Is this good enough?

[wpeng]

I have a computer with a 250W PSU and the Dell 2005fpw rated at 75W. Will a UPS with 300W output be good enough to handle them?

I've seen reports on the internet saying they hook up two PCs and a CRT to one of these things, and the load is still 80%. I understand that the PSU is not running even close to 250W all the time, but what if I'm running a particular hefty game, running a taxing benchmark, or using some other resource hog?

 

[furballi]

Should work.

 

[jmagg]

That model should shut down your machine softly in the event of a blackout. The APC software will only shutdown the machine attached. The other will do a hard shutdown if the outage outlasts the battery.

but


That model does not have Automatic Voltage Regulation (AVR) technology, which keeps voltages constant during brownouts. In my area, short brownouts or line fluctuations caused reboots. AVR has taken care of that.

Just a heads up,

 

[wpeng]

Thanks!

Just a quick question though: how is it stable for a 300W output to support a 325W system?

 

[Navid]

Originally posted by: wpeng
Just a quick question though: how is it stable for a 300W output to support a 325W system?

It is not!
If you know that your PC will draw 250W when under load, it is not a good idea to use this UPS. Nothing may go wrong. But, it is not guaranteed. You will be using it in the safety margin. Like overclocking a chip!

You can find out exactly how much power an equipment takes using this.
http://www.p3international.com/products/special/P4400/P4400-CE.html

Don't worry about AVR. If there is a brown out, this unit will switch to battery and protect your system. It does not have AVR meaning that if the line voltage drops from 120V to 110V, it will not do anything and your PSU receives 110V instead of 120. But, if the voltage drops to 90V, it will definitely switch to battery.
If your PSU is so sensitive to line voltage that cannot handle 100V, you have a serious problem! Get a better PSU. Most PSUs can handle much lower voltages with no problem.

Another thing you need to consider is run time. That has to do with the battery capacity. When you get a UPS and load it close to max, your run time will be very short. That is not a problem at first. But, the batteries age. They die after 2 to 3 years. As they age, their run time decreases. So, if you are close to the max, you may need to replace the battery much sooner.

 

[jmagg]

Here is a example.

 

[Navid]

Originally posted by: jmagg
Here is a example.

That is interesting. I am not sure what is going on there!
If you look here (the datasheet for the UPS we are talking about) on the second page in the specifications, Brownout transfer is specified at 96Vrms. The transfer time is specified at 8ms maximum.

If the power supply is too sensitive, it cannot tolerate that transfer time (8ms). May be that is the problem. Obviously, AVR is good. But, it is not free. You have to pay for it. I just don't know if it is necessary. If the power supply is good enough, it should not have a problem with a 96V minimum line voltage. There are capacitors in the power supply that keep its output voltage constant even if the line voltage drops significantly for a shot period of time (8 milliseconds).

Edit:
I'm sorry! The problem is with the monitor. I don't know what is going on!