RPIZW
Posts: 16
Joined: Sat Sep 28, 2019 5:54 pm

Pi Zero vs Zero W - power consumption (or A+?)

Sun Sep 29, 2019 4:05 pm

Hi everyone,

I hope my question won’t make you mock me, I know it might sound a bit silly

My need from the device:
1. VPN server (any) [Or as STS]
2. Less power consumption as possible
3. Low heat (but it’s not the most important)

I currently have Pi zero W, very satisfied! Brilliant device.

Will Pi Zero (not w) use low power consumption if I connect it to the network using micro-USB to Ethernet adapter?
Did someone tested it?

Or else someone is aware for a device with ethernet only and is lower consumer than Pi ZeroW?

Thanks in advance

ejolson
Posts: 3828
Joined: Tue Mar 18, 2014 11:47 am

Re: Pi Zero vs Zero W - power consumption (or A+?)

Sun Sep 29, 2019 5:59 pm

RPIZW wrote:
Sun Sep 29, 2019 4:05 pm
Hi everyone,

I hope my question won’t make you mock me, I know it might sound a bit silly

My need from the device:
1. VPN server (any) [Or as STS]
2. Less power consumption as possible
3. Low heat (but it’s not the most important)

I currently have Pi zero W, very satisfied! Brilliant device.

Will Pi Zero (not w) use low power consumption if I connect it to the network using micro-USB to Ethernet adapter?
Did someone tested it?

Or else someone is aware for a device with ethernet only and is lower consumer than Pi ZeroW?

Thanks in advance
I would not expect a Pi Zero with a USB Ethernet dongle to use more than a Pi Zero W with active WiFi. It will also make some difference whether you use a 100 Mbit dongle or a gigabit one.

Network performance numbers for a WireGuard VPN on a Pi Zero over a gigabit dongle compared to other models of Pi are at the link

https://www.raspberrypi.org/forums/view ... 9#p1533989

Unfortunately, I didn't perform any power consumption measurements.

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rin67630
Posts: 613
Joined: Fri Mar 04, 2016 10:15 am

Re: Pi Zero vs Zero W - power consumption (or A+?)

Sun Sep 29, 2019 7:05 pm

RPIZW wrote:
Sun Sep 29, 2019 4:05 pm
Will Pi Zero (not w) use low power consumption if I connect it to the network using micro-USB to Ethernet adapter?
Did someone tested it?
The question is absolutely not silly! Low power is an essential characteristic of IoT.

I did test it.
The Pi Zero can use as less as 80mA... until you use USB.
The 100mBit USB to Network converter I have tested used about additionally 35mA and brings your Pi to about the same power requirement than an Pi ZW in a nearby Wifi connection. That was with the USB to Network converter as only USB device, with a 4-chanel hub you have got another 30mA more.

So according to my tests the PiZW used at near range without any periphery is the power champion if you need networking.
You probably may further reduce the power draw by setting the WiFi chip to low power, but I did not do it yet.

alphanumeric
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Joined: Tue Jan 19, 2016 2:17 pm
Location: Sydney, Nova Scotia, Canada

Re: Pi Zero vs Zero W - power consumption (or A+?)

Sun Sep 29, 2019 7:33 pm

The A+ does not have WIFI, so I would expect it to be similar to a Zero with USB ethernet. It does have a full sized USB port though.
The 3A+ has WIFI but is going to use a fair bit more power.
https://www.raspberrypi.org/documentati ... #pi-power

I use this with my Zero's
https://shop.pimoroni.com/products/thre ... connector
And this with my A+'s
https://shop.pimoroni.com/products/usb ... an-adaptor

I only ever use the Ethernet jack for setting up my Motion Eye cameras though. When possible I use WIFI.

RPIZW
Posts: 16
Joined: Sat Sep 28, 2019 5:54 pm

Re: Pi Zero vs Zero W - power consumption (or A+?)

Sun Sep 29, 2019 7:51 pm

Thanks!

I’d definitely use 100mbps as it’s smaller consumer than 1Gbps

So if I understand correctly
- Pi Z idle with 100Mbps = 115mA

- Pi Z W idle using wifi only = 115mA
While low power wifi expected to be lower

The type of traffic will definitely make difference, wifi will consume more to decrypt, but I don’t mind. I only care about Idle

I wonder now..
I have a Juniper PoE switch (I love JunOS)
How much Pi zero will take with the below PoE splitter

I hope someone have tested or can do :)

Image


By the way, the Pi zero have the same processor as Pi 1B. So how come zero runs as 1Ghz? Overclock?
If so, is there a way to change it back to 700Mhz as it comes with?

W. H. Heydt
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Location: Vallejo, CA (US)

Re: Pi Zero vs Zero W - power consumption (or A+?)

Sun Sep 29, 2019 8:47 pm

RPIZW wrote:
Sun Sep 29, 2019 7:51 pm
By the way, the Pi zero have the same processor as Pi 1B. So how come zero runs as 1Ghz? Overclock?
If so, is there a way to change it back to 700Mhz as it comes with?
Over the manufacturing life of the BCM2835 (the SoC used on the Model B, Model A, B+, Pi0, Pi0W, CM) enough SoCs tested good at 1GHz to use only 1GHz parts on the Pi0 and Pi0W. You can, naturally, underclock a Pi0/Pi0W to 700MHz if you so desire.

ejolson
Posts: 3828
Joined: Tue Mar 18, 2014 11:47 am

Re: Pi Zero vs Zero W - power consumption (or A+?)

Sun Sep 29, 2019 10:20 pm

RPIZW wrote:
Sun Sep 29, 2019 7:51 pm
Thanks!

I’d definitely use 100mbps as it’s smaller consumer than 1Gbps

So if I understand correctly
- Pi Z idle with 100Mbps = 115mA

- Pi Z W idle using wifi only = 115mA
While low power wifi expected to be lower

The type of traffic will definitely make difference, wifi will consume more to decrypt, but I don’t mind. I only care about Idle

I wonder now..
I have a Juniper PoE switch (I love JunOS)
How much Pi zero will take with the below PoE splitter

I hope someone have tested or can do :)

Image


By the way, the Pi zero have the same processor as Pi 1B. So how come zero runs as 1Ghz? Overclock?
If so, is there a way to change it back to 700Mhz as it comes with?
To set the processor speed to 700MHz edit the file /boot/config.txt as root, read the comments, make the change and then reboot.

RPIZW
Posts: 16
Joined: Sat Sep 28, 2019 5:54 pm

Re: Pi Zero vs Zero W - power consumption (or A+?)

Mon Sep 30, 2019 8:04 pm

It says it's 700 Mhz default - but it's not. it's 1Ghz
#uncomment to overclock the arm. 700 MHz is the default.
#arm_freq=800

I reduced it to 700Mhz, don't see the power reduced.. I hope that my USB tester is ok :D

RPIZW
Posts: 16
Joined: Sat Sep 28, 2019 5:54 pm

Re: Pi Zero vs Zero W - power consumption (or A+?)

Mon Sep 30, 2019 9:04 pm

Ok test results (I hope it will help someone..)

Pi Zero W 700Mhz test
Idle: 0.10A, 38.5'C
during encrypted download/upload: 0.15A-0.2A 40.0'C

Pi Zero W 1000Mhz test
Idle: 0.11A, 39.5'C
during encrypted download/upload: 0.18A-0.25A 40.0'C

boot time is the same on both

Funny thing is, when the CPU configured as 700Mhz, then the download is noticeable faster. I repeated the test many times to confirm it and the result were the same (testing locally not through the internet)

My conclusion is that the overclock the Pi Zero W comes from factory, is not doing so good -- or at least not from networking point of view.
what do you think?
btw sorry I don't have more accurate multimeter

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Imperf3kt
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Location: Australia

Re: Pi Zero vs Zero W - power consumption (or A+?)

Mon Sep 30, 2019 9:31 pm

To see any power benefits from underclocking, you may have to undervolt as well.
Be aware that going too far will make the system unstable and crash.
It's likely a tiny amount though, not easily measurable or worth the effort.

The config.txt file says the default us 700MHz because it is on the first Pi model (used to be 600) and the config.txt file needs to work across all Pi models.
55:55:44:44:4C
52:4C:52:42:41

RPIZW
Posts: 16
Joined: Sat Sep 28, 2019 5:54 pm

Re: Pi Zero vs Zero W - power consumption (or A+?)

Mon Sep 30, 2019 10:04 pm

I don't know how to play with the voltage and don't even know how much to reduce.
The little I know is that
vcgencmd measure_volts
volt=1.2000V
Anyway, how come without playing with the voltage I can still see some difference?

RPIZW
Posts: 16
Joined: Sat Sep 28, 2019 5:54 pm

Re: Pi Zero vs Zero W - power consumption (or A+?)

Tue Oct 01, 2019 10:51 am

ok I found out the list below
then if I'm not wrong, if I underclock to 700Mhz, then below configuration will be safe?
over_voltage=0


is it possible to play with the GPU as well? (i have no need for gpu, hdmi disabled)

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