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Zero4U power consumption

Posted: Fri May 04, 2018 4:07 pm
by lianergoist
I have just bought a Zero4U usb hub. The card works fine, but it use some power. Without devices connected it use almost nothing, but with a mouse or keyboard connected, it use far more beyond what the mouse / keyboard draws.

Raspberry Pi Zero + Zero4U without mouse / keyboard (idle) = 0.5W
With mouse or keyboard (> 100mA) connected = 0.9W!

I just think it's worth paying attention to ...

Re: Zero4U power consumption

Posted: Fri May 04, 2018 4:40 pm
by Paeryn
lianergoist wrote:
Fri May 04, 2018 4:07 pm
Raspberry Pi Zero + Zero4U without mouse / keyboard (idle) = 0.5W
With mouse or keyboard (> 100mA) connected = 0.9W!
Long time since I did electronics but 100mA at 5V = 0.5W. If you plug a device in rated at more than 100mA and the power usage is going up by 0.4W that shows it is drawing less than 100mA.

Re: Zero4U power consumption

Posted: Fri May 04, 2018 4:45 pm
by bensimmo
It does have to power the electronics and hub chip too.

Re: Zero4U power consumption

Posted: Fri May 04, 2018 7:57 pm
by asandford
lianergoist wrote:
Fri May 04, 2018 4:07 pm
With mouse or keyboard (> 100mA) connected = 0.9W!

I just think it's worth paying attention to ...
If running on batteries, then maybe, but

If my maths is correct...

There are 8760 (365 *24) hours in a year.

0.9 * 8760/1000 = 7.884kWh/year

My unit (1kWh) price for leccy is 15.48p, so this costs £1.22 to run for a year?

Feel free to point out any mistakes

Re: Zero4U power consumption

Posted: Mon May 21, 2018 9:44 am
by rin67630
Your hub is OK. Mine has the same behaviour.
The USB modems need ~15 -25 mA power on both side. They are usually smart and go idle when nothing is connected, saving power.

Ideally the RPi Zero should be used headless for tasks that require "always on".
VNC Viewer is the the most convenient way to use it, so you won't even need a keyboard and a mouse and mainly no USB hub as well.
You connect the periphery just to setup the WLAN. Then you remove the hub.
You just operate in a Window of your computer, when you need to operate it.