Banankungen32
Posts: 13
Joined: Sun Dec 06, 2015 12:07 am

7" touch sceeen usage & power adapter

Mon Dec 07, 2015 9:49 am

So first I'm wondering if I get the 7" official raspberry touch screen will it eat all the ampere/voltage or is it cheap to run? Also I've thinked about getting a wall adapter which puts out "Output: 5V DC / 2.1A"
Will all this be safe to use? Wont ruin my Pi?
Thank you in advance.

moelski
Posts: 63
Joined: Wed Jan 09, 2013 8:16 am

Re: 7" touch sceeen usage & power adapter

Mon Dec 07, 2015 9:51 am

Hi !

I had the Pi2 und the display running at a regulated power supply.
And most of the time it uses ~1A for Pi and display.

At the moment I´m using a 2,1A supply, too. Works nicely - no problem.

Dominik

karlkiste
Posts: 184
Joined: Tue Jan 22, 2013 8:50 am
Location: berlin, germany

Re: 7" touch sceeen usage & power adapter

Mon Dec 07, 2015 11:37 am

By chance I do have it all connected up right here: a Pi B+ and a touchscreen with a seperate power supply on an (albeit cheap) power meter. The meter is connected on the line side of a switching power supply, so the current calculated for 5V is really lower than these numbers:

Display powered, but connected to a switched-off Pi: 0W (cheap meter, I said...)

Display running, displaying all black: 3.2W ([email protected])
Display running, displaying all white: 3.0W ([email protected])
Display running, backlight switched off, black image: 0.8W (~160mA)
Display running, backlight switched off, white image: 0.6W (~120mA)

edit: When the console screensaver kicks in on latest raspbian, the backlight is switched off, which is good. But the screen is also "blanked to black", which draws unnecessary current. I know that the linux console screensaver blackens the screen since the invention of the nipkow disk, but it would be great if this could be changed to white here...

Greets,
Kiste

Banankungen32
Posts: 13
Joined: Sun Dec 06, 2015 12:07 am

Re: 7" touch sceeen usage & power adapter

Mon Dec 07, 2015 3:39 pm

moelski wrote:At the moment I´m using a 2,1A supply, too. Works nicely - no problem.

Dominik
Great, exactly what I wanted, it'll run perfectly! Thank you Dominik!

Banankungen32
Posts: 13
Joined: Sun Dec 06, 2015 12:07 am

Re: 7" touch sceeen usage & power adapter

Mon Dec 07, 2015 3:41 pm

karlkiste wrote: Display running, displaying all black: 3.2W ([email protected])
Display running, displaying all white: 3.0W ([email protected])
Display running, backlight switched off, black image: 0.8W (~160mA)
Display running, backlight switched off, white image: 0.6W (~120mA)
Which means I should be ok using usb powered things as well even though im running the touch monitor & the pi
Thanks!

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