240v IEC to USB Power adapters?

Discussion in 'Electronics & Electrics' started by Azrael, Feb 1, 2019.

  1. Azrael

    Azrael Member

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    Im on the search for a way to slim down some RPi stuff im doing, and was hoping to find some slimmer USB power adapters than the wall wart style.

    Was hoping to find something that takes an IEC C13 (kettle) or C7 (fig8) cable and a USB socket output.

    Sony included a C7 to USB brick with the RX100, but it was only a 1.5A charger, so doesnt provide enough power for the RPis.
    [​IMG]

    A long bunch of googling and the like has turned up nothing. So im turning to crowd sourcing. Anyone found something suitable for their projects?
     
    Last edited: Feb 1, 2019
  2. Hater

    Hater Member

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    I had one for a Linksys Router. 5V out, was 3A or so. Normal DC mate/female connector, I lopped that off and wired in a MicroUSB cable instead. Worked a treat.
     
  3. OP
    OP
    Azrael

    Azrael Member

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    Thats a good idea, except that it seems just as hard to find 5v 3a brick transformers.
     
  4. Hater

    Hater Member

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    yeah was pot luck that I found one in my draw of old crap :) it's 5 amp now I think of it...
     
  5. OP
    OP
    Azrael

    Azrael Member

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    So it seems that Sony are either particularly talented at specifying the amperage of their hardware, or the assembler over specced this one, but im drawing 2.6A off this 1.5A rated charger. No apparent heat issues, so ill run with that.

    Time to go find some more adapters.
     
  6. aXis

    aXis Member

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    Have a look at some of the USB charging stations at Bunnings. Some of them come with 4 ports / 4amps on a IEC lead.
     
  7. bcann

    bcann Member

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  8. Matthew kane

    Matthew kane Member

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    5v 3a+ rated DC adapters are easy to find on ebay. These usually power small poe switches or cisco routers.
     
  9. v81

    v81 Member

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    OP, how many PI's
    Running wired or wireless network?
    I have a Pi3 running on a PoE adapter from E-Bay, but having a HP PoE switch to begin with gave me a head start.

    There are plenty of power supplies with 5v out, but not necessarily in the form of a USB out.
    Meanwell make a few good value units, and E-Bay is also a good source.
    ADM Tech in VIC have this range..
    https://www.meanwell-power-supplies.com.au/power-adapter/desk-top?f[0]=field_output_voltage:5V
    If running multiple PI's from one unit allow a minimum of 1.5A per Pi if running Pi only, no accessories, else min 2A each.
    2.5A is a safe margin for a single pi, but when combining a few they rarely hit power peak simultaneously.

    This unit with the plug cut off and a micro USB plug put in it's place would do fine.

    Pi3's are ok running from a 2A PSU providing it's a legit 2A and there a few or no accessories plugged in.
    Having a short and/or heavy gauge power cables in the USB lead also makes a definite difference.

    Gotta run, will check back later
     
  10. Stooge007

    Stooge007 Member

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  11. dakiller

    dakiller (Oscillating & Impeding)

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    Do you need >2A to run your raspberry pi? Cause a top of the line 3B+ will idle at less than 500mA and you probably won't go over 700mA

    https://raspi.tv/2018/how-much-power-does-raspberry-pi-3b-use-power-measurements

    The things that pulls power is the USB devices you plug in after that.

    The Raspberry Pi people specifiy 2.5A as kind of the worst case limit, and just so they don't have to deal with thousands of kids going 'wah, my pi don't work, you suck' they put these specifications to cover any case and to rule out bad 5v adaptors.
     
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  12. v81

    v81 Member

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    As dakiller says above the average current draw isn't a lot.
    Not sure what instantaneous peak is, the article linked to admits that it is missing this data, but that said it still wouldn't be anything significant.
    Remembering an experience running a Pi3B+ a few months ago from a Xaiomi powerboard with 3 x USB power outs, Pi running OSMC.
    Was getting the lightning symbol on boot (power supply inadequate warning).
    After swapping to a shorter and more reputable USB cable the issue went away.
    I'd be thinking supply voltage of 5.1v to 5.2 v and a short USB cable with good conductors would solve the issues most people have with power supplies.
     
  13. treblid

    treblid Member

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  14. OP
    OP
    Azrael

    Azrael Member

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    To update, several single Pi's in different locations, so only need one USB output per IEC socket. They are all running screens though and at least one USB device, so the HDMI output and USB chipset chew some power.

    I found a source for good PSUs in an unlikely place: Apple 12w USB power adapters. You can pull the adapter off and put a C7 IEC cable into it which is then easily adapted to C14 IEC. Plus they are much easier to get OH&S certification for than something that is direct import from China.
     
  15. Hater

    Hater Member

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  16. fad

    fad Member

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