As some of you may or may not know, I do know my way around PSUs, and I've been wanting to get an UPS for sometime to protect my computer (only got a voltage regulator), the reason I haven't was money (or lack of it), but that's about to change on next payday. Even though I'm a newegg boy now, I won't be ordering this online simply because it weighs a crapload to ship it back to my country so I'm going to pick one up at a local store.
I had in my mind the APC BE550R (My store has it for $56), but I don't know how much juice it needs to have to run my computer flawlessly. I'm planning to hook up my 17" CRT Monitor, Logitech X-530 speakers, and my computer only.
I highly recommend this one because my friend uses it and the battery last about 20minutes on a fully loaded high end PC, which is enough time to save the data and shut down/hibernate. (8800GTX OCed, 3 HDDs, 1 DVD RW, 4 80mm fans, Q6600 @3.1Ghz).
A ups is a good idea, particularly if you are prone to sporatic interruptions. I have a APC XS 1500 with the optional battery pack, and it is overkill.
To size what you need, there are numbers that tell you how many watts the upc can handle and how many minutes the battery can sustain that load. The APC can use the "powerchute" monitoring program which I find handy. It gives you statistics on outages and durations, and can shut down the PC if the ups is on battery and it is getting too low. The upc has a built in voltage regulator, so your old one is probably not necessary.
If you just want to stay up for a few minutes to go through a momentary power surge, or have time to gracefully shut down, then the unit you referenced should be ok. If you want to do some useful work for an hour or two, then a unit with a much better battery will be needed. You probably want to also connect your modem. Perhaps not your speakers to save the battery.
APC measures it's UPS's in VA. This UPS cannot handle 550 W, but closer to 300-350 W. You should also be aware that a CRT will draw relatively much power. In general it's not worth protecting a CRT with an UPS.
If your PC has a 400 W PSU with an efficiency of 75% there's no need to buy a PSU rated higher than 600 W (around 800 VA) for the PC alone, this includes a 20% overhead. But if you plan on using the PSU for several years to come and perhaps another two PC's, I'd suggest the PSU geofelt uses (1500 VA).
Oh yeah I forgot... it's an Antec NeoHE 500 (Efficiency is over 80%, i believe around 82-84%), and I guess I could leave the speakers and screen out if I can at least protect my PC with that APC BE550R unit.
Power outages are not THAT frequent where I live, so I'd just like something to help protect my PC in case something were to happen. And there's also an APC BE600 (600VA/360W) for $95, I don't see it being that much more powerful over the BE550R so I didn't consider it, but I'd like an opinion of whether it's worth the extra $40 or not?
This may be a stupid question but I was wondering if there are any disadvantages to using an underpowered UPS (other than a very short runtime). I am using a 550 VA for my computer and a very old 350 for my LCD. I am able to get about 9 minutes of runtime which is plenty for me.
CRTs munch power as has been said. I wouldn't recommend putting a CRT on a UPS.
I have an 8800GTX SLI, Core 2 Extreme QX6800@ 3.73GHz, nForce 680i, 4*HDD, PhysX, Xfi card, 30" Dell 3007WFP-HC, and Creative Gigaworks S750 speakers all hooked into a 1500VA UPS.
Idle in Windows, the UPS draws 630 Watts from the wall, or 680VA. The PC itself has a 1kW PSU on, and at full load it lights all 5 "capacity" lights on the UPS. The UPS will have inbuilt power factor correction however, so it probably has more than 680VA being drawn from it.
With a 500W PSU in your system, the max draw will probably be in the region of 650VA. VA do not equal Watts, as you have to account for Reactive and Capacitive loads in an AC circuit, which may increase the apparent power (VA) over and above the true power (W). You are of course probably not using all the capacity of your PSU, but there is no point in having a UPS rated for, say, 80% of your PSU capacity.
There is no advantage to putting your Voltage Regulator before the UPS, the whole point of the UPS is its ability to trim incoming voltage over a certain range, or switch to battery in extreme high inputs, boost voltage or switch to battery in extreme low inputs - it performs the voltage regulation task already.
If you overload the UPS, you will either a) have a pathetically short runtime, possibly measured in seconds, or b) cause it to trip out and not switch to battery.