[tech] [committee] Auction TOMORROW for UPS

[Matt]

Sorry for the double reply, got distracted by a fresher!

You can't spend more than $400 - please keep that in mind as you bid.

-Matt [MRD]


On Thu, Mar 10, 2011 at 8:38 AM, Matt <mattman at gmail.com> wrote:
> As I said in #committee this morning, I've been a strong advocate of
> UCC getting a UPS for some time - some people have however, raised
> very valid concerns.
>
> While post sitting on this one would be nice, given I'm in two minds,
> I'm going to provide my approval for the purchase at this time on the
> proviso that the batteries aren't going to require immediate
> replacement (hopefully you can talk to someone at Ross' about that
> Bob).
>
> I'll speak to Henry today about the procedure for getting a more
> formal quote out of FM for a 15A socket.
>
> I'd like to thank those who have weighed in both here and on IRC - its
> good to see thorough discussion around the purchase :)
>
> [MRD]
>
> On Wed, Mar 9, 2011 at 11:53 PM, Duncan Sargeant <dunc+wheel at dunc.org> wrote:
>> 2011/3/9 Daniel Axtens <danielax at gmail.com>
>>>
>>> > For the UPS' sake, running only for 90 seconds doesn't take the battery
>>> > anywhere near to the UPS' "discharged battery" threshold which, for
>>> > these
>>> > small SLA batteries, kills them without too many cycles to flat. I
>>> > suspect the
>>> > UPS manufactures underrate the battery and are relying on the idea that
>>> > most
>>> > power losses are short.
>>>
>>> This is one of the best thought-out responses I've received to anything
>>> this year. Thanks Harry.
>>>
>>> I've also been told on IRC that we do have machines dying due to power
>>> issues, and that, to [BOB] at least, not having to rebuild his screen
>>> session is worth $1000.
>>
>> What are you guys trying to achieve?  Power conditioning, 2 min uptime, 30
>> min uptime, or longer?
>> A well-maintained UPS can be expensive to run.  The equation is something
>> like: purchase cost + electrical install + 2-yearly battery replace/dispose
>> + service costs.
>> OK, so you can skimp on the last two, but - and I'm hazy on this - dying
>> lead acid batteries will just suck charge continually while not actually
>> charging.  But if it is a (more expensive) double conversion UPS (AC-DC-AC),
>> it will make a nice, but warm, power conditioner.
>> I'd get a quote for the extra circuit, because it may not be trivial if they
>> don't have capacity upstream.
>> My experience with UPSs is that sometimes it is better to have multiple
>> small ones than one big one.  They are more disposable, and operating on
>> common 10A circuits makes the electrics much cheaper (you can also get
>> yourself into trouble with overloading easier, I guess).  Liebert is a good
>> brand but even their service guys warned me that like everyone, they make
>> crappy consumer models too.  One thing I would stay away from are modular
>> UPSs.  APC and Liebert make them where you can hotswap PSUs in and out - the
>> general wisdom is that the hardwired ones are more reliable (hotswap
>> batteries are fine).
>> I just specced and installed them for a while, hopefully this post will
>> attract comments from others more clued into electricals :)
>> ,dunc
>