Picking the right UPS for me

[progmars_apc]

Hi all.

I'm looking for a reliable UPS for my Intel i3 based PC and 23" LCD monitor. I live in rural area where there are often short blackouts (almost each day, for 10 seconds or more) and brownouts. I'm a bit confused about Back-UPS and Smart-UPS differences.

At first I thought that all Back-UPS are offline (stand-by) UPS, as opposed to line interactive, but it seems I'm wrong, and there are Back-UPS with line interactive topology, although sometimes this is not clear from the model number. There are mysterious RS, BR, GS, ES postfixes which determine whether the UPS is stand-by or line interactive and whether it has AVR transformer or not. I guess, for my case with multiple brownouts I should pick a line interactive UPS with AVR to benefit from the transformer, right? But these brownouts usually are so short - just a second or so, thus I'm not sure.

One friend recommended to think about the cases when I would want to provide backup power to some device which requires true sine wave - like a radio or maybe a PC with active PFC PSU, which get more common nowadays. This means that I should pick a Smart-UPS because only they provide true sine. But I got a surprise again - there are some Smart-UPSes which do not provide true sine output! As I understand, these UPSes are marked with SC - I've no idea what does it mean.

Thus I have some questions.

1) If we ignore backup power differences for a moment, and look at the Smart-UPS with SC model number like APC SC620I which does not provide true sine output, then in what way is it better than Back-UPS Pro BR550GI ? Will I benefit from Smart-UPS with SC in any way or BR550GI is almost the same thing?

2) It seems, if I would like to go for true sine output for my home, I have only one choice: APC SMT750I . But this one seems a bit too modern with all that flashy LCD screen and whatnot. The LCD and those programming button features make it more expensive and maybe a bit less reliable. The more electronic parts a device contains, the greater the risk of something going bad. Is there any cheaper APC Smart-UPS with true sine output and more old-fashioned controls, without that LCD etc.?

3) I have used to connect all my devices to a power strip with a master switch. At the evening I turn my devices off and switch off the power strip to conserve electricity and also to be safe in case there is a storm at night - I don't want my devices to get zapped by a thunderstorm. But how will UPS behave if I turn it off each night? Won't it make the battery lose some of its charge during the night thus shortening battery life? Or is this not that important at all?

---------------------------------------------------------

The long story follows.

Till now, I have tried multiple UPSes, and I think they have saved the life of my PC hard drives. While my neighbors who do not use UPS have complained about dead hard drives, I haven't had a hard drive problems for the last 10 years since I started using UPS. But for unknown reason, all the UPSes I've tried do not live long enough - I haven't even had a chance to replace batteries!

At first I had ICUTE-530 from PowerCom. It died in one week - suddenly it shut down my old Pentium 3 PC and started emitting signals which were not described in the user manual. Returned to the shop, they replaced it with some Mustek. Well, I guess, that was a downgrade, but still it served me well for 5 years. And one day it suddenly died and could not be turned on. I thought that maybe the battery is dead, but the UPS itself also did not emit any signals at all. It should signal something when attached to the mains, even with the battery dead, right? So I replaced it with PowerCom IMD-825AP. This one worked fine for almost entire warranty period (two years), but then one day it suddenly lit up OVERLOAD indicator and immediately turned off itself and also turned off my PC. There's no way of overloading this 825VA (495W) UPS, my PC together with the monitor consumes less than 300W. I read that some UPSes react this way when the battery is dead or close to that - the UPS might get confused and show OVERLOAD instead of BAD BATTERY, or maybe show both signals together. I immediately disconnected my PC from the UPS and then turned the UPS on without any load at all. Still, it showed OVERLOAD again and turned off immediately. Then I left it to stay. Next day I turned the UPS on and this time it seemed working fine. I connected a 60W lamp to the UPS and tested the battery with voltmeter and it showed steady 12.7V, slowly going down to 11.2V during 30 minutes. After that, the UPS signaled that the battery is low, I connected it back to the mains and UPS charged the battery and now seems to be working fine. I guess, this means that the battery is not dead. But what confuses me is that I don't see the float voltage of 13.8V being applied to the battery when the UPS is charging it. The voltage just slowly (in two hours or so) rises back from 11.2V to 13.2V, and does not go higher. Shouldn't there be steady float charge voltage (at least 13.5V) applied to the battery always while the UPS is connected to the mains? Maybe the charging circuit of my UPS has gone bad.

Now I'm afraid to use my UPS. If it failed once with that nasty false OVERLOAD, it might do it again. I was thinking to return it to the shop for warranty service, but I'm afraid that they won't find anything wrong with it - it seems to be working fine now, after all! Maybe this OVERLOAD glitch happens occasionally - this means that my UPS is not reliable anymore and I'll have to find a new one.

[BillP · Accepted solution]

Hello,

I asked one of our EMEA support teams to help provide some comments/feedback for you since I am based in NAM.

1) If we ignore backup power differences for a moment, and look at the Smart-UPS with SC model number like APC SC620I which does not provide true sine output, then in what way is it better than Back-UPS Pro BR550GI ? Will I benefit from Smart-UPS with SC in any way or BR550GI is almost the same thing?

Please find short summary of differences between those models

“SC” vs. “BR” model

SC620I – line interactive topology, older design model,  on the market ~10 years already.

http://www.apc.com/products/resource/include/techspec_index.cfm?base_sku=SC620I&total_watts=50

Pros:  Still not expensive~230 Euro, Automatic Voltage Regulator, data line surge protection,

Cons: Low Output Power factor – 0.6:  390 Watts/620 VA, Stepped approximation to a sine wave output, 2 yrs warranty, grey colour design

BR550GI - line interactive topology, latest Back UPS generation model.

http://www.apc.com/products/resource/include/techspec_index.cfm?base_sku=BR550GI&total_watts=200

Pros:  Cheap ~150 Euro, Automatic Voltage Regulator, data line surge protection,  LCD – intuitive settings adjustment, more outlets than “SC” unit, nice design, 3 years warranty for EU countries

Cons: Low Output Power factor – 0.6:  330Watts/550 VA, Stepped approximation to a sinewave output

2) It seems, if I would like to go for true sine output for my home, I have only one choice: APC SMT750I . But this one seems a bit too modern with all that flashy LCD screen and whatnot. The LCD and those programming button features make it more expensive and maybe a bit less reliable. The more electronic parts a device contains, the greater the risk of something going bad. Is there any cheaper APC Smart-UPS with true sine output and more old-fashioned controls, without that LCD etc.?

Most of our new generation UPSes already have build in display. I would recommend one of the Smart UPS, since these are more intelligent, efficient UPSes with  pure sine wave output, LCD does not have any negative impact on the UPS reliability or efficiency (new SMT design models are actually more efficient  than previous SUA with LED panel). It has also many advanced features( AVR transforer, Controllable Outlet bank, Smart-Slot for Accessory Card, ~0.7 Power factor with more battery capacity, 3 yrs warranty, Predictive battery replacement date, Built-in energy meter, Improved diagnostics and logs, Switched load group for non-critical load shedding, independent reboot and sequenced on/off ).

If you are looking for bit cheaper Smart UPS, please consider one of the "SMC" model which has less features ( no smart slot, 0.6 power factor, 2 yrs warranty, standard outlets)

3) I have used to connect all my devices to a power strip with a master switch. At the evening I turn my devices off and switch off the power strip to conserve electricity and also to be safe in case there is a storm at night - I don't want my devices to get zapped by a thunderstorm. But how will UPS behave if I turn it off each night? Won't it make the battery lose some of its charge during the night thus shortening battery life? Or is this not that important at all?

The ideal mode is to have UPS powered on all the time, however I don't see any problem with turning it off every time, voltage drop overnight  will be negligible.

My personal opinion on this last question is too to just leave the UPS on all of the time. It is designed to remain on and even when the UPS is connected to AC power, it should continue charging even though the UPS output is off.

Hope this helps. We can hook you up with someone from local support if you need further details that we can't provide here for some reason.

[progmars_apc]

Hi Angela,

Thank you for the useful information, that was really helpful.

So, the conclusions are that it's not worth to invest in SC series "almost smart" UPS (e.g. SC620I ) because new Back-UPS PRO models provide almost the same features or even more.

And if I decide to "go smart", then I can pick between SMC or SMT models. There is just one caveat - while on Amazon SMC is indeed cheaper than SMT, in my country (Latvia) in almost all shops for some weird reason SMT is cheaper than SMC (comparing SMT1000I and SMC1000I) As Amazon won't deliver an UPS to Latvia because of hazardous materials, I'll have to buy SMT in a local shop.

Still, if I go for 750VA power (which currently is enough for my system), my only choice is SMT750I because there are no SMC UPSes with 750VA.

This leaves me with two choices to consider - BR550GI or twice as expensive (but so much better) SMT750I. Now I'll just to have to do some budget planning to see if I can wait some time and save some money for SMT750I.

Thanks and regards,

Martin

[BillP]

I am glad we could answer your questions. Let me know if you need anything else.