chris_c
Posts: 156
Joined: Sun May 06, 2012 10:23 am

real life (aprox.) power draw - Display + kit...

Tue Sep 29, 2015 1:04 pm

So I bought one of those cheap and nasty USB power "meters" I have no illusions about its accuracy, but I reckon it should be okay as an indication only...

Connected to a single 5v 2a usb "charger" was the following equipment....

USB power "meter"
22guage good quality USB cable <--- possibly the most critical component!
Official 7" LCD
PI2 @1ghz
wifi dongle
wireless keyboad/mouse dongle

here are some peak values

Code: Select all

Amps  activity
0.65    Idle either console or X
0.75    3d Java application (as seen in attachment)
0.96    compiling an application with make -j4
0.98    compiling with -j4 AND running 3d java application
Bare in mind just how much difference a decent cable makes - with the "normal" type of USB cable I was getting the colourful square of under power on idle....
USB power adaptors frequently push out more than exactly 5v probably just to counter the state of "normal" USB cables

None of this should be taken as accurate and is only as a real world indication - posted in the hope people might find it useful and or interesting
Attachments
pi-amps-small.jpg
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gadgetoid
Posts: 152
Joined: Wed Mar 07, 2012 9:58 pm

Re: real life (aprox.) power draw - Display + kit...

Tue Sep 29, 2015 1:11 pm

These are pretty close to the results I got from my cheap bench power supply for Pi 2 + LCD.

The LCD on its own seems to eat between 430 an 470mA.

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alexeames
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Re: real life (aprox.) power draw - Display + kit...

Thu Oct 01, 2015 7:49 pm

Yep. I powered the screen separately for my measurements which were 430 mA at 5.19V, using my trusty eMeter :)

That gives us ~2.25 Watts
Alex Eames RasPi.TV, RasP.iO

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