Power supply issue

I have bought an Apple 20W USB-C power adapter to power the Kiwi SDR, as I read these are very good, but I have tried it and for some reason it doesn't seem to work. On connecting it the blue light flashes on for a second then goes off. Any ideas please.

Comments

  • What kind of cable are you using? Don't use the USB-C to DC barrel jack cables from AliExpress as mentioned here: https://forum.kiwisdr.com/index.php?p=/discussion/comment/17084/#Comment_17084

    Also, in general, if your cable is too long, or has too small a wire gauge, then you will get the "flashes for just a moment" problem. Because there is too much voltage drop on your cable: http://kiwisdr.com/info/#id-power

  • I bought a USB-C to 5.5mm 2.1 from Amazon (5 foot long) looks like that is the problem then.

  • Yes, 5 feet is much too long.

  • But also, a USB-C to DC barrel plug cable alone will not work as mentioned in the first post here: https://forum.kiwisdr.com/index.php?p=/discussion/3009/quiet-switch-mode-power-supply-smps-for-kiwisdr/p1

    You need a USB-A (note A) to DC barrel plug cable and then a USB-A to USB-C adapter that has the correct USB-C programming resistors so your USB-C power supply delivers the correct voltage & current.

  • Another question, is it a genuine Apple charger? ;-)

    • Here are the details of the cable I bought: Cable Length: 1.5m/5ft; DC Plug: 5.5mm x 2.1mm/0.22x0.08inch; Conductor: 24AWG; Cable Diameter: 4mm/0.16 inch; Maximum current support: 3A; Voltage:15V; Maximum Watt:65W


  • Yes, it is a genuine Apple charger, I read about not getting a clone.

  • Using an online voltage drop calculator you will find that a cable like that will drop a 1.5A load (possible Kiwi peak current at startup) to 4.6V. Below the startup voltage the Beagle will allow (roughly 4.8V).

    That assumes a copper conductor (not copper-coated aluminum), 5.0V at the supply, etc.

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