Any way to work out how long a UPS will last?

martz · Rated R Joined: 31 Jul 2006 Posts: 54

If i have a UPS of a certain size, with a certain load placed upon it, is there any way to work out (roughly) how long i can expect that UPS to perform for before the battery depletes ?

Manufacturers give values, but like fuel economy, those figures are open to wild interpretation imo.

Any ideas ?

Edit: Here's what i'm looking at to provide backup power to a hybrid pstn/voip phone system (draw load as yet unknown) :

http://www.apcc.com/resource/include/techspec_index.cfm?base_sku=SURT3000RMXLI

knight0334 · Posted: Tue, 01 Aug 2006 07:24:44 Post Subject:

Its elementary dear WATTson.

As soon as you know how many watts your system is using, and the volt-amp(watts = volt x amp) capacity of the UPS - you can figure out the life.

By law the manufacturer has to put a power usage label, engraving, or stamp somewhere on the device. It will have how many watts it uses.

martz · Rated R Joined: 31 Jul 2006 Posts: 54

eh-oop knight0334 ... long time no see pal Smile

i was having a blonde moment ... thanks for slapping me upside the head ....... mentally speaking Rolling Eyes

i didn't think it was just quite as simple as that .......

BeerCheeze · Posted: Tue, 01 Aug 2006 11:02:35 Post Subject:

Well..... it's not really. The problem is the batteries. Based on load every battery has a different drain level, so you would need to be able to get the stats for the battery and then figure out the load, and then the time to drain based on that load.

For example a battery may drain to 10% capacity on 10% load at 5% per minute. However when you put it under 50% load, it might drain at 20% per minute.

The better the UPS (i.e. more expensive) the better the battery, the longer the drain life.

T-shirt · Posted: Tue, 01 Aug 2006 18:56:07 Post Subject:

the APC runtime charts are fairly accurate for new fairly fresh, full charged batteries (batteries do age and lose capacity overtime and depending on the number of extended discharges), for something a vital as phone serivce/VoIP (you're not just looking to shutdown gracefully, but maintain service for an extended time/as long as power is out) you may need hours or days of capacity , beyond a few hours automatic generator and load transfer switches are more practical/affordable then massive battery banks
remember to add the modem/ routers and phones to the protected load side and calculate your needs accordingly.
How large a system do you plan to run?

martz · Rated R Joined: 31 Jul 2006 Posts: 54

the site has about 110 staff in one building with maybe another 30 or so branch offices situated around the country ....

T-shirt · Posted: Wed, 02 Aug 2006 18:13:10 Post Subject:

You are definatly looking at generators>transfer switch> phone system dedicated UPS circuits.
Spec your phone system first then let APC/others spec an adequite sized backup system to match.
Oh you better have a big budget this won't be off the shelf plug and play

DragonMaster · Rated NC-17 Joined: 31 May 2006 Posts: 134

goales · Rated PG Joined: 26 Aug 2006 Posts: 4 Location: CA, USA

According to your budget, you should start having UPS protection for vital servers, then secondary servers, then less common use servers, maybe the monitor (make it LCD) to control these servers in case you need to shut down.

After all these are protected, you can consider your bosses' PC, yours perhaps, then important people, then the rest Grin

bruceleeon · Rated R Joined: 15 Jun 2003 Posts: 59

you had me at "hello"