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Power Google Home Mini

Discussion in 'Audio' started by Rick Johnson, Jul 29, 2018.

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  1. Rick Johnson

    Rick Johnson

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    0
    May 11, 2016
    Im trying to power a Google Home Mini at the end of about 60 ft of wire (4 pr 18 gauge) double the pairs
    I have tried
    Using a 5v 2amp power supply (at the end the voltage drops below 5v google home will not boot
    Using a 5.8v 1.8 amp power supply with a diode or two to drop the voltage the google home will reboot after a few min
    Using a 12v power supply to power a USB car charger (5v 2amp output) Google home will reboot but run for at least 10 min
    Any suggestions
    I was thinking about using a LM7805 Voltage Regulator and power it with 12v. Not sure how much heat that would generate. It would be inside of a wall where I mount the google home
     
  2. Bluejets

    Bluejets

    3,794
    784
    Oct 5, 2014
    Sketch out a circuit of what you have and are trying to do.
    Your explanation is just confusing.
    Details of the load volatge and current requirenents also will assist.
    i.e. I for one have no inkling of what a google mini is or any parameters.
     
  3. Rick Johnson

    Rick Johnson

    22
    0
    May 11, 2016
    Thanks
    Google Home Mini is in Internet WiFi connected speaker Its power requirements are 5v 500ma
    All i'm trying to do is power the google home mini on the end of 60 feet of wire
     
  4. davenn

    davenn Moderator

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    Sep 5, 2009
    yeah you are suffering voltage drop

    do this variation But WITHOUT any diodes ... one diode will take you to 5V and you are back where you started
    2 diodes will take you well below 5V and you are worse off ....

    you will loose that 0.8V in the 60ft of cable and should hopefully still have 5V at the end of it. if you don't, then you could try a 6V supply


    Dave
     
    Last edited: Jul 30, 2018
  5. Audioguru

    Audioguru

    2,744
    621
    Sep 24, 2016
    If you have 12V at 500mA or more and use a 7805 with capacitors at the google home mini then the google home mini will get 5V and the 7805 will heat with (12V - 0.8V - 5V) x 500mA= 3.1W. The 7805 will need a heatsink that is not enclosed.
     
  6. Rick Johnson

    Rick Johnson

    22
    0
    May 11, 2016
    The 5.8v power supply dips below 5 volts when I apply the load If i use a 6v (6.2v) power supply the voltage at the load is 5.9 so google will not boot If i add a diode it drops below 5.
    When I use a 12 v power supply to power those USB chargers ( rated at 2 amp output) you get for your car and plug the google home into that the google home runs for a few min then reboots. Im not sure y thats happening.
     
  7. dave9

    dave9

    867
    213
    Mar 5, 2017
    Is it possible the USB car charger is poor quality and/or fraudulently rated for higher current than it is really capable of? I would measure its output voltage voltage under load, while the mini is doing something, say streaming music over wifi and playing it at high volume.

    Assuming it will always be powered on, I would definitely go with a switchinig USB power adapter of some sort instead of a lossy linear 7805, as having to buy one would still pay for itself in power savings and not have to deal with heatsinking and an enclosure.

    If you want to use a 7805 anyway for some odd reason, I would get a cast aluminum enclosure and just bolt it to that with grease. Some are even NEMA waterproof rated with a silicone gasket, but do mount the regulator to the bottom instead of the lid so it has the larger surface area to help.

    There are people who have used a USB power adapter and found that the USB cable they chose was low quality and that voltage drop caused it to reboot.
     
    Last edited: Jul 30, 2018
  8. davenn

    davenn Moderator

    13,502
    1,830
    Sep 5, 2009

    OK

    With the responses I read from them, I suspect Audioguru and dave9 were misunderstanding the problem .... and not understanding that it is a voltage drop problem over that 60 ft of cable

    For the 6V (6.2V) supply was that measuring the voltage at the other end of the cable ?

    1) You need to put the 6V supply on one end of the 60ft cable and measure the voltage at the other end WITH THE google unit attached <-- what then is the voltage ??

    2) You could go the 12V way ... put that into one end of the cable. and the 5V regulator at the far end of the cable ( where the google unit will be)
    dave9's suggesting to use a switching regulator rather than a 7805 is a good one
    they are dirt cheap a few bux off eBay eg
    https://www.ebay.com.au/itm/Waterpr...-Module/381462910417?var=&hash=item58d0f615d1

    find a supplier closer to you, select the 12V-5V version ... done


    you CANNOT put the 12V supply and the 5V reg at the same end of the cable ... it doesn't achieve anything


    Dave
     
    Last edited: Jul 30, 2018
  9. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

    25,309
    2,738
    Jan 21, 2010
    If you are using a 12V supply and a regulator of any type, the regulator should be on the end of the cable that is closest to the google home, AND you should have both input and output capacitors on the regulator. These capacitors are often (but not always) built in to the 12V car USB adapter and are external components other than the 7805 that you will require if you build it from scratch.

    It's also possible that the power supply on the google home is more than a power supply. The power supply for a google chrome, for example, also includes some of the networking hardware.
     
  10. kellys_eye

    kellys_eye

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    Jun 25, 2010
    Why not use a 5V power bank (rechargeable) at the local end?

    5V at 500mA is only 2.5W and a 5000mAhr battery bank would power it for 10 hours - probably longer if it is idling for any length of time.
     
  11. Rick Johnson

    Rick Johnson

    22
    0
    May 11, 2016
    OK dave9
    The USB car charger works good If I attach it directly to the power supply (1ft cable) Its when I move it to the end of the 60ft cable that I start to have problems

    Last night I took the power supply that Google provided and cut the cord to have a look there is one conductor (+) and its wrapped with a shielded ground. Would that mean that trying to power the google with 5 or 6v the cable is picking up noise and doing something with the Google mini

    davenn
    yes I measured the end of the cable with load on 6.2 at supply and 5.9 at load when I add the diode it drops below 5v. Yes the 12v and the usb adapter are at opposite ends

    kelly_eye
    The battey bank isnt a go I want to install around 8 of these throughout the house. I cant go around and recharge all of them every 9 hours. But I was thinking if the cable is picking up noise y could I not feed power bank with 5v and at the same time run the Google Home off the power bank. I think I have seen them with a power in and a power out. But again the size is a problem

    When I'm using the 12v feeding the USB adapter at the other end I monitor the voltage with the load attached and the voltage never drops below 12v but for some reason the Google Home Mini reboots after a few minutes.
    Im going to try Cat 6 wire first with the capacitors like steve suggested and then if that does not work look at the switching regulator only thing with that is the size I would not be able to get that inside the wall without a huge hole.
    Thanks Guys for your support
     
  12. dave9

    dave9

    867
    213
    Mar 5, 2017
    On the home mini it is just a power supply. Yes I was intending that the car USB adapter be on the end that the mini was on, with the assumption that hopefully it would have enough margin to regulate 5V after the 12V had dropped over the 60ft run.

    Wait, "inside the wall"? I would just string mains AC to an outlet, and plug the mini's power supply into it. It seems useful to have mains AC there if there are people there to use a mini, no?
     
  13. Rick Johnson

    Rick Johnson

    22
    0
    May 11, 2016
    I purchased a usb car adapter at walmart its supposed to put out 3amp Instead of those dollar store ones I was using. Yup that is doable putting in an AC outlet. I put the mini up on the wall 1 foot from ceiling and the intent for other locations was to put it on the ceiling so those locations I could use a switching regulator in the attic just above the Google Home.
     
  14. Rick Johnson

    Rick Johnson

    22
    0
    May 11, 2016
    It seems there is a difference (dont know what) in the dollar store version and a brand name USB car charger. I have had it running on the brand name charger for about 20 min now and working ok.¸
    So thank you for all your suggestions its nice to have input when things aren't working right.. If anyone wants to chime in on the difference between the cheepie and the expensive one Id be interested
    Have a good day
     
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