AXIF
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Joined: Wed Sep 23, 2020 12:35 pm

How to reduce power consumption

Mon Apr 12, 2021 9:53 am

Hi Guys,

I have developed a weather station by using raspberry pi. It is supposed to be installed in a remote area on battery (12V, 12AH lead acid).
A Solar panel (20 W) is connected with it. I have calculated my raspi zero needs .85 W and LTE stick attached to it need 1 w. So in total power consumption is almost 2W. This power consumption is increasing the cost of this project.

1. is it possible to reduce the power consumption using raspberry pi
2. If not, do we have anyother alternative to raspi?

This raspi zero is supposed to send the data on a server.

Thank you.

NotRequired
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Location: Denmark

Re: How to reduce power consumption

Mon Apr 12, 2021 10:17 am

You are not telling which Pi you are using, but you could disable modules like WiFi and Bluetooth to begin with - that should reduce power by some. If that is not enough, you could use a NodeMCU / ESP32 which uses about 50mA during average usage and it can more or less do the same as the Pi but this requires some more coding skills to get working.
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TimG
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Re: How to reduce power consumption

Mon Apr 12, 2021 10:34 am

If you don't need video output you can save ~90mW with

Code: Select all

/opt/vc/bin/tvservice -off
A Pi-zero (not a Zero-W) under light load consumes about 335mW. I don't know of any way to do better whilst running Linux, but many microcontrollers can run on far less power.

AXIF
Posts: 11
Joined: Wed Sep 23, 2020 12:35 pm

Re: How to reduce power consumption

Mon Apr 12, 2021 10:45 am

NotRequired wrote:
Mon Apr 12, 2021 10:17 am
You are not telling which Pi you are using, but you could disable modules like WiFi and Bluetooth to begin with - that should reduce power by some. If that is not enough, you could use a NodeMCU / ESP32 which uses about 50mA during average usage and it can more or less do the same as the Pi but this requires some more coding skills to get working.
I have written in the last line if you see please, i am using raspberry pi zero W.

Is it possible to bring the LTE stick in working with NodeMCU ?

Is there any GSM module that consumes less power and could be used be raspi? I have tried narrow band iot module having sim module (7020E), but its not working.

NotRequired
Posts: 237
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Location: Denmark

Re: How to reduce power consumption

Mon Apr 12, 2021 10:54 am

Raspi zero is not a specific model. What exact GSM stick are you using? There are ESP32 modules with integrated GSM module available, and the code to use is more or less also available. External GSM modules may also be used if there are libraries available for them. But all in all it depends on your project whether this is a viable sollution.

EDIT: If you want to stay in the Raspberry-verse, you could also look at the Pico Pi - I have no personal experience with this MCU yet, though..
Last edited by NotRequired on Mon Apr 12, 2021 12:14 pm, edited 1 time in total.
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drgeoff
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Re: How to reduce power consumption

Mon Apr 12, 2021 11:09 am

NotRequired wrote:
Mon Apr 12, 2021 10:54 am
Raspi zero is not a specific model.
Raspi Zero is a specific model.

And even though the OP mentioned it twice in the opening post you still wrote "You are not telling which Pi you are using".
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NotRequired
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Location: Denmark

Re: How to reduce power consumption

Mon Apr 12, 2021 11:16 am

drgeoff wrote:
Mon Apr 12, 2021 11:09 am
Raspi Zero is a specific model.
So is Zero-W but the two are not alike. I asked to be sure, sorry if I offended you by doing so.
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AXIF
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Joined: Wed Sep 23, 2020 12:35 pm

Re: How to reduce power consumption

Mon Apr 12, 2021 1:06 pm

NotRequired wrote:
Mon Apr 12, 2021 10:54 am
Raspi zero is not a specific model. What exact GSM stick are you using? There are ESP32 modules with integrated GSM module available, and the code to use is more or less also available. External GSM modules may also be used if there are libraries available for them. But all in all it depends on your project whether this is a viable sollution.
I think its a great idea using this esp32. Would be a challenging but let me give a try. At the moment i am using Huwawe LTE stick 3531 with my raspi zero w. but it takes a lot of power (1W)

Thank you for support man :)

NotRequired
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Location: Denmark

Re: How to reduce power consumption

Mon Apr 12, 2021 1:25 pm

Just make sure that whatever GSM module you select, it must be supported by the GSM grid and there must be a library available for it. Your Huawei modem is not gonna be easy (if at all possible) to interface from ESP/PicoPi or alike.
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Heater
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Re: How to reduce power consumption

Mon Apr 12, 2021 1:54 pm

I think that whatever you do that GSM modem will be consuming a lot of your power. About 1 watt. So even if you get the consumption of your compute device, Pi or ESP or whatever, down to zero you are not doing very well.

What to do? I'm going to assume you don't need full speed, or any communication, all the time. You only need to send weather data once a day or one an our or so.

1) Does your GSM modem have a low power or "sleep" mode you can set it to so as to save power. I have no idea if there is such a modem but it's worth checking.

2) If not you could arrange to switch its power on and off. With a relay or preferably a MOSFET to save power.

3) Or use a different communication medium. The LoRa wireless system was designed exactly for this kind of low power, low data rate communication. There are all kind of LoRa modules you can get today. Google "LoRa Raspberry Pi" or some such for further info.

Switching out a Pi for a low power micro-controller, like a Pico or ESPxxx, and using LoRa would reduce you power consumption by a factor of about 100.
Memory in C++ is a leaky abstraction .

pidd
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Re: How to reduce power consumption

Mon Apr 12, 2021 2:17 pm

Setting to 2G instead of 3G could save a lot of power depending how much data is sent and how often.

Moonmarch
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Re: How to reduce power consumption

Wed Apr 14, 2021 9:40 pm

Adjust the computer clock speed, graphics processor clock speed, and reduce the RAM speed in config.txt the Raspberry Pi Operating System. If you do not need the Raspberry Pi Zero to run at full clock speed, then reduce the clock speed to a lower frequency. Disable the Raspberry Pi Zero on board WiFi, and Bluetooth modules. The Raspberry Pi Zero will use the least amount of power compared to the main Raspberry Pi Computer models. The Raspberry Pi 3 A+ does not use as much power compared to the main Raspberry Pi computer models.

cleverca22
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Re: How to reduce power consumption

Thu Apr 15, 2021 3:51 am

Moonmarch wrote:
Wed Apr 14, 2021 9:40 pm
Adjust the computer clock speed, graphics processor clock speed, and reduce the RAM speed in config.txt the Raspberry Pi Operating System.
when i was doing some testing on my pi0, i found that clock speed had very little to do with tempurature (which is a side-effect of power usage)
the critical factor, was instead the core voltage

but, if you set the clock speed to the lowest option via cpufreq, the firmware will drop the core voltage, which can lead to you thinking slower freq means lower power

config.txt does also have options for under-volting, and you will need to underclock more if you go too low

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