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Hello spiceheads…i am in need of some assistance.

This question is going to come of very amateurish, because i know very little about power/electricity and the terms :slight_smile:

I will be going through all of my network closets and I would like to be purchasing 2 units per closet that will be powerful enough to keep my devices running for at least 5 seconds or more for generator to be able to kick in or even longer for those days where we get power flickers…

What do I need to look at on the switches/devices to add up to make sure i get the right size units? Looking at the APC website their units are sized based on VA’s, is this something on the back of all switches i can get and then just add up to know what I’ll need to run everything? Like if i have 3 switches that take 30 VA could i then get a 100 or more VA unit to be set? I’m just throwing out numbers here because i have no idea…I hope I’m getting accross what my actual question is :slight_smile:

@Eaton

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I’ll tag some of the UPS vendors for you so their green guys will see this thread, they’lll be able to give a better answer than I can

@Eaton

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Both Eaton and APC have selectors. Here is one from APC:

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Hey Justin,

Definitely a couple of things to consider here.

  1. the classic VA versus Watts discussion: I suggest you forget VA and look purely at watts. There are some technical situation where VA is relevant but it’s mostly used as marketing spin. All UPS specs will give you both a VA and a Watt number. You care much more about the watts supported and that will vary from UPS to UPS even if the VA is the same! IT equipment power supplies will be rated in watts so just make sure the total watts of the power supplies plugged into the UPS is less than the max watts of the unit (we suggest sizing at roughly 70% of the max watts to give a little overhead. So if looking at a 1000W UPS load it to roughly 700 watts)

  2. Run time: two things impact run time 1) the size of the UPS and 2) the load on the UPS. A UPS loaded at 70% will not run as long as the same UPS loaded at 40%. See the run time charts on UPS vendors’ product pages to figure out how long a UPS will keep a load up based on the watts loaded. Look at this one . You can get longer runtimes by either oversizing the UPS- ie buy a 3000VA unit to power 700 watts or you can purchase extra batteries that will connect to UPS to extend the run time without having to oversize the UPS.

  3. If you need compatibility with a gen set read this!!!

Another good resource is our UPS fundamental handbook (you will have to register to get it- so up to you!)

Hope this helps. Feel free to repost or PM me for more info.

Thanks, Mike

@Eaton

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Extremely helpful… so my last question is

What would be the difference between a 1000Watt/750 VA unit compared to say a 1000W/2200VA?

So say in 1 closet i need 700Watts, i know i need a 1000Watt unit, but is the VA just adding more run time?

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Nice write-up Mike. Another item is that I believe that Eaton UPSs can report in Spiceworks, right? There is a plug-in or something.

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Here’s my post linking to some of the available selectors

http://community.spiceworks.com/topic/297377-how-to-size-your-next-ups

Things to think about:

Get a unit with Network Management Card so you can monitor it (through Spiceworks!) or administer it remotely.

Do you need more than one unit for redundancy or for load? If for redundancy how will you handle devices with only one power cord?

Generators can take up to a minute to kick on. Most do it sooner but I know ours allows for up to a minute, larger ones may be longer before they are running and can handle the load.

Make it easy on yourself and try and standardise on one make/model, if you can. It’s ok to have a model for the server rack and another for desktops, but you could go nuts if you tried to get different units for each closet.

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You can have several UPS systems that are the same va capacity but have different wattage capacities due to power factor. So to agree with Mike J, measuring the watts of the equipment, and then checking the watts on the UPS system is always going to be preferred.

Also to reiterate, runtime is always going to be contingent on what you put on the UPS system. However if deciding on adding batteries to a UPS system vs. getting a larger unit for the same runtime, it’s going to be more efficient in the long run to add the batteries. If you put a smaller wattage on a larger unit it will have to work harder to compensate for the lesser power draw.

For generators I always suggest leading with an online UPS system. Generators tend to emit a dirtier power and with an online unit you’re going to get the cleanest power with a zero transfer time.

In order to size UPS systems the basic info I usually ask for is as follows:

  1. Makes and models or wattages of the equipment

  2. Runtime required in the event of a power outage

  3. If the UPS systems will need to support room for growth and if so, how much of a percentage.

  4. Electrical and outlets in the room to ensure what’s suggested will fit. Or if you look at UPS systems that require different electrical, can the electrical be changed.

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If you have a UPS with network card, or connected via USB to a PC or server that’s scanned by Spiceworks.

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1000 watts is 1000 watts. Kind of like a pound of lead and a pound of feathers weighing the same. You’d never really have a 2200 VA that’s 1000 watts though. (No one spins it quite that far!) Watts = liquid beer. VA = foam. Well, root beer in our Professor Wattson video on VA vs watts . One other item of note for network closets is that UPSs 1500 VA and below can be plugged in with a standard power plug. Go beyond that and you’ll likely need an electrician to wire the correct outlet for you. +1 on Limey’s suggestion for a network card.

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No. Just disregard the VA. In general the VA will always be higher than the watts. Best case, they will be the same (this is called unity).

So the difference between a 700 watt UPS and a 1000 watt UPS will be amount of power it can back up without overloading. If you load a 700W UPS with 800W it will alarm and not be able to support the load if it has to go to battery. If the overload is too much the UPS might even drop the load. But a 1000W rated UPS will handle 800W without a problem.

So if the IT in you closet totals 700 watts a 1000 watt ups will work great. Here’s an example. a 5P1000R is 1000VA and 770W this will support you load but will not leave you room for growth- if you need it. It will back up a 700 watt load for 6 minutes. Now if you used a 5P1500R (1440VA/1100W) you will get 10 minutes of backup time for the same 700 watts load.

make since?

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Right Limey, I guess I forgot to mention that little item. Thanks for the pickup.

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purchasing 2 units per closet that will be powerful enough to keep my devices running for at least 5 seconds or more for generator to be able to kick in or even longer for those days where we get power flickers…

Really surprised that nobody asked (even the UPS guys, tsk, tsk) if the power outlets were on the same phase of power.

To put all those units on the same phase of power will get very ugly for load balancing on the generator, and/or/ whole building UPS.

Check the generator for A/B, B/C, C/A phase loading. Get an electrician in to run different phases of AC to each of your closets, and plug one UPS into each phase.

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I skipped reading a bunch of the posts in terms of options if its for switches you need a sine wave power supply ups. Next on the list is a smart sinewave it boosts a sagging voltage and bucks a overvoltage and doesn’t turn to the battery to do the boost or switch to battery to lower the voltage.

Next is if you were going to power a computer that has a switching power supply… a standard ups won’t start under a heavy load so Cyberpower puts un the word ‘app’.

The next thing is VA and watts some units as you start running numbers are very inefficient… lots of VA in to get watts out.

In 2-3 years the batteries need replaced… lots of units lots of work…

IMO better to get a 5000 VA 4000 watt 5U rack unit with a choice of optional additional batteries… and run wiring… then only one component to monitor.

Best bang for the buck IMO is Cyberpower their thirsty to become a big player and so better on prices.

I would contact the reps at the various companies and do your research and make them give you multiple options not just a pat answer.

Best wishes.

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