[SWLUG] Re: UPS etc

[Peter Joseph]

> For my use, I'll be running an LCD monitor (from its
> transformer), a dual-supply PC with 2 HDD, 3.5, LS120,
> DVD, CD, card reader, cordless mouse and external
> modem.

Wattages...wattages. Shall I assume two 300 watt power supplies? Just with
that alone your already looking at more than your entry level UPS.
http://www.apc.com/template/size/apc/index.cfm

That is APCS fab selector, it asks detailed info about what you want to run
and tells you how much runtime to expect with selected ups. If you dont want
to buy APC just use their power usage estimates to select another brand.

I would really recommend getting at least 30 mins runtime....you dont really
want to have to reboot for a 5min 5second powercut! (you may just have to
run down to the basement or something to reset a breaker) I think the
chances of the power coming back on within 30 mins are pretty good most of
the time :D
>
> I'd estimate that the battery should last the 5
> minutes needed to close everything and shut the system
> down. Really, what I get is occasional 1 second
> powercuts. That's enought to make XP throw a wobbly.

Please elaborate on 'wobbly'.... 1 second power dips are going to make
99.99% of machines reboot.

> At the moment, the plan is to protect the xp machine.
> If at a later stage, I need to protect the others too
> then I may have to think bigger.

How about this....Get an ups with enough capacity to power your server for
say 15mins - 30 mins, it needs to be able to communicate power status with
the server for this.
Then get a few cheaper smaller UPS for your other machines (no comm features
required for these).

You can then use the Linux UPS monitoring software as a server for which the
other machines on your LAN can communicate with regarding power status.
When the server detects (via its own ups) that power is down it informs the
'client' machines that the power is off and they begin their automated
shutdowns (after a period).

Basically it means you can get a really functional UPS setup with
autoshutdown on all machines for a fraction of the cost of either:-
1) buying 'normal' capacity ups with comm features (price: ££)
2) buying a 'huge' ups with comm features (price: £££££)

I toyed with the idea of setting this up myself, but its not happened yet!


>
> It would be interesting, since everything inside a PC
> runs at a low voltage, as do LCD monitors, to see an
> extra power input for low voltage supplies so that a
> UPS could be plugged directly in order to save the
> power loss from inverting the battery supply before
> reducing it through a transformer to get back to the
> same basic voltage again.
>

Not sure what your saying here, but dont forget the mains is AC and has to
be inverted anyway, so having a low voltage output on the UPS wouldnt really
save much.

>

Pete