5 Replies Latest reply on Jul 28, 2014 10:43 AM by kevincrouch4

# How long will they work at 230% load?

Hey guys. I'm the newest guy in our IT team so I'm not claiming to be very experienced in real experience. Heres the story. Friday night our real UPS system died on us. Needed new batteries (they hadnt let me set it up with a network connection or SNMP traps and monitoring or we would have known) so we replaced our one big UPS with MANY smaller UPSs. Tonight we had a small power outtage due to one of our smaller UPSs  going out on us. We shuffled some things to other UPSs and got everything back up and running, but with a VERY high load. According to the readout on the front of the UPS, 230% load.

My question is: how long will a UPS be able to function with 230% load running through it. I'm not asking how longs it's battery will last without mains power (the readout on the front was claiming eight minutes), but how long will the UPS be able to handle more load than it was designed for?

• ###### Re: How long will they work at 230% load?

NOTE: I am no expert when it comes to data center power issues. This is one of those times when a call to the vendor is worth more than the risk of upsell.

It's hard to tell from your post - are you running 230% of the rated load of the UPS? Meaning it's a 400VA UPS but you have it connected to a 1000 watt circuit and the servers connected are drawing 1000 watts? That sounds like a whole mess of problems waiting to happen because you are running way more juice through the UPS than it was designed to handle regardless of power outage or not.

Or is the panel telling you that it's 230% of the load it could provide for the rated UPS outage time? Meaning it's set up to provide 400VA for 20 minutes, but with your current load it could only last for under 10 minutes? That's less of a problem (until the power goes out).

• ###### Re: How long will they work at 230% load?

First, this is only meant to be a temporary solution - we have batteries for the real UPS on order and they will be in friday.

With these small computer grade UPSs The UPS says it has 230% of it's rated load plugged into it. Now, as near as I can tell, It is designed for 500 VA and, again according to he readouts on the front, it was pulling 1.2KW/hr of power or something like that. I dont think it had an actual VA display.

Either way, we both seem to agree they are WAY over burdening the UPSs and it's stupid., One has already failed and this one probably wont last long and will be worn out when it's done

• ###### Re: How long will they work at 230% load?

The Watts-to-VA ratio is W = VA x PF (power factor). Power Factor is the ratio of usable electricity versus the rated circuit amount. You can get THAT by entering the KW, amps (and volts and hertz if needed) on this web page: http://www.rapidtables.com/calc/electric/power-factor-calculator.htm

However, you are right - you're going to burn out that unit. The ONLY question is whether that will happen before or after the replacement batteries come in.

- Leon

• ###### Re: How long will they work at 230% load?

Exactly. The part that takes the cake is that my manager said "Oh it's just so they have time to shut down" but they are, in no way, monitoring or connected to the UPS with software. If the power goes out, the servers have no way of knowing it and will most certainly happily chug on until the UPS dies full blast unless someone from the 3rd shift production team (no third shift IT, too expensive) was to go and press the power button on each of the servers! and even then it's still not a proper shutdown!

New batteries came in Friday while I was out and were installed. Everything was switched back to normal high level UPS, but none of the UPSs that were used in the meantime will charge above 20%=they're shot. We wasted \$500 of equipment for no good reason.

No one ever listens to the new guy >.>

• ###### Re: How long will they work at 230% load?

You're risking an abrupt shutdown of the equipment. My opinion is that your risk is lower if you plug the equipment directly into commercial power than it is plugged into a UPS that is that grossly overloaded.