Raspberry Pi Zero e-Ink picture frame project

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Power consumption wise, this page says
Zero HDMI off, LED off 80 mA (0.4 W)
Zero HDMI off, LED off, USB WiFi 120 mA (0.7 W)

With elaboration on his blog:

Power Notes
Disable HDMI 25mA If you’re running a headless Raspberry Pi, there’s no need to power the display circuitry, and you can save a little power by running /usr/bin/tvservice -o (-p to re-enable). Add the line to /etc/rc.local to disable HDMI on boot.
Disable LEDs 5mA per LED If you don’t care to waste 5+ mA for each LED on your Raspberry Pi, you can disable the ACT LED on the Pi Zero.
Minimize accessories 50+ mA Every active device you plug into the Raspberry Pi will consume some energy; even a mouse or a simple keyboard will eat up 50-100 mA! If you don’t need it, don’t plug it in.
Be discerning with software 100+ mA If you’re running five or six daemons on your Raspberry Pi, those daemons can waste energy as they cause the processor (or other subsystems) to wake and use extra power frequently. Unless you absolutely need something running, don’t install it. Also consider using more power-efficient applications that don’t require a large stack of software (e.g. LAMP/LEMP or LEMR) to run.

For the Raspberry Pi Zero, I used all the above techniques, and here were the results:

  1. Raspbian Jessie Lite nothing besides microSD card, and ACT LED on: 100 mA @ idle
  2. Same as #1, but disable ACT LED and disable HDMI: 80 mA @ idle
  3. Same as #1, but plug in a display, keyboard, trackpad, and WiFi adapter: 310 mA @ idle(!!)

As you can see, it pays to conserve—if you don’t need it, cut it away to save power! With the Pi Zero and these power saving techniques, you can extract a lot of usage even in low-power scenarios, like solar energy or running off a battery.

I do have some basic USB power consumption measurement passthrough dongles here so I can measure it.

There’s a nice calculator here, even!!

With a really small 1200 mAh power module, I used the following values:

  • Model Zero (remember, I’ll be disabling wifi and bluetooth after development is done)
  • 1200 mAH battery pack
  • 100 mAH idle
  • sleep modes “disabled” (not sure what this means)

I get 9.6 hours.

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