough holdup time to support the transfer. Even higher than the 50Hz cycle (20ms). Either you have to get a UPS with less than 10ms transfer time or a PSU with >20ms holdup time.

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I understand this point but then why UPS is still able to work fine with CX550 under low load condition(aka just downloading in background with nothing else).Is it because transfer time required by CX550 depends on load at the time of power cut?Also there was no issue in the first 3-4 days of using CX550 with UPS & there were power cuts in that period incl when system was under moderate load.

whitestar_999 said:
I understand this point but then why UPS is still able to work fine with CX550 under low load condition(aka just downloading in background with nothing else).Is it because transfer time required by CX550 depends on load at the time of power cut?Also there was no issue in the first 3-4 days of using CX550 with UPS & there were power cuts in that period incl when system was under moderate load.

That is as explained by gta5 that the capacitors would discharge faster under load. Your UPS's transfer time is probably cutting very close to the CX550's holdup. Under load it exceeded it. As for the first few days it worked fine, it could be that the UPS or PSU degraded later. More likely the PSU since it was taking in the simulated sine wave.

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I heard something similar on jonnyguru forums too.Is it possible to know/measure this "degradation" of psu or UPS?I mean if psu is "degraded" does this mean CX550 transfer time is now even less than 11.93ms or does this mean that my UPS transfer time is now more than 11.93ms(my UPS is iball 600VA around 14 months old with stated transfer time of 4-8ms).Is it possible to get UPS repaired to improve transfer time?

I don't think they will repair it to improve it's transfer time. In India repair happens when something is broken. But your UPS is functional for them since they will test it on their own PSUs that has enough holdup. I would suggest getting an APC one.

Here this guy says the same thing:
Corsair CX550M – farewell group design

^ He also fixes it in the conclusion.

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1) again, it is meaningless to consider Hold up time without taking into consideration the

"System load"

hold up time is not static/fixed, it is totally dependent on load

Just like you cannot talk about battery life/runtime of smartphone without taking into account load/usage pattern.. You can run the same phone for days on standby or you can deplete the battery in just 3 hours or so if you play intenisve game continuously..

Or

From your UPS , You can get backup time of only 5-10 minutes if you run your pc under heavy load or you can get more than an hour of backup time from same ups if you only power a bulb or something

The primary cap of PSU works like a mini battery that holds charge..

"Both" the tests given in those links are measuring hold up time at
"100% load of PSU"

Whitestar is not even running his PSU at more than 30% load..

Here , check this graph of a typical PSU of 250 watts

See how hold up time varies in relation to load a lotttt..

At 250 watts it has 25ms or so , at 150 watt it is 50ms , at 50 watts that is 140 ms or so

*www.artesyn.com/power/assets/reference/appnotes/an55.pdf

For whitestar system load , his hold up time is easily more than 25-30 ms .. So this is why hold up time highlyyyy unlikely to be the reason..

2) Afaik transfer time of UPS is not mainly dependant on load .. It is mainly dependant at which point on AC sinecurve cycle does the power is lost.. But in any case genrally a decent UPS will not have more than 12 ms transfer time

His UPS works fine at low system load and also under load with his other psu suggesting transfer time is not the problem.. Unless you think that somehow transfer time has "coincidentely" degraded "so much" and landed just right around 30ms or more .. More than cx but less than fsp ( 50ms roughly 400/150x20 )..

Possible but very very less chances of that coincidence.. Even then it would be UPS at fault

3) his PSU under load works fine with his Inverter ..

4) rijin's, quiky008 PSU works fine with roughly similar hold up times with their UPS

Hold up time is highlyy unlikelyyy to be the reason thus..

Will post more later

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@chimera201 see post#28 @rijinpk1 did a test on my request & his UPS is only 300W(as per specifications but his transfer time is stated as 4ms) while his system draws more power(an i3 vs pentium dual core & a 7770 vs 1050Ti) with a CX450.I just want to be clear about it before buying a new UPS in future for my next system upgrade as psu will be CX550.

@gta5 if @rijinpk1 can use his CX450 with a 300W UPS with more system load than mine then why do you think it still might not work with my CX550 if I get a new 600VA APC UPS.

whitestar_999 said:
Thanks!Are you using CX450 after getting new batteries or from before that?My issue is that UPS works fine with another 400W psu(non activePFC) & can easily give backup of at least a minute with heavy system load but with CX550 it just overloads with any power cut.I am not sure if even changing batteries will help,it seems either issue is with UPS or psu.

PSU is only about 3-4 months old. you may have to try some trial and error method, I suppose- with another UPS,another active PFC PSU.

whitestar_999 said:
I heard something similar on jonnyguru forums too.Is it possible to know/measure this "degradation" of psu or UPS?I mean if psu is "degraded" does this mean CX550 transfer time is now even less than 11.93ms or does this mean that my UPS transfer time is now more than 11.93ms(my UPS is iball 600VA around 14 months old with stated transfer time of 4-8ms).Is it possible to get UPS repaired to improve transfer time?

hold up time is measured at 80% load afaik. even if you stress your system components to 100%, you are not going to use the half the power the PSU can supply. 1050 ti doesn't even need a pcie power connector, right?

@gta5 I understand the holdup time is not fixed. I never considered it to be fixed. But the thing is holdup is about capacitors keeping its charge. And inrush happens if the charge is getting depleted.

You bolster the inrush only theory by saying the charge will get depleted faster if "under load" causing inrush.
And you refute the holdup theory by saying the charge will not get depleted under "low load".

^ Both the above statements are contradicting each other.
And the "holdup to load" relation is exponential/logarithmic not linear. It will be very high under very low loads like <50W. But it will quickly drop to 10-20ms when the load is increased (>50%). The problem here is a combination of the UPS having a high transfer time as well as the PSU having a low holdup. The PSU caps might have been degraded as well.

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If you weren't considering it fixed , then taking 11ms figure for whitestars system load is a bigg error.. That is what I was pointing at.. That figure was measured when PSU was outputting 550 watts in both the tests.. Hence taking that same figure for 150 watt outputt will lead to wrong conclusion

chimera201 said:
And you refute the holdup theory by saying the charge will not get depleted under "low load".

I didn't say this ..

This is what I said

At low loads , inrush current isn't high to trigger overload condition of UPS , plus capacitors will be less discharged because of low load at idle and will draw less inrush current
Till the time ups resumes

But at high loads , primary capacitors would discharge faster , resulting in more inrush current on top of high PC load

Primary Capacitor will also get discharged at low load , since it will take some minimum 4-6ms for UPS to switch regardless of load.. But since load is low it will get discharged very less in the same amount of time and thus less inrush current plus less system load and Not 0 inrush current..

That less inrush current at low load is well within the limits of UPS , hence it works with low load..

And the "holdup to load" relation is exponential/logarithmic not linear. It will be very high under very low loads like <50W. But it will quickly drop to 10-20ms

Yes , at every 50% of load , hold up time would roughly get double

Let's take 10ms as an example..
So,
550 watts - 10ms
275 watts -20ms
137.5 watts - 40ms
68 watts - 80ms
34 watts - 160ms and so on..

Like I mentioned before, In reality it will not be exactly like it but "roughly" in the same ballpark due to other factors involved..

Check the link of that 250 watts power supply again.. And look at that graph.. Here

250 watts - 27ms
200 watts - 35 ms
150 watts - 47ms
100 watts -72ms
50 watts - 145 ms

Roughly it will follow similar pattern

So for whitestar load even if you take 8 ms figure as worst case at 100% load , his hold up time at 150 watts should easily be more than 25ms at the minimum .. 550/150 x 8ms.. Which is way more than required

So you see why hold up time is highllllllyyy unlikely to be the cause ,

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@gta5 according to the test done by @rijinpk1 his CX450 was able to handle inrush current at almost 100% system load & which is more than my system load(i3 vs pentium dual core,7770 vs 1050Ti) on a UPS that is rated 300W so shouldn't this exclude inrush current theory as well because CX450 & 550 are similar design wise.If his system can work with a 600VA UPS with a CX450 then surely my system should work too with a new 600VA UPS which however as per you is risky because of your inrush current theory.

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rijinpk1 said:
hold up time is measured at 80% load afaik. even if you stress your system components to 100%, you are not going to use the half the power the PSU can supply. 1050 ti doesn't even need a pcie power connector, right?

Yes,1050Ti is without any power connector.It draws power from pci-e slot only.

what I think is that since the UPS is a pseudo sine wave one, the output at high load without mains may be too distorted to handle by the active PFC PSU cx550 which is actually expecting more or less a sinusoidal wave. non-APFC PSUs will not have this problem.
A good UPS might solve the issue. This is just my assumption, may be far from truth! Try if you can find a UPS just for testing.

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whitestar_999 said:
@gta5 according to the test done by @rijinpk1 his CX450 was able to handle inrush current at almost 100% system load & which is more than my system load(i3 vs pentium dual core,7770 vs 1050Ti) on a UPS that is rated 300W so shouldn't this exclude inrush current theory as well because CX450 & 550 are similar design wise.If his system can work with a 600VA UPS with a CX450 then surely my system should work too with a new 600VA UPS which however as per you is risky because of your inrush current theory.

There are too many possible scenarios here..

1) what if your current UPS in "reality" has a low threshold for inrush current than the theoretical 300-360 watts ? Maybe even less than rijin's UPS ?

not talking about powering a steady load , but instantaneous surge ..

2) what if batteries are not able to power a higher "instant" power draw but fine for lower power draw like with your fsp as a result your UPS is giving overload beep and dropping load completely ? ( to me this is less likely but since Per sir at JG said this point , so i am just mentioning it )

All we know is your UPS is able to handle your system load and inrush current of your FSP , which is lower than 550..

If that is the case then moving to a new good 600va UPS like apc should solve the problem

But here is why I still think there may still be some risk involved..

Your PSU actually uses a bigger primary cap than 450 , (since your psu has to handle 550 watts while providing similar hold up time of 450 )
the advantage is that for your given 150 watt load you get a longer hold up time than 450...

But increasing the primary cap size increases the inrush current .. If they simultaneously have not increased NTC thermistor(inrush current limiter) then your PSU may end up with higher inrush current than 450.. Like I mentioned previously it mainly depends upon interplay of both these , and some other minor factors and differs from PSU to psu.. While a point can be made that your system load is also lower .. But without actual measurements nobody can tell ..

Rm650x of topgear works fine with his 600va UPS ..

And there is a big point that rijin's PSU is GW , with different design than yours..

And also cx 550 already didn't work with your current 600va .. So... There are reasons that it will work is not 100% guranteed

You should contact him , he is using 1050ti with 600va with 550 ..

Suggestions for UPS

And ask him if it is fine if his UPS is handle under load and his variant

I think there are good chances that a good apc 600va will work fine , but there is a risk involved .. So you better make pre arrangements with the dealer just in case it doesn't work.. And return it.. To be on safe side

Better yet , can't you borrow or "rent " another UPS even if its 600va from somebody for few hours ? See what happens and That will help you in forming decision

This is a very common issue if you search around other forums , and most people solved it by moving to a higher VA ups..

Btw this inrush current is not just a theory , this is what APC have said themselves n their faq I linked before.

Also the point regarding damaging cap .. This is also very less likely given how so many people are using apfc PSU from all brands with 99% ups not being pure sinewave for years without any harm and also even on inferior quality primary capacitors

So your cap degrading "so fast" in just a month , not to mention your primary cap is a high quality Japanese one..possible but highly unlikely to happen this fast

W

@gta5 thanks for the detailed reply.I have posted in that thread for feedback about apc ups with 1050Ti & cx550.The thing is there is no option between APC 600VA & 1100 UPS & I don't want to spend 5.5k on 1100VA UPS.Getting a 800VA UPS from cheaper brands(champion or microtek) is another option but then I think if I need to replace it within 2 years then it isn't worth spending.Getting a cheaper 1000/1100VA ups from cheaper brands also doesn't look much good as difference between their price & 1100VA APC ups is ~1.3k which is not much considering APC much higher quality.

Won't find a better explanation than this:
*pqlit.eaton.com/ll_download_bylitcode.asp?doc_id=11666

Requirement Four—
Transfer to backup power faster than PSU “hold-up” time
Power supply units inside IT equipment have an energy storage device, typically a capacitor, that stores enough energy to keep the device running during very brief power interruptions (milliseconds). This is known as “hold-up” time and depends on the internal capacitance of the power supply and the output power rating. At higher output power, the energy is drawn from internal capacitance faster than at lower output power.
According to IT equipment standards set forth by the SSI Forum, minimum hold-up time at fully rated output power is one cycle. At 50 Hz (most of Europe and Asia), this translates into 20 ms. At 60 Hz (the standard in North America), one cycle would be 16.7 ms. Since most IT equipment is designed for the global market, the minimum hold-up time is 20 ms and may be longer at lighter loads. However, the trend is toward shorter hold-up times. Under pressures to reduce PSU size and cost, manufacturers are designing PSUs with smaller capacitors, which leads to shorter hold-up times. This effect is somewhat offset by the prevalence of redundant power supplies, since each power supply would be loaded to less than 50 percent of its capacity.
A related issue with respect to hold-up time is the peak inrush current (Table 1) required to charge up the capacitor that provides the ride-through capability. When first connected to an AC power source (or when powered up on an already connected source), the equipment temporarily draws a large inrush current that can last for 2–10 ms and be as much as 10–60 times the normal operating current.

Similar to the start-up inrush current, there is also a surge current drawn to recharge the capacitors after short interruptions in power (Figure 8). If the power interruption was less than five ms, surge currents will typically last for half a cycle (10 ms) and will be less than 300 percent of nominal current. For interruptions of 10-15 ms, the surge current could be 700 to more than 1000 percent of nominal current, and can last for 1.0–1.5 cycles (20 ms–30 ms).

Implications for UPS design
UPS performance requirement: The UPS must ensure no interruption in its output that lasts longer than the hold-time of the IT equipment’s PSU. This means that the UPS must have an acceptable transfer time for all transitions between different modes of operation—such as from normal operating mode to battery mode and back again, or between high-efficiency mode and double-conversion mode for new energysaving UPSs.
Note that hold-up time will be different for single- or multi-corded servers, because the more PSUs on the IT equipment, the less power load on each PSU, and the longer the available hold-up time. Looking at it another way, single-corded IT equipment will need a UPS with faster transition times, to prevent unplanned shutdowns and reboots.
Transfer time should actually be much faster than the maximum allowable hold-up time, because the longer the PSU goes without power, the larger the surge current it will draw when it receives power again.
In cases where the PSU is without power for more than 5–10 ms, the inrush current required by the PSU could easily exceed the maximum current output capacity of the UPS inverter, forcing the UPS to shut down to protect its own inverter components.

As a result, Eaton recommends using a UPS with a transfer time of less than 5 ms, if the UPS will be loaded to 70 percent or more of its capacity. Rapid transfer time helps prevent a UPS overload condition that could cause a system failure. To prevent problems with large inrush current during initial start-up or restart, most UPSs will feed the IT equipment directly from the utility source at that time.
Considerations for branch circuit breakers. The AC source supplying the PSU must also be able to support inrush current without tripping any breakers. This factor becomes especially critical if several pieces of IT equipment are served from the same circuit. All of this equipment draws inrush current simultaneously after a power outage. It is important to either size the breakers accordingly (using breaker types that have a trip curve compatible with the expected load), or sequence the start-up to reduce system-level inrush current.

At no point does it suggest to get a higher VA UPS.

gta5 said:
So for whitestar load even if you take 8 ms figure as worst case at 100% load

Now this is where you are wrong. You assume the transfer time of the iball UPS as advertised.

G

Now you now see how hold up time is highllllllyyy unlikely to be the cause

Thanks for that link , a much more detailed proof for what I have said

Please read that and my replies again

I have said exactly the same thing they are saying

Here

the inrush current required by the PSU
could easily exceed the maximum current output capacity of the UPS inverter, forcing the UPS to shut
down to protect its own inverter components.

It's after this statement they are saying what you have bolded

As a result, Eaton recommends using a UPS with a transfer time of less than 5 ms, if the UPS will be
loaded to 70 percent or more of its capacity. Rapid transfer time helps prevent a UPS overload condition
that could cause a system failure

They are trying to not overload the UPS of a given size , when it will be running at a higher load of"70% or more ".. [ deliberately fixing 1 part of the equation ] the only way to do this is by shortening transfer time, and thus reducing inrush current as a result of not allowing caps to discharge heavily , which is what I have said previously

Or you can have a long transfer time of ups at the cost of higher inrush current ( means higher VA UPS required to avoid overload )

Now that less than 5ms Transfer time of UPS is highly difficult to get .. Plus they are mainly talking about high loads

Look at apc 600va it has transfer time of 4-8ms typically , that less than 5ms figure will be achieved rarely ,maybe 2-3 times out of 10.. and afaik as i said it depends at what point on sinecurve does the AC power is lost.. Purely luck based afaik

So the only realistic solution is to get a higher VA UPS to sustain higher inrush current with normal higher transfer times of general decent ups

The actual inrush current will vary from PSU to PSU , PC load , how much cap discharged , other things etc and cannot be ascertained without proper testing ..
All we know

1)his other psu is drawing less inrush at full load than what his UPS can handle..

2) While at low load his new psu's inrush current is within limits of his UPS , but not at high load

3) While his invertor has enough headroom to support higher inrush of PSU at full load , that is why it works fine

So this is why I was saying that there are good chances that 600 VA apc can work (""maybe"" much better threshold to power inrush, ""much"" shorter transfer time , thus ""less inrush current""

but still there is risk involved , and may not work , so make pre arrangements to return in case it doesn't work..
Cannot be determined without trying or without having proper measurements

Read the apc faq i linked previously again

Computers containing PFC (Power Factor Corrected) power supplies and their use Back-UPS and Smart-UPS SC with Step Approximated Sine waves.

They say the same thing

chimera201 said:
Now this is where you are wrong. You assume the transfer time of the iball UPS as advertised.

No , i didnt assume at all

Please read again

That 8ms figure I was taking as "hold up time" of PSU as worst case scenario at full load .. And showing how his hold up time at his pc load will easily exceed 25ms in even worst case scenario.. In reality it will be higher since his load will be slightly less than 150 watts at full load + his PSU has a higher hold up time than that.. Although it can vary a little bit from unit to unit as caps aren't exactly precise to the specs everytime

W

@gta5 I believe this is the statement you are overlooking "Similar to the start-up inrush current, there is also a surge current drawn to recharge the capacitors after short interruptions in power (Figure 8). If the power interruption was less than five ms, surge currents will typically last for half a cycle (10 ms) and will be less than 300 percent of nominal current. For interruptions of 10-15 ms, the surge current could be 700 to more than 1000 percent of nominal current, and can last for 1.0–1.5 cycles (20 ms–30 ms)."
The factor here is the time it takes for UPS to transfer power to psu & not psu holdup time.

Assuming my ups transfer time has degraded to say 10ms(after all 4-8ms is official spec) then UPS now needs to provide much higher inrush current for next 20ms which it is unable to but if it had transferred the power to psu within 8ms then it might have been able to provide lesser inrush current(still more than usual) for next 15ms or so & switchover would have been successful.

@chimera201 from what I posted above isn't it also a conclusion that using a higher VA UPS can compensate for degraded transfer time over the course of usage of UPS.

whitestar_999 said:
Assuming my ups transfer time has degraded to say 10ms(after all 4-8ms is official spec) then UPS now needs to provide much higher inrush current for next 20ms which it is unable to but if it had transferred the power to psu within 8ms then it might have been able to provide lesser inrush current(still more than usual) for next 15ms or so & switchover would have been successful.

chimera201 from what I posted above isn't it also a conclusion that using a higher VA UPS can compensate for degraded transfer time over the course of usage of UPS.

I don't think your UPS has degraded. It is working fine with your FSP PSU. But I don't trust the advertised specs by iBall. I believe the transfer time for the iball UPS to be higher than 12ms. No one is going to measure it so they can write whatever they want and they won't get sued in India. The FSP did not have any problems since it had a larger holdup.

Quote from that pdf:
"Transfer time should actually be much faster than the maximum allowable hold-up time, because the
longer the PSU goes without power, the larger the surge current it will draw when it receives power again."

Basically UPS's transfer time < PSU's holdup time (which i have been saying from the start)
In your case UPS's transfer time > PSU's holdup time.

Also no need for 5 ms transfer time. They are just saying that to be extra safe (and to make sales of course). 10ms "maximum" should suffice. Quote from the pdf again for the reason:
"However, the trend is toward shorter hold-up times. Under pressures to reduce PSU size and cost,
manufacturers are designing PSUs with smaller capacitors, which leads to shorter hold-up times."

@rakesh_sharma23 was planning on doing some UPS compatibility testing?

G

Again , ^ Please read the PDF again completely .

chimera201 said:
Basically UPS's transfer time < PSU's holdup time (which i have been saying from the start)
In your case UPS's transfer time > PSU's holdup time.

Please tell what ""realistically"" do you Assume transfer time of his UPS to be.?.

12ms (50% more than advertised or comparable apc -)

14ms ? ,

16ms ? (100% more or double than what advertsied , apc (that's a lot btw )

18ms ?

20ms?

22ms ?

Even if you assume "that high" ,
that is " still fine" ..
His Hold up time is much more >28-30ms, so highllllyyy unlikely

More than that please show some link.. For that big of an assumption

And more than that high in highly unlikely case it would be a "faulty/defective ups" not hold up time problem because that is more than enough

Quote from the pdf again for the reason:

Let me quote the exact same quote you have quoted completely

Since most IT equipment is designed for the
global market, the minimum hold-up time is 20 ms and may be longer at lighter loads.

However, the trend is toward shorter hold-up times. Under pressures to reduce PSU size and cost,
manufacturers are designing PSUs with smaller capacitors, which leads to shorter hold-up times. This
effect is somewhat offset by the prevalence of redundant power supplies, since each power supply would
be loaded to less than 50 percent of its capacity.

Note that hold-up time will be different for single- or multi-corded servers, because the more PSUs on the
IT equipment, the less power load on each PSU, and the longer the available hold-up time.

Now as mentioned previously longer transfer time of UPS will be responsible for a "high inrush current" , and may overload the UPS but that is not because PSU has low hold up time , that is because of higher inrush current of psu than UPS can handle . With same UPS another PSU with similar holdup time will work if the inrush drawn by it is well within capability of ups

Or

Another UPS with same longer transfer time of previous one but with bigger capacity will work fine with that same PSU because it can support higher inrush current within its limits without overloading

The key factor is inrush here which is dependant on transfer time of UPS , PSU design,how much cap discharged , load and other factors

W

@gta @chimera201 Let's just follow the KISS principle

These are my assumed scenarios as per my understanding of source quoted above:
1.system load 200W--CX550--power cut--ups time to transfer 10ms--CX550 caps discharging(estimated time to fully discharge 20ms)--at 10ms ups transfer power--CX550 draws much higher inrush current--UPS overloads

2.system load 200W--CX550--power cut--ups time to transfer 8ms--CX550caps discharging(estimated time to fully discharge 20ms)--at 8ms ups transfer power--CX550 draws higher inrush current(but lesser than in situation 1)--UPS works

Correct the above scenarios as per your understanding.

G

whitestar_999 said:
@gta5 I believe this is the statement you are overlooking .

where did you felt that ?

Assuming my ups transfer time has degraded to say 10ms(after all 4-8ms is official spec) then UPS now needs to provide much higher inrush current for next 20ms which it is unable to but if it had transferred the power to psu within 8ms then it might have been able to provide lesser inrush current(still more than usual) for next 15ms or so & switchover would have been successful.

Basically for a given load , the longer the transfer time of UPS , the more the Cap discharges ,
the more the cap discharged , the higher it will draw inrush current to fill it up quickly..

1)You can either get UPS with small capacity with much less transfer time so as to not allow PSU to draw a higher inrush and keep it within limits of that small capacity

Or

2) you can get a higher VA UPS with longer transfer time to support higher inrush current drawn because of longer transfer time and avoid overloading

Without proper measurements all you can do is hit and trial..

But you also have to keep in mind the design of PSU , as inrush will vary from PSU to PSU .. You can see that in that graph..

from what I posted above isn't it also a conclusion that using a higher VA UPS can compensate for degraded transfer time over the course of usage of UPS.

What you have written is right and in accordance with what they have said.. Like I just mentioned in previous paragraph

whitestar_999 said:
@gta @chimera201 Let's just follow the KISS principle These are my assumed scenarios as per my understanding of source quoted above:
1.system load 200W--CX550--power cut--ups time to transfer 10ms--CX550 caps discharging(estimated time to fully discharge 20ms)--at 10ms ups transfer power--CX550 draws much higher inrush current--UPS overloads

2.system load 200W--CX550--power cut--ups time to transfer 8ms--CX550caps discharging(estimated time to fully discharge 20ms)--at 8ms ups transfer power--CX550 draws higher inrush current(but lesser than in situation 1)--UPS works

Correct the above scenarios as per your understanding.

Yes right, second will draw less inrush current but question is how do you know that even that less inrush current drawn will be still within limits of smaller VA UPS without proper measurements/numbers and trying first ?
Maybe even the less inrush current drawn can still be higher than what your UPS can handle and if thats the case it will overload again even though inrush current was less than in situation 1

W

@gta5 I thought the source quoted talked only about UPS transfer time irrespective of load on psu so I assumed that if switchover happen within a reasonable time then higher inrush current would still be within UPS limits(aka scenario 2) which you probably didn't consider because of chance factor hence overlooked. We know that CX450 can successfully work with a 300W 6 years old UPS with a new battery & a system load higher than mine so I am assuming a CX550 with an even better 600VA/360W UPS should be fine too.

Do you guys seriously believe that iBall has a better transfer time than APC? :facepalm:

Cause: Transfer time > Holdup time
Effect : Surge

Effect comes after cause and effect won't exist without cause. CX550's holdup cannot be less than 12ms (this is a trusted value) so obviously iBall UPS's transfer time is higher than that. And each ms difference will result in an exponential increase in surge.

Also jonnyguru's post for reference:
jonnyGURU Forums - View Single Post - Facing a strange issue with Corsair CX550

Now even before gta5 quotes this part from that post:

Even a cheap Cyberpower or Tripp-Lite standby UPS has a transfer time of 4ms.

Just know that jonnyguru doesn't live in India. The cheapest stuff in western countries is still better than expensive stuff in India. Different models are sold here and there and he lives in a 60Hz grid. The APC 600VA model itself has 10ms typical(not maximum).

G

Show me 1 post where I have said his ups has better transfer time than apc and we will talk more afterwards , and no I was never going to quote jg because I had already posted even before your post , but you never read it or ignore it..

And read post 2344332 again

Corsair CX550 issue with UPS

Anyways short on time , will reply to your last post later whitestar , all the 3 sources are in front of you, form your own conclusion. The last source is much more technical and detailed .. Read again and compare yourself and see if my all posts are saying the same thing as they are saying or not

W

@chimera201 from whatever I read I understood your transfer time theory but I also have doubts regarding your 12ms holdup figure of CX550 as I understand holdup time is directly proportional to system load which in my case is never even reaching 250W so shouldn't it be ~20ms in my case.From the source you quoted my understanding is that assuming even a 20ms holdup time of CX550 & 15ms transfer time of my iball ups it is still an issue because of much higher surge current needed for switchover.Of course with APC ups with 8ms transfer time I am assuming the surge current requirement will be within the limits of UPS.Also the typical transfer time for CX series is given as 4-8ms.
*www.apc.com/salestools/VGUA-9WHCL9/VGUA-9WHCL9_R0_EN.pdf
Also in previous posts it is shown that a 6 years old v-guard 300W/600VA ups(with new batteries) is working fine with a system load more than mine(i3 3rd gen at 100% load & 7770 at 98% load) & I don't think a 6 years old v-guard ups should have a much better transfer time than my iball ups.

whitestar_999 said:
Also in previous posts it is shown that a 6 years old v-guard 300W/600VA ups(with new batteries) is working fine with a system load more than mine(i3 3rd gen at 100% load & 7770 at 98% load) & I don't think a 6 years old v-guard ups should have a much better transfer time than my iball ups.

a little correction. it is an i7 3rd gen

What my thought as I shared in one of my previous comment is that under higher load with an abrupt interruption, the output signal provided by iball UPS may be too distorted for an APFC PSU to handle even if it lasts for few milli seconds.

Also comparing v-guard with iball does not make sense to me. v-guard is one of the finest brand which produces really quality products. trust me, you will find at least one of their products in every single house in Kerala. Their quality is much superior than any other local brands available here.
the quality of internals does matter and I think iball is not able to catch up with an APFC circuitry.

W

Yes I know about V-guard(heard many good things about their voltage stabilizers). I wouldn't have put iball quality at same level as V-guard but only did that because it is 6 years old(aka 6 years old vguard quality=1 year old iball quality) but may be you are right & maybe even 1 year old iball quality is less than 6 years old V-guard quality.

whitestar_999 said:
@chimera201 from whatever I read I understood your transfer time theory but I also have doubts regarding your 12ms holdup figure of CX550 as I understand holdup time is directly proportional to system load which in my case is never even reaching 250W so shouldn't it be ~20ms in my case.From the source you quoted my understanding is that assuming even a 20ms holdup time of CX550 & 15ms transfer time of my iball ups it is still an issue because of much higher surge current needed for switchover.Of course with APC ups with 8ms transfer time I am assuming the surge current requirement will be within the limits of UPS.Also the typical transfer time for CX series is given as 4-8ms.
*www.apc.com/salestools/VGUA-9WHCL9/VGUA-9WHCL9_R0_EN.pdf

Check this specs out (also check the fine print):
*www.apc.com/salestools/JGNY-9TW79F/JGNY-9TW79F_R3_EN.pdf

BX600C-IN : 10 ms 'typical'

Also check this:
*www.apc.com/salestools/JGNY-96UETV/JGNY-96UETV_R0_EN.pdf

BE700Y-IND : 5 ms typical, 10 ms maximum
^ This costs twice.

iBall UPS : ? maximum

I'll say this again, no one is going to measure it, they can write whatever they want.

And yeah VGuard may not be better than APC but is certainly better than iBall in quality.

G

1)

Why take 250 w as system load ?

Intel Pentium G620 Sandy Bridge 2.6GHz CPU Review - Page 15 of 17 - Legit Reviews

60-65 watts for whole system with g620 + 75 watts for gpu + 40 watts for hdd ..

That's not more than 175 watts .. In reality it will likely be lower .. Since you said your gpu gets loaded 65-70% iirc , and i am not sure if madvr taxes cpu to 90-100% during video playback

550/175 * 9.9ms = 31ms hold up time in theory.. Take a few ms off for practicality

So hold up time is at least 25ms , in reality likely more because of low load . You can check the example 250 power supply hold up time graph I linked earlier

So hold up time is not the problem that is clear , And UPS having more than 22-23 ms transfer time is possible but less likely if its not faulty or defective . your actual hold up time is likely to be in the 28-30ms if your actual load is less than calculated max load..

What is your inverter, I don't think it is apc right ? And it works at full load, talking about transfer time here

G

2)

Now check this thread

Weird Power Issue [PSU/UPS]

Slight typo in 2nd case , he likely meant 3 minute backup with CM

Same issue ,

In my short on time search, I couldn't find hold up time figures of those PSU

But Seasonic in general has very good hold up times as they use big caps..
S12ii 520 also uses good sized caps

So unless there is a review showing this , I doubt that brand new seasonic there has a significantly lower hold up time than his much old CM.... both the actual hold up time would likely be atleast 20ms for his load o , so transfer time of "both" his original UPS having more than 20ms , you judge the likelihood yourself

Because the 2 UPS, both year old works good with same load with old cooler master

3)

Then look at the last poster with gtx 960 , in the end he bought an intex 1000va and works fine .. Previous one only worked at low loads or with 7770 gpu

4)

s12ii 620 working good with iball 1000va , with a 290watt system load with overclocked Sandy bridge

Looking for a Pc from 60-70k

Form your own conclusion

W

@gta5 That was a good thread but still it does not conclusively prove anything.Please bear with me & see the below points:

1.In that thread one user was successfully using S12II 520W with a 650VA APC ups with higher system load than mine.

2.In that thread GTX960 user might have issues with UPS relay as the person who replied to him said that he had the same issue & his ups used to work with psu sometimes but not at other times.

3.rijinpk CX450 works with an even lower 300W 6 years old v-guard UPS(with new batteries) which is the strongest argument against inrush current at switchover because his system load(100% 3rd gen i7+99% 7770) will definitely create a much higher inrush current demand at switchover than what his 300W ups can handle as per this theory(suggest a theory that can explain this without making extreme assumptions,I am assuming CX450 to be similar as CX550 even with GW/CWT differences)

4.May be 1000VA ups of intex/iball etc are better quality wise(being costlier after all) & have much less transfer time compared to their cheaper 600VA models.

4.Let's assume for a moment that your theory is correct then it would mean that many people using widely recommended psu here & elsewhere should be facing issue but that's not the case(aka 1050Ti/similar is more common than 1kva ups).

G

You cannot conclusively prove anything without proper measurements and some testing , all you can do is ascertain the most likely reason

1) every PSU will have a different inrush current curve this can also be seen in that graph in pdf , plus every same VA ups may not have same tolerance and can vary..

2) that other person "sometimes" working and sometimes not , means his inrush or transfer time is likley very close to the edge.. Maybe the new ups one just had marginal better transfer time or tolerance to cover "everytime"

Relay problem is less likely for 960 user because 7770 gpu was working fine, and his PSU was seasonic 520 so I seriously doubt hold up time was a problem

3) first his PSU is a different design from diff oem , with diff efficiency even and likely have diff inrush curve

second his UPS may have different tolerance for higher inrush than what your ups Can handle

Third It may have much less transfer time than yours , just an example maybe 11-12ms for him and 15-16ms for you so even though his load may be higher , assuming similar PSU design and UPS tolerance just for assumption , because his UPS switched earlier and yours late so the extra load he had may have been mostly offset by your ups switching late and that inrush is well within his UPS handling range ,

It is likely a combination of factors above

4) Or the fact that these are 1000 va UPS , "for sure" capable of handling much higher power draw than their lower counterparts and thus eliminating the issue for most cases...

4) this issue is much more common with 500-600 watt PSU I have read for those facing , generally not with 450 watt psu which most people normally havr, then most people buying 1050ti like cards have APC , and generally those buying higher gpu or 500- 600 watt psus go with 1000va UPS search around you will find some more

This is why i am saying you have good chances that an apc 600va will work mostly i am assuming because of "significantly " higher tolerance and better transfer time , but no "100%"guarantee Because of inrush , as mentioned by both apc and in that PDF ..

5) cant you arrange another apc ups or atleast any other ups to try it out ?

G

try these 2 tests with Cx 550...

""Fully charge ups batteries first"" very imp

1) you said it works fine at low load ,

you have to be as fast as possible in this test

1)run your PC at idle , with your video player , settings , file loaded etc ready ,

then cut the AC power to UPS manually , as soon as it switches to battery power , ""instantly"" play the video file , put similar load and see what happens

and
this is separate test

2) remove those 4 hdds , use only 1 OS HDD and see if that is able to take the load while playing video

W

gta5 said:
try these 2 tests with Cx 550...

""Fully charge ups batteries first"" very imp

1) you said it works fine at low load ,

you have to be as fast as possible in this test

1)run your PC at idle , with your video player , settings , file loaded etc ready ,

then cut the AC power to UPS manually , as soon as it switches to battery power , ""instantly"" play the video file , put similar load and see what happens

and
this is separate test

2) remove those 4 hdds , use only 1 OS HDD and see if that is able to take the load while playing video

Somehow forgot to did 1st test but did 2nd test & it worked.With only 1 hdd connected I started playing a video file using ~88% of my 1050Ti with cpu usage ~77% & then manually tuned off the power to UPS & then turned it back on again after few seconds,no shutdown/overload.Does using additional 3 hdd(two of which are 5900rpm) really capable of producing enough load to be the cause of this issue?

P.S. UPS is always connected to mains/inverter as PC is almost 24*7 on so I am guessing batteries are always full(except on certain days & for few hours when there is 4-5 min of power cut because of some house work resulting in removing of mains/inverter power to ups).

G

Do also the first test ," with all 4 hdds connected"

Also can you do 2nd test again with 1 hdd? This time do it 10 times ( won't take much time ) ( simply on and off AC power manually 10 times while your PC is playing video file just give a gap of 30 seconds between each set of switch off and on..

So play video , after removing 3 hdd ,
Then switch AC off , 2 sec gap then AC on

Give a gap of 20-30 seconds

Then again AC off and turn it on again after 2 seconds..

Wait 20-30 seconds

Again switch off AC , 2 sec gap and then on again.

See how many times out of 10 does it work..

Yeah if its always connected with very less power cuts , then batteries would be fully charged

W

Well I did turn off & on AC power to ups 4-5 times with a gap of 10-50 seconds between each attempt(that lasted 2-3 seconds). I will be able to do the 1st test tomorrow only as system is now running with fsp.

P.S. in 1st test how fast is "instantly" because no matter what I don't think I will be able to play the file before 2 seconds after hitting play button in player.

G

Yeah as fast as you can ... 2-3 sec is fine

For the next separate test , you can try adding 1 hdd at a time and test with that 4-5 times to find the max load/limit of hdds that will be supported by your UPS

W

^^Will do but what how much load 3 hdd can offer anyway & what exactly will be proved by this experiment if it turns out to be correct(aka 1 hdd no issue,4 hdd issue).

W

gta5 said:
Yeah as fast as you can ... 2-3 sec is fine

For the next separate test , you can try adding 1 hdd at a time and test with that 4-5 times to find the max load/limit of hdds that will be supported by your UPS

I did the 1st test with CX550 & strangely everything is working fine now!I connected all HDDs then turned off power to UPS & immediately start playing video file with no issue(tried this 4-5 times). Then I tried my initial test by switching off power to UPS while playing video file & this time everything worked as it should.I will update on this after 1-2 days of usage but as of now it looks like everything should be fine.

The only thing I can notice about current situation is that mains AC supply is steady with no voltage fluctuations(aka no voltage regulation by inverter).

G

It appears that the inrush drawn is very close to edge of your UPS capacity.. So sometimes it is working and sometimes not ( varying transfer time thus varying inrush in accordance with load , depending upon at which point on sinecurve you are loosing AC- luck based ) and your PSU is fine and hasn't degraded..

Correct me if I am wrong , but your initial posts gave the impression that you were assuming your fsp to be non-apfc.. It is actually an APFC PSU..

W

So assuming this to be the case is it fine to get a 600VA APC ups in future as its transfer time will definitely be much better than my current ups.

You are right,I just never thought that a 2011 psu would have apfc!

S

gta5 said:
It appears that the inrush drawn is very close to edge of your UPS capacity

Bro. I read the APC link you posted on page 1. So as per the formula on the link - " PFC power supply’s rated output power and multiplying it by 1.25" -

Seasonic s2 520 should draw 480*1.25 = 600W. But if the PC "Load" wattage is 275 watt only, then will the PSU still exceed its rated max power because of inrush current?

please read about my config and power calculation on my thread - Config for 3d Modelling + Rendering.

I would like to save money by buying a 650va ups if that is sufficient.