[Nut-upsuser] MGE Evolution and programmable outlets configuration

Marco Chiappero marco at absence.it
Wed Dec 10 20:52:58 UTC 2008

Arnaud Quette ha scritto:
> [a quick walk through the ml, still from the UDS/Googleplex...]
> Hi Marco,

Hi Arnaud, good to read you!

>> A digression about the fan: it's really annoying not just because it's
>> louder than my 100W computer with 4 fans running (yes, it is), but also
>> because there's no need to keep it spinning all the time in a *small*,
>> *650* UPS generating just a *few* watts during normal use (measured with
>> a watt-meter and both the metal cage and the exhaust air are indeed
>> cold). Replacing it with a quieter fan, although fine for the UPS, means
>> void warranty. I'd like to have a little more attention on this aspect,
>> maybe using a thermoregulated fan, when paying 300 euro.
>> But I should address these critics to MGE rather than the NUT mailing
>> list, I know. However, beyond this issues, the UPS has proven to be a
>> good product, good-looking too :)
> you've been heard ;-)
> the point you might be missing is that the evolution range is a line
> interactive one, but more for small servers.
> and these are generally in some server rooms.
> for something more SOHO focused (and so less noisy), you should have
> opted out for Ellipse MAX (still line interactive, with 2 outlets
> groups too)

Well, I knew about the Ellipse MAX but I preferred the Evolution, which
is pure sine wave. Beyond this you are right, but the basic idea is not
to cool something that don't need to be cooled. For example the APC
Smart-UPSs (really similar to the Evolution line, line-interactive, sine
wave) 750VA and 1000VA are totally fanless. I'm sure that the Evolution
850 and 650 models can run fanless too, at least during normal use
(9-12W don't require an always spinning fan or a fan at all). Moreover I
suppose that nowadays low power UPSs are widespread in offices as much
as in server rooms, expecially the tower versions.
I can now ask you why the Evolution is using two different fan speed if
it supposed to stay in a server room? And, about the heat, where is the
difference, when not running on batteries, beetwen the Ellipse MAX and
the Evolution, fan excluded? Why is the first one fanless while doing
the same thing, with the same tecnology? ;)
Now, let's stop thinking of the fan, I love my Evolution and I like your
presence here. One more reason to prefer MGE. :)

> can I possibly contact you next week, when I'm back to MGE, to get
> some more feedback?


> now about the Powershare, these are things that I should have done for years...
> but since I've taken over the project leadership, there are far too
> many things I've not been able to give time to.
> now, the situation has evolved since my Eaton'isation. I'll have more
> and more time, and possibly somebody to work with me (but the crisis
> might void this point in the short run though).

(I know, in these weeks many projects are being delayed or stopped)
I have a couple of questions for you.
1) It's not clear to me whether the UPS is going to reboot or not when
mains is back again, if it has not been shutted down. Let's consider the
VoIP phone example, if I drain as much as I can my batteries (with the
deep discharge protection on) and the UPS is not shutted down by any
computer before it stops, is it going to reboot when power is restored?
I suppose it's not going to reboot in case the power is restored before
the UPS is dead, right?
2) The NUT documentation states that, usually, the event triggering the
computer(s) shutdown is the "low battery" state (or a timer when using
upssched). Now I see in psp (for windows, since there is no psp amd64
for linux :P) that it is possible to call the system shutdown on the
basis of (3) differen criteria. Moreover the "battery charge" criteria
seems not to be related with the low battery precentage (the one
activating the low battery alarm). Is this right? If so, why under NUT
is the "low battery" state the only one setting/criteria triggering the
system shutdown? It would be comfortable to start the power down
procedure when a certain battery charge is reached (not necessarily the
low battery percentage) or when there are still X seconds of runtime
available. The good thing is that the same method can be applied to the
switchable outles. For example I can set the UPS to cut the power on the
outlet.1 when the batteries are at 55% and have NUT starting the
shutdown procedure when the charge is lower than 70%. Or I can start the
system shutdown at 70% and before halting set outlet.1.delay.shutdown.
Unfortunately this require the system(s) to be aware of the outlet 
it(they) are using, and is going to complicate the NUT architecture, but 
such behaviour would make it *really* powerful! The "low battery" state 
can be still useful, to make systems shutdown as fast as they can,
eventually calling the UPS shutdown too. Maybe it can be used as event
for the last computer running, the one controlling the UPS, for example.
However I don't know if this can be achived easly, but maybe it sound
interesting and something can be done... just let me know your opinion!
Many thanks for your attention and thanks for this chat.


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