Overload problem with an old UPS

[Anonymous user]

I have APC BACK-UPS RS 1500VA 230V which supports 865 watts tops. I have bought it 5 years ago. Let me explain my problem.

I have a APC voltage regulator behind of my ups. During sudden voltage drops, it gets triggered and voltage is tipped a little higher. It also causes my UPS to goes into battery mode for a second or two. Thats no problem.
After 5 years of service, during these on/off battery switches, my UPS started give me overload error light with complete shut down of entire system . My load is usually 450-550 watts by the way. First i thought batteries are failing after 5 years, after that i removed the batteries, i looked into their model, and i bought the same brand/model batteries (not official battery pack from APC but the same batteries the official battery pack uses :D) . I connected those new batteries. It solved the overload fail during 1-2 second interventions. But it didnt solve the problem when i completely switch off the power.
So i unplug the power cord of ups it should stay on for couple minutes at least. It does stay on when the load is below 350 watts but it suddenly fails i unplug the cord when the load is over 400 or 500 watts. So i thought it cant support up those upper watts but i tried this. I completely shutdown everything i unplugged ups cord from the grid. I started everything on battery. Systems are loaded and i pushed the UPS up to 700-750 watts without any fails, no overloads or anything.
What i learned from this experiment is, i think ups cant intervene fast enough or back up heavy loads quickly enough. Or there is something wrong with UPS or new batteries. I was thinking to buy or build APC BR24BP BACK-UPS battery pack extension of this UPS, could this solve my problem or the life of my UPS is just expired or any other thoughts?

ps. I have PowerChute installed i monitor all the activities on there

[voidstar_apc · Accepted solution]

>
Or there is something wrong with UPS or new batteries. I was thinking to buy or build APC BR24BP BACK-UPS battery pack extension of this UPS, could this solve my problem or the life of my UPS is just expired or any other thoughts?
>

That's some good sleuthing.

I don't know how likely it is that the UPS is taking longer to transfer; would seem odd after only five years. You might try [changing the sensitivity setting to low|http://www.apcmedia.com/salestools/ASTE-6Z7V72_R0_EN.pdf] to reduce this, though it would also increase unnecessary UPS interventions.

Another possibility is the load on the UPS has changed. For example, as a computer's power supply ages, it becomes less capable of handling momentary power interruptions. Some react to loss of power by attempting to draw as much current as possible.

How did you adjust the load on the UPS when you were testing?

Also, you probably already know this: the manual indicates that the RS UPS has +/- 12% boost and trim. So using a voltage regulator seems a bit redundant.

[Anonymous user · Accepted solution]

Jokes on you 😄

I have 3 monitors, one overclocked cpu core i7 930, one HD5970 and one 1 gtx8800 gpu that draw much of total power. My psu is xilence 1200watt model and i cant say that it's old. I never use that much of power, i know that 800 watt is not enough when i overclock everything on the system. I increase the load by stress testing the components using Prime95 or furmark
I just tried these things recently
If i load the system by stressing cpu and keeping the load around 500- 550watts, UPS can manage the power loss.
If i load the system by stressing gpu, even the load is around 450 watts, UPS cant manage the power loss.
Maybe gpu units are very susceptible to power interventions and like you said psu unit may try to draw as much as power like 1200 watts from UPS which causes overload

I know changing sensitivity setting to low would cancel those unnecessary interventions, i tried that but im not sure those interventions are unnecessery or not.
Regular voltage should be 220V here but it drops as low as 160V in here. UPS cant manage voltages under 188V, that's why i need a regulator

I do cpu computing as well as gpu computing for scientific purposes. It seems new batteries solved the problem for cpu computing part but not gpu computing. I will build external battery pack anyway, this will triple the current capacity, maybe this will solve the problem.

[Anonymous user · Accepted solution]

I tried couple of things i want to take advice from you

1. I built (home-made) ups cables and connections. I connected 2 batteries to the front and 2 of them to the back. Powerchute still shows 2 battery of remaining time. (2 batteries mean 2 X 12V 9ah batteries)
2. So i thought maybe there is a connection problem. I took front batteries out and tested then i took back batteries out and tested front batteries. In both cases it shows only 2 battery of remaining time.
3. Then i connected 4 batteries together up front (2 serial 2 parallel to achieve 24V). It still showed 2 battery of time.

while 4 batteries connected (2serial 2 parallel). I read 450 watts of load and 13 mins of remaning battery life. So i decided to measure real remaning time. I disconnected the telecommunication port and cut off power. Then I measured 22 minutes. Which is quite acceptable because 2 of the batteries are brand new and the other 2 were 5 years old.

But still with these new combination, my ups still cant intervene (start to transfer juice) fast enough on heavy loads like 600 watts. So buying another pair of batteries shouldn't solve my problem.

1.Buying an online ups would definitely solve my problem (this one is line interactive). But is there anything else i could do before that?
2.How come powerchute display remaning time incorrectly? I connected those batteries to the back like a battery pack. It should at least triple the remaning time if it was real battery pack (APC BR24BP). Is there a chip or something to tell which is connected or not?