Page 1 of 2 12 LastLast
Results 1 to 10 of 12

Thread: Consumer grade power meters accuracy

  1. #1
    quest for silence's Avatar
    quest for silence is offline Silencer & heathen relic of a human (™ by OW)
    Join Date
    Sep 2013
    Location
    Italy
    Posts
    3,353
    Thanks Thanks Given 
    1,037
    Thanks Thanks Received 
    1
    Thanked in
    1 Post

    Default Consumer grade power meters accuracy

    Hi all.

    As far as you know, how much accurate consumer-grade power meters can be, I mean for for standby power measurements?

    I know (but I can't recall the source, atm) that very often the claimed precision (1%, 5%, etc.) is referred to a certain power range, while outside of that the mileage may vary, greatly, and that the minimum error can't ever be lower than the absolute value referred to that range.

    So, for instance, whether a power meter is "calibrated" (inaccurate terminology, sorry) to do measures for a 500W load within a 1% precision range, the minimum error can't be lower than 5W, whichever the device power draw will be.

    Given that, first of all is what I recall true? Whether it were true, what about home made standby power measurements on contemporary rigs? I mean those dual core Haswells which show an apparent idle power draw of about 10-15W at the wall (with 1 SSD, keyboard, mouse and network on, but no activity).
    Are those figures to be rejected as actually unreliable, or not?

    Thanks in advance for any insight.

  2. #2
    Join Date
    Jul 2011
    Location
    Germany, Berlin
    Posts
    1,616
    Thanks Thanks Given 
    969
    Thanks Thanks Received 
    30
    Thanked in
    24 Posts

    Default

    I really need to start publishing in English: https://www.computerbase.de/2014-05/...berblick-test/

    There are some decent cheap powermeters and some really crappy ones. The price doesn't exactly help.

  3. #3
    quest for silence's Avatar
    quest for silence is offline Silencer & heathen relic of a human (™ by OW)
    Join Date
    Sep 2013
    Location
    Italy
    Posts
    3,353
    Thanks Thanks Given 
    1,037
    Thanks Thanks Received 
    1
    Thanked in
    1 Post

    Default

    Quote Originally Posted by Philipus II View Post
    I really need to start publishing in English
    Is that sarcasm?


    Quote Originally Posted by Philipus II View Post
    There are some decent cheap powermeters and some really crappy ones. The price doesn't exactly help.
    Unfortunately Google Translator is really bad at german-to-english.

    So, summarizing, are all my expressed doubts groundless, and providing that a specific meter works correctly (something like the PM231E or the Volt Craft 4000), even just a single measure will be quite accurate (I mean a 13W reading can't be actually 8W as well as 18W), whichever the load figure is (I mean measuring 4W, 40W or 400W doesn't matter)?

  4. #4
    Join Date
    Oct 2006
    Location
    jonnyGURU forums, of course!
    Posts
    16,062
    Thanks Thanks Given 
    538
    Thanks Thanks Received 
    270
    Thanked in
    196 Posts

    Default

    Brand Electronics is the best for the money.

  5. #5
    Join Date
    Jul 2011
    Location
    Germany, Berlin
    Posts
    1,616
    Thanks Thanks Given 
    969
    Thanks Thanks Received 
    30
    Thanked in
    24 Posts

    Default

    Quote Originally Posted by quest for silence View Post
    Is that sarcasm?
    No, actually I'd like to do that. We'll see.

  6. #6
    Join Date
    Jul 2013
    Location
    Chino Hills, CA
    Posts
    282
    Thanks Thanks Given 
    16
    Thanks Thanks Received 
    1
    Thanked in
    1 Post

    Default

    Brand is good, but keep in mind it's only really accurate when measuring values of the same order of magnitude as the point it was calibrated at.

    So Brand usually calibrates them (using a big electric heater) at I think 800-1300W, you have a bit of choice in the matter. However if you calibrate it at that point and you try to measure something at 50W you're going to get results off by several percent. Without knowing this, I calibrated ours to an 81W load and I get excellent accuracy between 25W and 250W. But above 250W results diverge more and more from the Extech and Yokogawa meters, as well as from expected.

    I spoke to Brand's owner/engineer, and he says that he built a semi-custom improved version with multi-point calibration and refined circuitry that gets much better accuracy. I think he offered it for around $400. If you're interested in that you should call in person, he doesn't list it on the site.

  7. #7
    quest for silence's Avatar
    quest for silence is offline Silencer & heathen relic of a human (™ by OW)
    Join Date
    Sep 2013
    Location
    Italy
    Posts
    3,353
    Thanks Thanks Given 
    1,037
    Thanks Thanks Received 
    1
    Thanked in
    1 Post

    Default

    Quote Originally Posted by CM Phaedrus View Post
    Brand is good, but keep in mind it's only really accurate when measuring values of the same order of magnitude as the point it was calibrated at.
    So how the tiny equipment tested by Philipus II can be really accurate at low load, given that he used a 500W load from a Chroma (if I'm not wrong)? Is the "calibration procedure" you're talking about anything different?

  8. #8
    Join Date
    Nov 2010
    Location
    Australia
    Posts
    702
    Thanks Thanks Given 
    15
    Thanks Thanks Received 
    0
    Thanked in
    0 Posts

    Default

    Quote Originally Posted by CM Phaedrus View Post
    I spoke to Brand's owner/engineer, and he says that he built a semi-custom improved version with multi-point calibration and refined circuitry that gets much better accuracy. I think he offered it for around $400. If you're interested in that you should call in person, he doesn't list it on the site.
    $400? I think I'd sooner try this one - http://www.ebay.com.au/itm/RF9901-DI...item2a09d1238e

    The meter Wolf uses is only about $200pp from that seller. Not that it exactly offers $2000 Tektronics or Yokogawa type accuracy either, but it doesn't seem to have that issue with accuracy deteriorating outside certain load ranges.
    No wonder it doesn't work! You installed the coils backwards

    Main PC: Core i7 3770K 3.5GHz, Gigabyte GA-Z77M-D3H-MVP, 8GB Kingston HyperX DDR3 1600, 240GB Intel 335 Series SSD, 750GB WD HDD, Sony Optiarc DVD RW, Palit nVidia GTX660 Ti, CoolerMaster N200 Case, Delta DPS-600MB 600W PSU, Hauppauge TV Tuner, Windows 7 Home Premium.

  9. #9
    Join Date
    Oct 2006
    Location
    Moderator
    Posts
    6,504
    Thanks Thanks Given 
    149
    Thanks Thanks Received 
    3
    Thanked in
    2 Posts

    Default

    Quote Originally Posted by c_hegge View Post
    it doesn't seem to have that issue with accuracy deteriorating outside certain load ranges.
    I've just been impressed with how infrequently units are able to fool it. Only the Leadex platform has done it, and only at really low loads with the main power online.

    The Brand and KaW were constantly fooled.

    That's actually the seller I got mine from. Had to ask for the 120V version, and it was shipped direct from China.

  10. #10
    Join Date
    Nov 2010
    Location
    Australia
    Posts
    702
    Thanks Thanks Given 
    15
    Thanks Thanks Received 
    0
    Thanked in
    0 Posts

    Default

    My Cabac power meter gets fooled too sometimes. I opted not to publish a review on a low end FSP unit recently just because I didn't believe its readings. The power supply (an FSP350-60HCC) is not 80plus certified at all, but I was getting efficiency numbers of around 87% at 50% load - and that meter cost me about $150 (and is supposedly accurate to within 1%).

    I've been thinking about getting the Everfine 9901 (which I suspect is very similar to the Rek 9901, albeit without the universal power socket on it). The trouble is, though, that when I still have to purchase nearly every PSU I review and HWI still costs me money to run, I've usually got better things to spend another $150 on.
    No wonder it doesn't work! You installed the coils backwards

    Main PC: Core i7 3770K 3.5GHz, Gigabyte GA-Z77M-D3H-MVP, 8GB Kingston HyperX DDR3 1600, 240GB Intel 335 Series SSD, 750GB WD HDD, Sony Optiarc DVD RW, Palit nVidia GTX660 Ti, CoolerMaster N200 Case, Delta DPS-600MB 600W PSU, Hauppauge TV Tuner, Windows 7 Home Premium.

Similar Threads

  1. Should we use consumer grade PSUs for always on PCs?
    By Folktale in forum PC Power Supply Discussion
    Replies: 15
    Last Post: 08-30-2018, 09:46 AM
  2. At What Age do You Replace a Top Grade Power Supply?
    By Veloz in forum PC Power Supply Discussion
    Replies: 19
    Last Post: 11-06-2014, 01:43 PM
  3. Brand Power Meter Accuracy
    By CM Phaedrus in forum Testing Methodology Discussion
    Replies: 2
    Last Post: 03-25-2014, 07:35 PM
  4. LCR/ESR and capacitance meters
    By Siorus in forum Testing Methodology Discussion
    Replies: 2
    Last Post: 01-24-2013, 01:22 PM
  5. Power Meter with accuracy above 700W
    By SKYMTL in forum Electronic Component Discussion
    Replies: 30
    Last Post: 06-08-2008, 07:37 AM

Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •