UPS dying...

[Bob Jonkman]

On 12-09-11 10:03 AM, Mark Lane wrote:

> What you need to know is Peak wattage at startup and the Peak wattage
> under load.

The first time I specced out UPS requirements for a small server room I
calculated startup current draw by hand[*] for the servers, switches,
modems, &c., since I didn't want to overload the UPS coming up from a
blackout.  Turns out I over-specced the UPS by some 40%, since I was
later told by an APC rep that the rated power of a UPS allows for brief
overloads, precisely to account for startup loads.  Of course, it would
have been good to know this before buying the thing...

--Bob.

[*] Before the Internet was invented. Or at least, before the Internet
was commonly available, but definitely before online UPS calculators
were invented.


Bob Jonkman <bjonkman-w5ExpX8uLjYAvxtiuMwx3w at public.gmane.org>         http://sobac.com/sobac/
SOBAC Microcomputer Services              Phone: +1-519-669-0388
6 James Street, Elmira ON Canada  N3B 1L5  Cell: +1-519-635-9413
Software   ---   Office & Business Automation   ---   Consulting


On 12-09-11 10:03 AM, Mark Lane wrote:
> On Thu, Sep 6, 2012 at 9:34 PM, Digimer <lists-5ZoueyuiTZiw5LPnMra/2Q at public.gmane.org> wrote:
>> On 09/06/2012 09:03 PM, Peter King wrote:
>>>
>>> My UPS seems to be dying.
>>>
>>> It's an APC Back-UPS XS 1000, which I've had for several
>>> years. Recently it has begun to trip into "Overload" mode
>>> for no apparent reason (no particular load was being put
>>> on it), at random but ever-more-frequently occurring times.
>>>
>>> The battery is probably no longer holding its charge, and
>>> hence the "overload" it reports.
>>>
>>> So it's time to get a new UPS.
>>>
>>> I have a computer with a 650w power supply, a monitor, and
>>> a few miscellaneous devices to run. Only the computer and
>>> monitor need go through the UPS backup power, but it would
>>> be convenient to have surge protection for the other devices.
>>>
>>> I don't need much time on the battery; a few minutes should
>>> be enough for an automatic controlled Linux shutdown.
>>>
>>> How "much" is enough -- is 1000w fine, or go for 1500w for
>>> the extra margin? I don't have a clue about these things.
>>>
>>> Advice, suggestions, recommendations?
>>
>>
>> The rated wattage of your PSU is not an indication of the current draw.
>> Unless you have some serious hardware in your machine, you are likely
>> drawing less than 200w on average (at least that's the load I see in most
>> cases).
> 
> That would be under no load with only one monitor. (and Printer should
> not on the UPS). When buying a UPS average wattage is pretty well
> meaningless for anything more than determining runtime on battery.
> What you need to know is Peak wattage at startup and the Peak wattage
> under load. The easiest way is to use a UPS calculator which already
> has the wattage information for various components specifically
> Processors and Video Cards.
> 
> Here's Eaton's Calculator.
> 
> http://powerquality.eaton.com/UPS/selector/by_WorkStation.asp
> 
> I definitely would recommend Eaton (Powerware) UPSes but they are
> probably too expensive for most consumers (me included).
> 
> I can also speak to the CyberPower. I was a little iffy about buying
> it at first but the price was excellent. It's worked well since I got
> it save some issues with it's software. The 1500VA model is currently
> powering both my PC and my iMAC Pro without issue.  So it would be
> more than enough for your system Peter.
> 
> 
> Mark Lane <lmlane-Re5JQEeQqe8AvxtiuMwx3w at public.gmane.org>
> http://2100computerlane.net
> --
> The Toronto Linux Users Group.      Meetings: http://gtalug.org/
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