Hi All,  

 

Ive read quite a few posts regarding UPS but would appreciate a few peoples recommendations on the best ups for a low draw system. it needs to provide data to the unraid system etc.

 

Thanks

Define "low draw system".  What is it that you want this UPS to do?  (Long term server uptime during outage or just shut server after a couple of minutes?)  How often do you experience power outages?  What is their duration? 

Edited October 28, 20196 yr by Frank1940

I bought an APC 650 (BNM650M1) about 9 months ago. It provides a USB interface

to UNRAID which has worked well using the built in configuration without any fussing.

The server draws about 21-25 watts when idling, ramps to about 85 watts at full bore.

The battery time is limited, but so far all AC power outages been about one second

(about 12 outages / glitches in 9 months).  Unit can be purchases on-line, our local Staples

has it in stock about the same price.

 

UPSStatus   BatteryCharge   RuntimeLeft   NominalPower   UPSLoad   UPS Load %

Online   100.0Percent   98.2Minutes   360Watts   25Watts   7.0Percent

 

-- Tom

 

Thanks Tom,  Ill look at that one,

 

Frank,

 

Its quite hard to guess power draw as I havent built it yet  im going to say its similar to the values tom quoted maybe slightly less.

 

We get quite a few 5-10 times a year very small power outages and a few longer up to 5 mins however sometimes this trips our electric and its off till I flip the trip switch.

 

In the small cases i just want it to be protected when it fails I want it to run for 5-10 minutes advising me via email etc that power has been lost and that it will shut down in x mins.  Obv i will have to run the modem router off the UPS aswell and probably the POE cctv switch for as long as it can once server is down  so we are probably talking 70-150w  load max, id suspect towards the lower range.

If you want 10 minutes of runtime, you need to spec at least 20 minutes of advertised capacity at the draw you anticipate. The types of batteries used generally don't like being run down below 50%, so if you want to keep the UPS healthy for as long as possible you need to limit the amount of power you pull out of it.

 

Sounds to me like you would be better off with a mid sized UPS, something around 1000VA. The APC BR1000G is rated for 24 minutes at 200 watts, which is probably a good real world estimate for your rig + router +switch + modem.

 

Keep in mind that shutting down unraid brings the power draw to the absolute upper limit of any system, as it has to spin up all drives to properly unmount them, and high cpu load as all the running services are issued the shutdown commands.

Ive seen a slightly smaller one for about £90

 

APC Back-UPS 950VA 230V AVR IEC Sockets APBX950UI

 

the 1000VA seem to step up in price a bit.

 

4 minutes ago, Smoothe said:

the 1000VA seem to step up in price a bit.

Probably because the runtime at a specific load is double. The BX950UI probably doesn't have the runtime to 50% to get the system fully shut down. 200W load = 10 minutes, so 5 minutes max to keep from overly depleting the batteries. You would need to start shutdown pretty much immediately to keep from running it down. (Depending on actual load, of course.)

 

hmm too tight i think,  the next one up is  BX1400UI its not too much more but may be worth it.  Im also considering getting something to measure power but the price of that once you take it into account means i probably should just spend more in first place

The "Kill-A-Watt" meters aren't that expensive. And they are all around useful, not just your tech stuff.

 

I think you need to build out your system to your requirements, then measure the need, and buy based on that, rather than shopping for the UPS at the same time. If you end up not needing the power, too large of a UPS is wasteful as well.

 

You have capacity and time, neither of which you can quantify right now. It's easy to measure the draw with a meter, and you can time your shutdown routine to some accuracy once you figure out what all dockers and VM's you will use. Until you get numbers, it's all pretty much speculation.

Biggest problem with the larger capacity UPS's is that the batteries are often non-standard or they are a battery pack of two batteries in a proprietary configuration.  The batteries are only good for 2-5 years-- depending on environment and usage pattern.

 

I have one large capacity UPS and one normal one.   When I have to replace that larger one, it will be a normal one.  Now, let me explain my experience.  In my area, I have observed that there are two types of power ages-- Short ones of less than ten seconds and long ones that last a minimum of two hours.  We get about an outage a month of the short type.  The long ones are random events...  Like a drunk hits a power pole. Or an oversize load hits an armored cable carrying a cable line across a major road which snaps of a couple of transmission poles.  Ice storms that have power out for days.  We see these about once a year to eighteen months. 

 

I have everything on my network setup to shutdown after thirty seconds on battery.  This takes care of the short stuff without a problem.  The longer events would require a motor-generator power setup in conjunction with a UPS.  Might as well shut everything down and save the wear-and-tear on the UPS battery.  (Those deep discharge cycles seem quite hard on these UPS type batteries.)  What I want from the UPS is to cleanly shutdown my servers.  I really don't need to keep them running when the lights are out...