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Thumannator · Nov 15, 2007, 07:15 AM

I'd like to get a UPS (battery back-up) for my 24" 2.8 GHz Alu iMac. Having never purchased one before, I don't know what size (in terms of volt-amps) to get. I only need it to run long enough so that open apps can save and then the computer can be shut down. I believe APC's have software that does this? Their "help me size a UPS" doesn't strike me as being so helpful as it instantly comes back saying I should get the large and expensive 750 VA UPS, but that it estimates it will use 50% capacity.

So, two questions: what size should I get? and is APC's auto-shutdown software any good?

Thanks.

dowNNshift · Nov 15, 2007, 09:09 AM

I've used APC UPS's for years -- high quality, no maintenance, do their job well.

If you're only running an iMac on the protected side, I wouldn't go overkill -- a 350VA model will do just fine. Those sell in most retail stores for $39 to 45 dollars. Anything more than $50 you're wasting money. The bigger amperage models are for keeping servers on for 30 or 45 min until a generator can kick on -- or to keep a closet of telco equipment on during an extended outage.

The main benefit of using a UPS is that it trims and boosts power. Meaning that if your power company briefly supplied less than 120V AC, the battery backup would boost it. The opposite is true too... over-voltage and it trims to 120V AC 60Hz. This saves wear and tear on your computer (or other high end electronics) power supplies.

The only no-no with battery backups is to NEVER EVER connect a printer into the battery backup side. Reason being is that when a laser printer is idle it uses maybe 1 to 4 Watts.... but when you make it print it'll spike upto 600W instantly. This is bad news for the internal gel-cell battery. So, rule of thumb computers and other high-end constant power devices on battery protected side, printers and other on the surge protect only side.

mduell · Nov 15, 2007, 06:18 PM

Yes, APC is a great brand of UPS. My 1400VA APC SmartUPS has served me well for years (although it needs a new battery soon).

From the iMac specs: Maximum continuous power: 200W (20-inch models); 280W (24-inch model)

280W is about 475VA (worst case), so I'd go with the $63 550VA APC. Put only your iMac and external hard drive (if any) on the battery side; should give you about 15 minutes of battery life at typical load.

Originally Posted by dowNNshift

The bigger amperage models are for keeping servers on for 30 or 45 min until a generator can kick on -- or to keep a closet of telco equipment on during an extended outage.

VA capacity is unrelated to run time; run time depends on how big your batteries are. Bigger (higher VA) UPSs usually have bigger batteries, but not always.

Good advice on the laser printers; they kill UPSs.

Thumannator · Nov 15, 2007, 10:15 PM

I've wanted to get a 350 VA just to save some money, but I've considered that it may be necessary to go for a 550 VA. Either way, sounds like APC will interact with my iMac just fine. Thanks for the advice.

Thumannator · Nov 24, 2007, 08:29 AM

For the record, a 350 VA won't keep a 24" iMac powered long enough to do a clean shutdown. Back to the store...

Raman · Nov 24, 2007, 09:56 AM

Do you really need to do a shutdown or would putting it to sleep do the trick?

I my Windoze boxes I can use the Hibernate feature which basically writes the contents of RAM to the hard drive and then powers 100% off. You could literally take out the batteries and/or restart the computer weeks later.

Or there is a standby feature which turns off most things on the computer but keeps power going to the RAM. Pull out the battery or unplug it and you lose your work.

mduell · Nov 24, 2007, 09:27 PM

Originally Posted by Thumannator

For the record, a 350 VA won't keep a 24" iMac powered long enough to do a clean shutdown. Back to the store...

I won't say I told you so, but I, uh, did.

msackett · Dec 13, 2007, 02:01 AM

The only no-no with battery backups is to NEVER EVER connect a printer into the battery backup side. Reason being is that when a laser printer is idle it uses maybe 1 to 4 Watts.... but when you make it print it'll spike upto 600W instantly. This is bad news for the internal gel-cell battery. So, rule of thumb computers and other high-end constant power devices on battery protected side, printers and other on the surge protect only side.[/QUOTE]

My still fully functional, 6 year old UPS 400 (two outlets) has always had the HP LaserJet printer connected.

Seaking · Dec 13, 2007, 10:57 AM

Originally Posted by msackett

My still fully functional, 6 year old UPS 400 (two outlets) has always had the HP LaserJet printer connected.

And was this the HP 1200? I had that one on the UPS for a while and no worries. However today, only the boxes and their monitors go on the backup outlets. I can recall the model number of this UPS but with one PC and monitor running, I have 18 mins to shut it down. If NOTHING else, these are decent line conditioning devices as others have explained. (high lows)

mduell · Dec 13, 2007, 05:52 PM

Originally Posted by msackett

My still fully functional, 6 year old UPS 400 (two outlets) has always had the HP LaserJet printer connected.

Have you ever printed while on battery power?
Is your UPS standby or line-interactive?

hyteckit · Dec 13, 2007, 07:58 PM

Yeah, I wouldn't connect a Laser printer onto the UPS or a microwave.