UPS recommendations

My experience with UPSses is that a UPS actually causes more power outages than it helps to prevent. A UPS needs maintenance and can break down. Its far from something you kick in the corner and live happily ever after. So if you really want to increase reliability you'll need a coputer with a dual power supply each powered from a different source.

A page that gives an idea where you're sending your money:

APC... Powerware... And a few others. Any unit rated for commercial or SOHO will probalby be OK if it is not a cheap Chinese import.

APC, we've been using a 1500 on the server for the last 5 years, no problems, 15 minute reserve. Battery replacement alert, web server in Powerchute to monitor the status.

figure 600 VA per system that you want to protect.

Cheers

Just another reason for a laptop computer.

for the same price you coulad have a faster desktop with a full keyboard, a larger screen and a UPS that'll run it for longer than the laptop battery.

That was our experience back when I worked for the RI Sec. State's office. We had invidual APC UPS's on servers but to be honest it became a maintenance nightmare.

When it came time to move the corporations and elections divisions I made the push that since those were our two biggest support units, I.T. should move with them.

Managed to use HAVA money to build out the datacenter. Replaced all those little APC's with one big one, a Symmetra ultimately designed for a minimum of 15 minutes backup power. We overbuilt, in the end we had 45 minutes.

Plus that Symmetra was backed up by a 125kW natural gas fired generator that kicked on within 10 seconds of power fail.

Nice solid power and the Symmetra would email both us and APC when a battery in the massive bank needed replacement. The next day the new battery would show up and it was easy to just snap it in.

We tried for maximum redundancy. But the fly in the ointment was DNS services. The state's DoIT (Dept. of I.T.) provided all DNS services for us and one time there was a massive power failure in the city.

All our stuff was up and running including phones (Yes, we put the pbx on the Symmetra too!) but without DNS we couldn't get out, and people trying to hit our sites couldn't get in.

Kind of made the point that DoIT had to have redundant power too.

And 2 UPSs. No amount of redundant PSUs will help if the mains fails.

FWIW, my experience has been somewhat better. I have a 500VA Liebert PSA, and the only problem so far was that it needed a new battery after 5 years of 24/7 use. When the battery died, the alarm sounded and the warning indicators lit, but it continued to run okay (presumably it wouldn't have worked in the event of a power failure).

In that time, it kept the computers (2 PCs) running through brief (< 1min) power failures which occur maybe 3-5 times a year, plus 3 longer failures where it allowed for a safe shutdown. It hasn't caused any outages, although I daresay it will cause one when it eventually dies.

Most UPS supplys charge an internalbatery when the line is good, and a relay drops out at power loss, switching the UPS online. Most are good for about 15 minutes, more than enough for a graceful shutdown. Just make sure the US is rated for at least the the same amount of max power the devices (computer,printer,modem, etc) draw.

Strange, about 10 years ago i got a USED UPS and it never gave me any problems, other than needing a new battery after 5 years of use.

On 03/01/2009 01:09 AM, Robert Baer sent:

That is the definition of an SPS. An SPS is a "poor man's UPS" and is not a very attractive solution for IT applications. The OP would probably want an "On-Line UPS" where *no break* output power is supplied to the load until the unit is turned off, or the batteries reach a pre-determined point where internal circuitry shuts the unit down when nearing battery exhaustion.

Pete

That is the UPS designed only for IT applications. For example, IT equipment is intentionally designed so that "break" output power causes no problems. Furthermore, IT equipment is designed so that 'dirty' power from a typical UPS (that can harm small electric motors) does not harm IT equipment.

Robert Baer accurately described a computer grade UPS. Typical PC user has a $100 UPS. "No break" outputs or to provide hours of power requires UPSes of $500 or more. IOW a UPS to do what any laptop does means more money - not less as another has claimed.

A typical computer grade UPS provides sufficient power to save data.

You are talking about one UPS. I'm talking about experience with a whole bunch of UPSs which are not located under my desk!

You don't want an on-line UPS for a simple reason: reliability. In an on-line UPS the electronics are always working which causes quicker deterioration. An on-line UPS is more complex so more things can break. And last but not least the electronics in an on-line UPS have to deal with the rush-in current from the load as well.

And there is no need for an on-line UPS. All switching power supplies are designed to allow a few missing mains cycles so having a relay that switches between the mains and the battery powered inverter is not a problem at all.

APC, American Power Conversion. I sold them for years

In other words you didn't do any decent preventative maintenance, yet expected everything to keep working. How hard is it to inventory them and set a battery replacement schedule? All of mine were still giving good service after five years, when it was time to replace the batteries.

When I can get a laptop with a 22 inch monitor, decent speakers, a laser printer and a flatbed scanner, I'll consider it. Until then I'll use a UPS with each desktop computer.

Yeah I had a 12 KW Liebert at work. I had to replace the batteries in it twice. 64 6v 9 ah batts. What a pain in the ass. But it did work ok. We ran separate ac feeds to all our computer stations. We also had stand by generator that picked up after 30 seconds or so. If it started. That was also a maintenance hog. Eric