Google home mini hardwired

Thread Starter

trickyrick

Joined Sep 18, 2013
43
How do I do this
First I don't understand this
Google home will run off a usb port with max current at 500ma
Why is the power supply rated at 1.8 amps
Ok I have run 4 runs throughout my house using 2 pair 18 gauge phone wire I have doubled up on the pairs, runs are about 50 feet
I found a wall wart rated at 5v 2.5 amp so I spliced that to one end and when I tried the google home it would keep rebooting when I measured the voltage it was about 4.7v
So
I found another wall wart rated at 5.8v 1amp and I put a couple zener diodes at the other end to bring it down a couple points, google home would still keep rebooting If I removed both diodes it wont come on at all.
So
How do I go about powering the google home mini that far from the power source
Thanks
 

Reloadron

Joined Jan 15, 2015
6,593
Have you actually measured the voltage at source and at load (the device)? If the max current draw is 500 mA I would not be using a zener diode I would just place a common 1N4000 series diode in series which will drop about 0.7 volt. The device uses a mini USB connector and you are sure you have the pinout correct where you are tying in your supply?

I haven't a clue why but the normal recommended power supply is 5 volts 1.8 amp. Since you mentioned 500 mA have you actually measured the normal current draw?

Ron
 

Thread Starter

trickyrick

Joined Sep 18, 2013
43
Thanks. A google home mini can run fine on a computer USB port and I think the max is 500ma
Yes I have measured at max volume it will draw at times as high as .450a
Yes v at source was 5v at load it was 4.7 (the google home would keep rebooting)
So your suggestion is use say a 5.5v power supply and at the load add diodes until I get the required voltage.
What about a LM7805 Voltage Regulator. If I feed it with between 6 and 8 volts there should not be to much heat with drawing 5v and .400ma.
The regulator would be inside the wall
 
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Reloadron

Joined Jan 15, 2015
6,593
On average AWG 18 wire has a resistivity of about 6.385 ohms per 1,000 feet. A single pair in a 50 foot run with as much as let's overkill and say 1.0 amp will have an I * R drop of about 0.32 volt (each way) so a voltage drop with AWG 18 of about 0.64 volt. and your current as it is would be about 500 mA so the voltage drop for the run would be about 0.32 volt.

A LM7805 voltage regulator is a linear regulator having a 2.0 volt dropout voltage so it won't do anything until the input voltage exceeds at least 7.0 volts.

What I was getting at, before I considered the resistivity of your AWG 18 run was where you mentioned:
I found another wall wart rated at 5.8v 1amp and I put a couple zener diodes at the other end to bring it down a couple points, google home would still keep rebooting If I removed both diodes it wont come on at all.
Placing a standard everyday 1N4000 series diode in the line will have a drop of about 0.7 volt so if you started with 5.8 volts it would drop that to 5.1 or so volts.All of this said what you have should work with the correct mini USB connections and polarity. As long as you have about 5.0 volts going in at your load.

Ron
 

Thread Starter

trickyrick

Joined Sep 18, 2013
43
Thanks for your help.
I had one run that was longer than the 50 feet and I found that even with a 6 volt power supply and one diode when under load from the google home the voltage would drop below 5 volts. I ended up going to the dollar store and buying the 12v car chargers taking it out of the housing and that was small enough to feed through the hole into the wall. Then using a 12 volt power supply that I had already to feed that
I just don't understand y google ships out a power supply rated at 1.83 amps when the google home only draws under .5 of an amp.
I need to look for another power supply just for the google home. I have about 8 of them so I'm just gong to multiply the .5 by the 8 to figure out what I need. Actually I guess I only have to multiply .2 amps the current that the usb car charger uses
 
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be80be

Joined Jul 5, 2008
2,069
You do no that just because it said 500 mA it uses it could use up to 2 amps at times most wifi stuff does that when transmitting.
for short time.
 

Thread Starter

trickyrick

Joined Sep 18, 2013
43
Well Im under the assumption that I can only draw 500ma from a PC USB port. The google home mini works fine off of that. Im still having a problem powering the google Home on 50 to 75 of wire. When I power the car phone charger (rated at 2amp output and 5v) with 12v it will run for about 10 min and then reboot.
Im now wondering if I power the LM7805 voltage regulator with the 12v if that will make a difference
 

be80be

Joined Jul 5, 2008
2,069
500ma That continuous that's not surge
The over current protection rating is a lot higher
 
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Thread Starter

trickyrick

Joined Sep 18, 2013
43
OK then I should be able to power a USB car charger rated at 5v 2amp output on the end of 60 ft of 18 gauage wire then use that to power the google home but it still keeps rebooting
 

Reloadron

Joined Jan 15, 2015
6,593
I wonder if the long wire run is picking up noise? I just can't figure why the thing keeps rebooting? Starting to grasp at straws. Connected to a USB port it works fine as advertised. When the long wire run is added it starts doing strange things. Long as I am into grasping straws something you can try is placing a cap at the load side of the wire run. Maybe a .1uF in parallel with a 10 uF just to see if it does anything. This is based on the theory that even a blind squirrel finds an occasional acorn.

Ron
 

Thread Starter

trickyrick

Joined Sep 18, 2013
43
Maybe your on to something I know when I cut the cord on the power supply that came with google home it was one strand (+) shielded by a ground.
 

Thread Starter

trickyrick

Joined Sep 18, 2013
43
Thanks guys got it working. I purchased a brand name USB car charger at Walmart and its working fine. Not sure what the difference is between the dollar store version and the brand name version but there seems to be
Rick
 

Reloadron

Joined Jan 15, 2015
6,593
Maybe these lil' guys just like and need clean power? There is no shortage of micro-controllers out there that like to restart with noise or a tiny glitch in their power supply. Anyway, I am glad it started working for you.

Ron
 
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