PermaLink Is "Quiet Online Uninterruptible Power Supply (UPS)" an Oxymoron?03/23/2006 02:59 PM
In the quest to replace an APC SmartUPS that has a "feature" of shutting power off to its load without warning if the battery dies (confirmed w/ their tech support), I've been looking for a better replacement UPS which is needed for Boston's great summer brownouts.  An "Online" (a.k.a., "Double Conversion") UPS runs off battery all the time and produces a non-interrupted sine wave power signal so your systems have no chance of getting a power glitch; unfortunately, this also means the UPS fan is on all the time (as opposed to the SmartUPS which only turns on its fan if power is lost or it's at 90% max load). My criteria was:
- USB management port
- hotswap battery
- multiple load segments so the UPS can shut down "non-essential" plugs to conserve power
- runs in bypass mode and acts like a surge protector when the battery needs replacement
- extendable runtime by plugging in external battery modules
- Linux support via nut
- reasonable 40lb weight for a 1000VA unit for 20min runtime at half load

The TrippLite SU1000RTXL2Ua is bloody louder than my dual processor desktop w/ screaming SCSI drives (and TrippLite support sucks because I asked them how loud it was before buying it and they never answered so now I'm stuck w/ an RMA fee and shipping costs).  At least APC publishes their 45dbA noise level for their SmartUPS RT 1500VA.  The Powerware 9210 has environmental noise of 48 dbA.

These manufacturers need to look at the quiet PC crowd for fans that work.  The TrippLite uses a Delta fan which is used by overclockers for pushing a lot of air around, but it's also well known to sound like a jet engine.  Quiet PCs are using 120mm fans at low RPM to maintain good air movement at quiet sound levels.  I wish I could find a UPS that did the same.  Looks like I'm back to using a line-interactive UPS unless someone out there knows of a quiet on-line UPS :-P

Comments :v

1. Gabriel Heiser10/11/2015 03:57:32

I just swapped out the two very noisy fans in my Tripp Lite SmartOnline SU1000RTXL2Ua unit. The original fans are Delta AFB0812SH, and I replaced the hidden internal fan with an 80mm Noctua NFR-8 and the other fan (near the back, covered with a small grate) with a 120mm Noctua NF-P12. To use the larger fan at the back, I purchased a $6 shroud that converted the size to fit the 80 mm holes; I then used a bit of silicone to plug the gaps around the shroud.

I had to attach the fans (which come with four wires) to the two-wire plugs of the originals, so I just soldered red to red, black to black. The small Noctua has no red wire, but I found out that the yellow wire is the one to connect to the red of the plug.

All fired up immediately, with a HUGE drop in noise! Well worth the effort. I believe the CFM of the 80mm and 120mm fans combined will be sufficient to keep the UPS cool enough, but do your own research!

2. ken04/30/2014 23:13:22

@N8N: thanks for the pinout...if I had known, I might not have sent it back

@peash: yes, you can use it to run a room fan...if you connect it to high voltage stuff like hair dryers, it'll drain really fast though

@paul: I've daisy chained UPSes to increase runtime, but not in the manner you describe. Just get a good sine wave UPS (e.g., Eaton or TrippLite or APC) and you'll be fine

3. ThankfulJoeSixpack04/17/2014 03:36:37

Thanks for the pinout N8N! After looking around and googling, your comment was the only one I found that had specifically addressed the wire order. Hoping that (And I'm pretty confident that it will be) it is the same on my Tripp Lite SU1000XLA Online UPS, as it uses the same fan and connector!

I'm literally using the same parts as well. A Noctura 80mm and a Noise Magic NMT 3. Again, thanks to you.

I really like the UPS otherwise. I'm generally a fan of Tripp Lite's stuff for humble hobbyist applications. If I can just get the fan noise down from a constant house wide roar (literally) to a normal hum, I will be satisfied.

4. N8N04/07/2014 16:52:08

To connect standard PC fan to Tripp-Lite UPS - red to red, black to black, yellow to blue. Done. Quiet.

5. N8N04/07/2014 15:57:16

I have a Tripp-Lite SU1000RTXL2Ua that I've modded with a Noctua NF-R8 80mm fan and a Noise Magic NMT-3. It's now damn near silent and still seems to run cool. I wouldn't run it at full load as the Noctua fan will push less CFM than the stock Delta fan but for keeping my stuff up and running through short brownouts it's great.

There is one special instruction, you need to cut the connector off the stock fan and splice it to a fan extension power cable to make this work because the connector and pinout on the Tripp-Lite unit will not work with a standard 3-pin fan.

You also cannot unplug the fan as the Tripp-Lite unit supervises the fan.

I'll post back in a few, I forgot to document the pinout for the fan when I did mine, I'm actually building another one for a friend and was searching for the pinout when I found this thread. I will just pop the top on my old one because I'm not finding where I posted it.

6. peash07/22/2010 08:05:58
Homepage: http://nothing

i was wondering if i can run a room fan by an UPS

7. paul02/21/2009 16:23:38

is it possible to have the output of one UPS connected to the input of another UPS and then the output of the second UPS connected back as an input to the first? to mantain a steady supply disconnectedfrom main

8. ken06/04/2008 00:47:21

I think that's probably transformer hum. I get a little of it on my SmartUPS but it's not that noticable unless it's under load when the fan fires up as well.
The BackUPS line is just crap...try this simple test: connect the BackUPS w/ just a room fan on it to a wall outlet; connect an air conditioner to the same wall outlet. Fire up the fan, then the A/C and watch the BackUPS just shut down. It doesn't handle this brownout simulation well at all. This was tested w/ a Backups 350 which should have had plenty of power for a room fan.

9. NEIL Fiertel06/03/2008 20:18:44

I hear a high pitch oscillator whistle from several of my APC UPS units including a BX 900 CN. I contacted the on line chat and was told it was defective..I do not believe this to be the case as it otherwise works perfectly when power is cut and so forth including the start with battery check..It is not overloaded in the least...I hear this 10K HZ or maybe higher pitch coming from the unit..very is annoying to hear and wonder if there is a cure for it. I presume it is the switching power supply that delivers constant AC to the units attached. I hear it with or without a load and with or without it being powered by the mains. I do not hear it when it is shut down and still attached to mains power. Any suggestions on this? Please contact me at my email at for advice. I would be appreciative.

10. Jean05/16/2007 19:43:44

I have a powerware 9120 3000VA and have changed the batteries twice in about a year and half and about to change the third. I am wondering if i could replace the cells with car batteries for a longer backup time. Any ideas ( It has 8 x 12 7AH battery in it) Thank you

11. Ken Yee05/13/2007 02:56:57

Stephen, IIRC, the Tripplite uses relatively small 60mm fans (I opened it up to see what was involved w/ replacing the fans). You can probably replace them w/ thermally controlled quiet fans, but I'm not sure how much quieter you can get w/ relatively small 60mm fans. In the end, I thought the Tripplite was too heavy as well, so I returned it (shipping was $80 and I got it w/ a 10% return charge!).

12. Stephen05/12/2007 15:03:26

I made the mistake of getting a tripplite SmartOnline Expandable 2U Rack/Tower UPS System SU1500RTXL2Ua and as soon as I heard that fan noise knew it was a mistake.

I needed an online system because the power at my apartment is horrendous. I already have a line interactive, but small power dips make it through the line interactive backup and slowly eat my computers power supply and damaging components.

I've been through one computer and my second one is beginning to behave badly.

I had emailed Tripplite before purchasing about fan noise, of course they never responded and of course I responded without getting an answer and bought one online.

Can I unplug the fan? Can I replace the fan with an Arctic Cooling fan? Or should I just bite the bullet and send it back?

Thank you.

13. Ken Yee05/19/2006 22:46:19

Quick update on the fan modification to the Powerware 9120. I ended up using an Artic Cooling Pro TC. The Powerware is now so quiet I can't even tell it's on unless I look at it

The Artic Pro TC is a thermally controlled fan that will push from 12-32 CFM depending on the temperature. The Artic Fan 8's sound-reducing cage was too big to fit because there's only enough space for a standard depth fan. I had to splice the wires from the old Powerware 2-pin connector to the new fan (and ignored the RPM wire on the Artic fan).

UPS makers should just use standard PC fan connectors for their fans so it's easier to plug in replacements and it might save them money with the large number of PC fans that are produced.

BTW, Powerware has a great RMA policy (the scratch n' dent Powerware 9120 I bought died after a few weeks w/ a "low output voltage" error...another reason for a useful LCD display). They'll overnight you a replacement UPS and you can just pack your old one into the box with the prepaid FedEx Ground shipping label. I got to check out a 9125 1500VA when they sent me the wrong one; it has twin 80mm fans, but it's quieter than the 9120 because the fans seem to be speed controlled by the UPS (they spin up to full speed initially, then drop back to a much lower speed when there's not much load). Apparently, they didn't have any 9120's in stock, so they sent a 9125 temporarily until they could get me a replacement 9120. Needless to say, I'll be recommending Powerware instead of APC or Tripplite to my customers from now on

14. Ken Yee04/11/2006 23:15:47

Quick tip on getting the Powerware to work w/ - it uses the bcmxcp driver. You can use the serial port version or you can use the bcmxcp_usb USB (be sure to use nut 2.04 or greater or you'll get complaints that it can't find a Powerware UPS) port driver with the USB port set to "auto" and nut will look on all USB ports for the Powerware.

The only thing it doesn't let you control is the load segments (looks like only the MGE ones support that), but it does let you get the ambient temperature in addition to runtimes and load info that you can get off the front panel. Now my server can shut down cleanly when we have a power outage

15. Ken Yee04/05/2006 00:07:52

Continuing my quest, I bought a Powerware 9120 1000VA. It's rated at 45dbA and it's actually quiet enough for a living room HTPC. Not silent, but not jet engine whine like the idiot Tripplite SmartOnline design

The fan it uses is a NMB 3110KL-04W-B50 which is an 80x80x25mm fan using .30A to output 39CFM at 34dbA (2 wire, so no worry that the Powerware is monitoring RPM). The amount of cooling is probably overkill, so it can probably be replaced with an Artic Pro TC or Artic Fan 8 which have roughly 28-30CFM at only 21dBA.

The LCD display on the Powerware is actually useful so kudos to them for doing a good job on it. It displays the input/output voltage, frequency, %max load, load wattage, and battery runtime at load. This info is a lot more than either APC or Tripplite provide. Powerware is going to get my recommendation when customers ask about UPSes.

16. Alexander Scoble03/28/2006 22:34:22

As far as I can tell, it has a fan because the units are built to run in switch closets and other enclosed spaces with poor ventilation.

As long as you keep the unit well ventilated in a relatively cool environment and don't let it run on battery power much, a fan is not needed.

Also, you will have problems installing an aftermarket fan in the units as they seem to use smaller 3 prong connectors than most PC fans use. You would have to cut the connector off of an aftermarket fan and crimp the proper connector onto the bare wires.

17. Ken Yee03/25/2006 00:08:52

I'm amazed you can disable the fan and it doesn't burn out; you'd think that they put such a high speed fan in there because of heat issues or they would have put a lower speed fan in. You might want to put a big slow 120mm fan at the opening to get some air circulation through it.

I returned the TrippLite already (they didn't respond to any of my emails over the past few days about the fan noise so I figured I wouldn't want to deal w/ a company with such sorry customer support anyways) so I'm out $150 in RMA and shipping fees (youch..I could have bought a simpler line-interactive UPS for this learning experience).

I might look at another online UPS and replace the fan with a temperature controlled one instead...I'm just a glutton for punishment...

18. Alexander Scoble03/24/2006 19:03:39

Hi Ken,

Found your blog after you left a comment on my Computerworld blog.

I did in fact end up getting an older non-USB Tripplite online UPS. And yes, the fan was loud. So I simply disconnected it. Since the UPS gets plenty of ventilation in my home theater, it gets warm but that's about it. And of course, now makes no noise.

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Full-stack developer (consultant) working with .Net, Java, Android, Javascript (jQuery, Meteor.js, AngularJS), Lotus Domino