Looking for the cheapest silent-when-idle UPS with pure sine output for power consumption below 400W

[progmars_apc]

I'm looking for the cheapest (but still reliable for many years) UPS to support my APFC power supply which is rated 620W. I measured the real load of my PC and monitor under 3D stress test and it was under 300W.  So, I guess an UPS that provides 400 - 500W should be plenty for me... but only if it supports true sine output when on battery, because I've read that for APFC you need true sine OR a beefy UPS with 1000W.

Another thing is that I would like the UPS to be silent when it's idle. A built-in fan is very welcome to avoid overheating of the internal components BUT only if it turns completely off when the UPS is not in battery mode.

I'm browsing the APC models available in Europe and I'm sad. True sine seems to be offered only for the more powerful models with 1000VA, which I don't actually need - I just want a minute or two to properly shut down my computer (ideally - through Windows USB battery management setting). Am I missing something?

I'm getting desperate. I have tried some competitor models and while there are some cheaper true-sine options with solid USB HID battery management, the models with a fan seem to be suffering from "dumb" fan speed management and noisily pumping cold air through them when idle.

Is there any solution to this?

[BillP]

Hi Martin

From your post, I would recommend the SMT750I or SMT750IC (this one has the new smart connect features). It is pure sine wave, 750VA / 500W and it is virtually silent (I have one sitting on my desk). It is compatible with our Powerchute software for shutdown and other management feature, and as I said the SMT750IC has the smart connect port for remote monitoring features (see https://smartconnect.apc.com/welcome)

I hope this help with your search

Regards

Matt

[progmars_apc]

Thanks for suggestions. SMT750I looks good although very expensive. It's a shame that there are no "non-smart" (I don't want to pay for the features I don't really need) cheaper models with pure sine output.

I found a model from a competitor company but that, in turn, is not silent. Sigh.

Some rant. Compromises, compromises... when will companies stop competing and work together to create the best feature/quality/price devices for different price ranges? Probably never - that's the curse of modern economy. Only programmers seem to get it right and create open-source products that improve through collaboration and not patents and secret "know-how"..  Commercial secrets usually mean that every company goes through the same mistakes as their competitors, until they get it right but their customers have to experience all that painful process on their skins.

[BillP]

Hi Martin

We are bringing out a range of Pure Sine Wave Back UPS but they won't be available until sometime next year. 

Regards

Matt

[progmars_apc · Accepted solution]

That's great news! I really hope APC will do it right and create silent, affordable UPSes for APFC systems, which means almost every modern PC.

Also, it would be nice to have them in metal casing because accidents do happen and plastic is not a safe choice for possibly overheating devices. I've seen a few reports about really bad plastic smell of BackUPS plastic UPSes on Amazon and elsewhere, and some people were even forced to return them.

Meanwhile, I guess I'll follow your suggestion and get SMT750I.

The only thing that bothers me about SMT750I is some disturbing reviews and reports about it being unable to stop charging the battery even in case of overheating (not just for old but also for brand new batteries). For example this one:

https://forums.apc.com/spaces/5/smart-ups-symmetra-lx-rm/forums/general/12220/is-there-anyway-this-n...

From that thread I might assume this issue was resolved in latest batches of SMT750 and firmware, and also we could safeguard it more by tweaking temperature alert settings, but I'm not fully sure.

Also this one:

https://broadcastengineering.info/viewtopic.php?t=5888

where some people say that they have switched from APC to competing companies because of bulging batteries problem in APC smart units.

Is SMT750 able to detect overheating not only at the location of its electronics parts but also at the battery location and stop charging immediately and not attempt to charge again until the battery is replaced?

Or would it work like this - UPS attempts to charge the battery, detects overheating, cools down, and then attempts to charge again, thus potentially causing the battery to bulge and leak more and more until somebody comes and manually turns the UPS completely off?

I looked in the user manual:

http://www.apc.com/salestools/SCON-7NBSEM/SCON-7NBSEM_R9_EN.pdf

but the only place where I could find the word "heat" was:

"Over charging, over heating or other misuse of batteries can result in a discharge of battery electrolyte."

There's nothing mentioned about how the UPS itself manages to not overcharge or overheat the batteries.

If there was some hardware improvements in the latest SMT batches, how do I make sure that I buy the latest improved unit and not some older "unsafe" unit? Are there any distinction signs for the new units?

If I manually set the critical temperature to be lower in PowerChute, will it turn the UPS completely off (including also the battery charging electronic components - because I've seen some UPSes continue charging even when off, as long as they are connected to the power) and don't attempt to charge again until I manually fix the temperature issue and power it on? I definitely don't want it to start going into some kind of 'attempt to charge - wow, it's too hot - cool down - attempt to charge - wow, it's too hot - ...' in my apartment while I'm away and can't do anything to turn it off before it starts emitting chemical smells through entire house.