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UPS Capacity/Runtime

UPS Capacity/Runtime

UPS Capacity/Runtime

How do I really know what UPS to get for a server (or any computer for that matter)?
We have a Dell poweredge 2900 server (2008 build) and based on the specs it has a 930W power supply.
That presumably is how much the psu CAN deliver- it doesn't tell me what power is actually drawn from the AC supply.

I tried APC's handy selection calculator on their web site - entering 1000w for power and 15 minutes for runtime.
It points me to a smart ups 1500 RT at about $1,544 but the advert does not tell me the actual runtime- it says 'extended runtime model'.

Yet I see costco adverts for APC backups pro 1500 models at $200 and they seem to indicate you can expect only 3 to 4 minutes runtime!

So is the APC site's recommendation for my requested 15 minutes runtime flawed, or is there really a huge difference between the smartups 1500 and the 1500 pro runtime?

I don't know much about these except the person before me bought a Smart-Ups 1000 (the big heavy one)with the poweredge 2900 in 2008 and it has been not-good recently; despite replacing batteries a couple of years ago it recently died after only a few minutes when the power was out for a while.
Now the box stared beeping and the LEDs flashing so I assume it means the batteries are useless now.

I do have one of those lower cost APC Backups pro units ( a 1300 unit) on another computer and it did last longer than the big SmartUps 1000 although the load is likely lower than the Poweredge!!


RE: UPS Capacity/Runtime

With all my clients, I order refurbished UPS unit/batteries. Not only are they much cheaper but the batteries are fresh, unlike a few units I order new from big name warehouses, receiving units from them which sat on a shelf for over a year (batteries lasted a little over a year). On my raid equipped 2900s, monitor, tape drive, I used APC smart UPS 2200 towers (generally). It is foolish purchasing new units at high prices, have roughly 40 refurbished APC SmartUPS units installed at clients, they just do not die.
You want to purchase over sized units, so as batteries age, capacity going down, they still maintain the ability to keep the servers up. If you get a minimal unit which last 5 minutes now, in a couple years, that could be down to 1 minutes. Basically in ordering, the larger the actually weight, the longer the run-time, I always check the weight.
Purchasing UPS units\batteries from a major warehouse is a gamble, they purchase large quantities for discount pricing and you hope you get one which moves off the shelf fast. They also purchase old stock, at great prices, which has sat on someone else's shelf for a couple years.

I order from this company....

Battery life varies on any UPS units, primarily on how longer that sat in storage before you purchase them, the storage temp, and them ambient temp when in use. Just replaced the batteries on a 2200 tower unit the other day, the batteries only lasted 3.5 years ( which is pretty good) considering the room they are in is not air conditioned, warm all year, reaching >85 F most of the summer in NYC.

"That presumably is how much the psu CAN deliver- it doesn't tell me what power is actually drawn from the AC supply."
You need something like this, or a multimeter with an amp probe to figure true wattage....


Chernobyl disaster..a must see pictorial

"Computers in the future may weigh no more than 1.5 tons."
Popular Mechanics, 1949

RE: UPS Capacity/Runtime

Thanks Technome - that is very good advice about refurb units and the size.
I can see now that there is a real difference between models and going by the runtime/load curve on one of these 2200 boxes that is more like what we need; clearly the lower cost 1500 units I mentioned are not useful except for short power interruptions.
We are based outside a town and power outages, although not frequent, can be extended- certainly more than a few minutes.
I would prefer to give a server a few minutes time waiting for power to return then begin shutdown. I find the Poweredge 2900 takes qite a few minutes to shut down too.

Thanks again,

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