[tech] [committee] Auction TOMORROW for UPS

[Matt]

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