Seasonic Power Angel Power Monitor

**Doctor Feelgood**

The Seasonic Power Angel strikes me as an item I am going to be glad I have for years to come. It can be an invaluable tool for anyone interested in determining operating costs, as it takes all of the guess work out. It has already proved quite informative in analyzing my computer and home appliance energy consumption, and I foresee continued use along these lines. - The Review

zepper · Posted: Wed, 01 Sep 2004 20:27:11 Post Subject: re. Power Angel review...

I thought you might want to know that there is another device out there very similar to the Power Angel (probably built on the same PCBs). It is the P3 Kill A Watt meter. It is nearly identical but I have been able to find it for a bit less $$$ than the PA (the best I've found for the PA is ~$35. +SHTx). The best price for the K-A-W (~$32. shipped) is from a guy in Hawaii via eBay.
. I have written a review of it on http://www.techimo.com/reviews/ .
. Now to your review. Your explanation of Power Factor wasn't very accurate. The number that expresses power factor is the Cosine of the phase shift angle between the current sine wave and the voltage sine wave. Since the Cosine of 0 deg. is 1, then that is the ideal and what is approached by PSUs that have active PFC (power factor compensation or correction). The description of 'Efficiency' is what you used to describe Power Factor. PF is a component of the efficiency number which is expressed in % (percent) (power out/power in x 100). IOW, the power factor of 1 is the PF of a resistor which is the most friendly load to put on the power grid. So perhaps if everyone had all their equipment PF corrected, the power company might not have to build more capacity quite as soon (that's why aPFC is required in Europe). And if you had several hundred PCs and switched all of them to PFC PSUs from non-PFC, you could save a couple bucks on your power bill.
. That brings me to the last paragraph of Page 2 where you were testing a small PSU with the Seasonic load (it would be nice if you would post a reseller link or two for that). The PSU is rated at 200W, and you were measuring about 200 Watts in from the wall. Assuming a typical switching PSU efficiency of 65% , then the PSU was actually outputting around 130 Watts into the load - nowhere near its rating... To get the exact output you would have to measure the output voltage and current on the rails that were actually being loaded with a DMM (Digital MultiMeter) and add them up. With that total, you could then calculate the actual efficiency of that PSU per the formula above. Perhaps that could be a useful addendum to any PSU review you may do here in the future - thanks to the Power Angel, of course... Wink

. I hope you find this enlightening.
.bh.

Wave

**Doctor Feelgood** · Posted: Wed, 01 Sep 2004 21:03:32 Post Subject:

Hi zepper... welcome. Your points are all well taken. The device from Seasonic, the "Loader" is not commercially available, but in a PDF they have published states that it can develop a max simulated system load of 146W. Indeed, the 200W measured by the Power Angel is from the wall, you are correct.

zepper · Posted: Thu, 02 Sep 2004 21:05:54 Post Subject:

Why isn't editing of our own posts allowed?

IAC, I meant to say in my paragraph on the testing of the small PSU:
To get the accurate total output of the PSU into the dummy load, you need to measure the Voltage and Current on each loaded rail, multiply them together (VoltsDC x AmpsDC=Watts) then total the power values from each rail.
.bh.

**Doctor Feelgood** · Posted: Thu, 02 Sep 2004 21:09:00 Post Subject:

Editing is allowed. Some people look for the edit button below the post (VB style), but it is above the post... upper right corner.