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Ammeter?

Discussion in 'Power Supplies' started by ShimmerNZ, Mar 9, 2016.

  1. ShimmerNZ

    ShimmerNZ New Elf

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    Is anyone measuring their power supply consumption on a permanent basis?

    I've been using a "Watts up" which I've had from my rc model days for measuring current draw while I've been setting up but was thinking about wiring something in permanently. Is anyone doing anything like that? If so what are you using?
     
  2. bpj1980

    bpj1980 Full Time Elf

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    Hey Shimmer, I am setting up a Voltmeter/Ammeter for each of my PSU's, I got one the other day, just a cheapie, I am yet to install it & set it up but once I have I will post a pic and some thoughts,
    I like the idea of seeing how it is all running so I know if any of my PSU's are reaching 65-70% load, then I need to get an additional PSU, well just my thoughts...
    I say do it... lol
     
  3. scamper

    scamper Senior Elf

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    I like the idea, But I wonder if one could set up a digital style that you could record a graph on a computer so you can see the average and peak draw and voltage drop etc.
    I think maybe because I am too lazy to sit and watch it throughout the show, but also to see when you may be drawing too much and change the sequence to suit.
    Sorry, got carried away, I was typing while thinking :)
     
  4. smartalec

    smartalec Im a SmartAlec what can i say! Community Project Designer

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  5. fasteddy

    fasteddy I have C.L.A.P Global Moderator Generous Elf

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    I have always designed a system with the theoretical maximum and then gone to 85% of that, that way you should always ensure you don't need a meter, Its never a good thing to run equipment too close to its maximum and if your peaks were too high then you would expect the power supply to shut down on overload, a decent power supply is designed to take 105 - 135% peak loads for short periods and the cabling will not get damaged with short peaks either, but its not good practice to design anything this way.

    But it would be a nice feature to just take a look at what the current is without having to work out any theoretical limits. The advantage to this would be that you could detect if you had water somewhere as you should see the current increase.
     
  6. Bill Ellick

    Bill Ellick Full Time Elf

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    I have used things like these on some boxes I built:


    http://www.ebay.com/itm/DC-100V-10A-Voltmeter-Ammeter-Blue-Red-LED-Dual-Digital-Volt-Amp-Meter-Gauge-/131577787046?hash=item1ea2a5b2a6:g:lFcAAOSwMmBVzF8~


    I had the boxes mounted on posts under my deck and with these facing the house away from the traffic, they made it handy to walk through and see what was going on quickly.
    I installed them with a plexiglass face over the display to waterproof them and so far they have lasted for 6 years on the oldest one.


    Just FYI, this is for a generic meter that I just looked up on eBay. I use similar ones but with shunts for some and different meters for others.
    Pretty much need to design the right ones for what you want to monitor. I know you can buy remote shunts and devices to monitor voltage and/or amperage but that can get costly quickly.


    Would be kind of fun to be able to sit in the office and see what each "box" was drawing out there in the display though!
     
  7. i13

    i13 Senior Elf

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    On the topic of current draw, it is not good practice to believe the current draw specifications for lights that you buy from AliExpress sellers. It is best to measure it for yourself.
     
  8. scamper

    scamper Senior Elf

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    That, along with voltage drops on cables and plugs and possibility of faults etc are why I think it would be good to look at current draw on each output. You can calculate all you want, but real life is almost always different.
     
  9. fasteddy

    fasteddy I have C.L.A.P Global Moderator Generous Elf

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    I agree that you should not believe the current draw specified by aliexpress vendors, but a 5050 LED will draw 20mA max per colour and a 2812B chip will output a max of 18.5mA, the 2801 will do 20mA per colour, its when you go to 12vdc and they specify that its 10mA when in fact it may be 20Ma( we have seen this with Ray Wu) is where the issues can come from. So based on the specifications of both the chip and the LED then you can make a good calculation on the current draw and in nearly all cases it will be actually lower then these specifications.
    I'm not arguing against using or having a current meter, just explaining that there is a way where you don't need to use one.
     
  10. bpj1980

    bpj1980 Full Time Elf

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    Hey Shimmer, so I finally got into gear and put mine on my box (still 2 or 3 to go) not much draw but it was only supplying power to a Switch, I am happy with it and cant wait to see it with more,
    I would show the cabling but its still not tidy to my standards ;) just slapping it all together to test for the moment.
    [​IMG]
    [​IMG]
     
  11. OP
    OP
    ShimmerNZ

    ShimmerNZ New Elf

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  12. bpj1980

    bpj1980 Full Time Elf

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    Hey Shimmer, i got the 50A one, it also came with a shunt for over 10A use, still need to load the PSU's up so i can see it running a little higher ;) , i will then test with my multi meter to see how close it is.
     
  13. OP
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    ShimmerNZ

    ShimmerNZ New Elf

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    thanks just found the 50a one with shunt....perfect.
     
  14. smartalec

    smartalec Im a SmartAlec what can i say! Community Project Designer

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    How fast do these meters react?
    as i have pure white for like 1sec max..
    is there any out there that will show the peak amps an keep in on the display for 5seconds?
     
  15. Odd_Socks

    Odd_Socks New Elf

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    Hi,

    I've got some ACS712 chips that I am hoping to connect to my PI, so that I can monitor and log the current over the network during the show.
     

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