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No wattage info on PSU

By hitech0101 ยท 18 replies
May 24, 2011
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  1. I am using a circle cabinet + psu i checked on the sticker of psu there is no information about the wattage reading there are some other parameters given there like voltage & current but no mention of wattage the model no. is CPH 693 also the manufacturer doesn't have any website & i could find any thing about circle on the web.I have been using it for 2 years no complaints works fine but still curious about the wattage so is there any other way to find it out.
  2. Tedster

    Tedster Techspot old timer..... Posts: 6,000   +15

    use a multimeter. Volts x amps = watts
  3. hitech0101

    hitech0101 TS Guru Topic Starter Posts: 451   +32

    I have a multimeter can you please tell me how to measure where to connect the pins.
  4. captaincranky

    captaincranky TechSpot Addict Posts: 12,499   +2,294

    Double post, see below.
  5. captaincranky

    captaincranky TechSpot Addict Posts: 12,499   +2,294

    The rail amperage on the 12 Volt positive is the best indicator of a PSU's ability or capacity if you will. The 12 V rail amps, should be on the sticker.

    Using a multimeter is fairly pointless, as it will only tell you how much a PSU is delivering, and nothing about its max capability. Moving along, a multimeter won't tell you much of anything, as it can only take on measurement at a time, and there are more than 3 voltages that would need to be read simultaneously.

    The best approach to determine overall wattage is with a "Kill-a-Watt" meter: http://www.newegg.com/Product/Produ...5001&cm_re=Kill-a_Watt-_-82-715-001-_-Product, plugged in between the AC line socket and the computer. Here again, this meter will only tell you what the computer is drawing, but that gives you a general idea of how much wattage a prospective PSU should be.

    A US domestic Kill-a-Watt unit, (115 Volt 60 Hz), is about $20.00. I haven't the vaguest idea what they would be worth in your country.
  6. hitech0101

    hitech0101 TS Guru Topic Starter Posts: 451   +32

    Will look into it thanks for the help.
    One last thing i forgot to mention i haven't connected my monitor to psu i am running it independently how much load does it take off.
  7. captaincranky

    captaincranky TechSpot Addict Posts: 12,499   +2,294

    Neither does anyone else, so none. I have no idea what your AC line standards, but over here the monitors plug directly into the wall sockets. Why would you suppose that would have any effect on the computer PSU? Any wattage required by the video connection is very low, a couple of watts at most.
  8. jobeard

    jobeard TS Ambassador Posts: 10,432   +801

    the volts are easy to get; the amps are a problem.
    1. multiple rails at different voltages need to be measure and the added to get total amps.
    2. the MM needs to be in series with the load and the connectors don't make that too easy.
    3. and if you were working with a 500W PSU, you looking at somewhere between
      2.8a and 4.1a ; MMs don't handle hi current(aka amps) so make sure you don't exceed the rating of your meter.
    If you have the KVA rating of the PSU, then KVA x PowerFactor = Watts.
    PowerFactor is complicated to explain so I'll just state a common range
    0.9 >  PF > 0.6
    and if you took the lower number, then
    KVA x 0.6 would be the maximum power to be expected from the PSU
    (this would be a conservative rating).
  9. captaincranky

    captaincranky TechSpot Addict Posts: 12,499   +2,294

    Jobeard you can measure volts and amps to your hearts content, but that still won't yield the answer to the original question. Which was, "how many watts is the PSU"?

    All you will get totaling up the results from the multimeter readings is how much the computer is drawing from the PSU at that given time.

    If you're not gaming full on at the time, all you'll get is idle wattage draw at that.

    To measure the actual wattage delivery of a PSU a static load on the DC side must be employed. Then you can do the multiplication thing while you watch the temp readings go sky high and or the supply blow up in your face.

    AC wattage draw minus DC wattage delivered would give you the efficiency percentage.

    I believe the wattage reading you got just before the turd went up like a Claymore, would be the "maximum power" rating that many manufacturers would emblazon the sticker the case with.
  10. hitech0101

    hitech0101 TS Guru Topic Starter Posts: 451   +32

    We have 230V,50Hz but its around 240-250V at my home & many people here plug their monitors into the psu itself so it would have ups backup during power failure but i use it independently i thought it was deductible & take of some watts.

    I think its better to change the psu if i go for upgrades.

    Also tried for what joebeard said all i have on the sticker is 240V/63Hz/5A psu then a table with dc o/p:12v,5v,12v... then the connecters are mentioned atx,sata,....

    Thanks for helping guyz it helped a lot.
  11. jobeard

    jobeard TS Ambassador Posts: 10,432   +801

    If you read carefully, there were two kinds of comments
    1) that using the MM and attempting measure the amps is risking (and as you note, not sufficient)

    2) the KVA rating (if there is one) can be used to derive the capacity of the PSU
    which was the OPs request.

    Have a good day sir.
  12. captaincranky

    captaincranky TechSpot Addict Posts: 12,499   +2,294

    If both of you will take note, that even in well designed, honestly rated supplies, the wattage ratings derived from summing the total specified by the capacity of each rail, will most likely come to more wattage than the PSU is capable of delivering.

    In an Antec EA-380D the sum total wattage of the rails individual potential comes to about 550 watts. Yet it's only rated @ 380 watts continuous power.


    I think that most would agree that this PSU is of decent quality, and honestly rated.

    Point being, for one reason or another, it's pretty much a fool's errand to speculate about, or to reverse extrapolate, the actual wattage of a PSU not supplying that information.

    Specifications being the lies that they are intended to be, and PSU aging being what it is, the most prudent course of action is to replace the existing PSU at the time of any upgrade, and be done with it.
  13. hitech0101

    hitech0101 TS Guru Topic Starter Posts: 451   +32

    Is videocard the only thing that requires specific watt ratings or If i decide to add a HDD or optical drive then also i should be looking for the wattage?
  14. hellokitty[hk]

    hellokitty[hk] Hello, nice to meet you! Posts: 3,448   +145

    For the most part, you won't need to worry about a hdd or optical drive.

    Ideally, you'd hook it up to a known fixed load...and might consider using a clamp-meter for amps I think. But I'm no expert.
  15. captaincranky

    captaincranky TechSpot Addict Posts: 12,499   +2,294

    If we're talking about the same device you'd be measuring what's being drawn.

    Yes, a fixed or "static" load is required. But, even at that, the issue is a great deal more complicated than anybody has given credit for.

    You would need real time monitoring of all the voltages and amperage of all the rails, plus temperature monitoring. To complete the efficiency rating, the AC line side and the total DC draw must be measured simultaneously, and the differential noted.

    Oddly, if this PSU has no wattage rating posted, it seems like a cheapie anyway. Even the crapola PSUs take the time to post some BS story.

    With all of that said, doesn't this thing at least have a sticker that gives you the ampere rating of the 12 Volt + rails?
  16. hitech0101

    hitech0101 TS Guru Topic Starter Posts: 451   +32

    The +12V rail has a 14A & -12V has a 0.5A rating.
  17. hitech0101

    hitech0101 TS Guru Topic Starter Posts: 451   +32

    Also the psu doesn't have a 6pin PCI-e connector does this suggest it has a low wattage rating?
  18. captaincranky

    captaincranky TechSpot Addict Posts: 12,499   +2,294

    Any potent video card you buy will most likely need the PCI-E connector, so yeah, it's time for a new one.

    OK, if you'll follow this link provided by Leeky in reference to another thread, you should see the complexity and equipment necessary to determine the actual wattage and quality of a PSU, you should begin to see how disinterested I've become in this issue.

    You can't keep asking the same question worded differently, and expect different answers.

    If this were a decent supply in the first place it should have provided this information.

    I've asked you to provide the ampere ratings on the PSU sticker, these haven't been forthcoming. In an early post you suggested that these were present. These would be more apt to enable extrapolation of wattage, than some silly question of whether or not the unit has "X" connector.

    To wit; if it has say 20 amps on a single 12V rail, then it's probably around 300 watts. You could match these numbers up with different wattage units being sold, and figure generally what class the unit most resembles.

    But yes, the lack of a PCI-E connector does seem to imply that this unit is not for the enthusiast market. It's an OEM rebranded something or other.

    You can possibly find the manufacturer by Googling the UL listing number.

    If this is an older unit, it won't have the wattage it did when it was new anyway.
  19. hitech0101

    hitech0101 TS Guru Topic Starter Posts: 451   +32

    Thanks for bearing with me it helped a lot will take your advice & go for new psu for future upgrades. Thanks again !

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