solar power for a pi

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natenatenate
 
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solar power for a pi

Post by natenatenate »

Hi!
I'm really new to this, but I have a sculpture that I'm putting a pi inside of and I want to power it with 5 small solar panels that are on adjustable arms.
Can I wire together 5 of these panels
https://www.adafruit.com/product/3809
in parallel using this charger
https://www.adafruit.com/product/4755
and this battery?
https://www.adafruit.com/product/354
or is there another approach you would recommend?
Thanks so much!
Nate

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sj_remington
 
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Re: solar power for a pi

Post by sj_remington »

Please state the RPi model and all power consuming accessories. RPi's are power hungry compared to other microprocessors.

Those panels would perhaps put out enough to power a small RPi in full sunlight, but certainly not indoors.

The system as imagined above will not tolerate frequent, unplanned power outages, brownouts or long periods of darkness, so you will need to very carefully consider battery capacity and/or other backup power to maintain semi-continuous operation.

My initial impression is that it will be difficult and require some expertise to make such a system work with the RPi.
Last edited by sj_remington on Mon Sep 19, 2022 4:19 pm, edited 1 time in total.

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natenatenate
 
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Re: solar power for a pi

Post by natenatenate »

Thanks SJ. It a RPi 4 model B. It will hav a RPi v2 camera on it and a motion sensor.
I totally recognize that this will require some expertise, but I'm def willing to put in the time and energy.
Would upgrading to a larger panel make more sense?
These are out of stock but the dimensions would be fine.
https://www.adafruit.com/product/500
The piece will be in a bright, south facing window, not outside.
Continuous operation is not a requirement: for it to stop working w/o sun and start working w/ sun is actually desirable as long as I can power up and down without damaging the RPi.

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sj_remington
 
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Re: solar power for a pi

Post by sj_remington »

For the RPi 4 and peripherals, plan on the solar panel and battery backup providing 10-15 W, minimum during operating hours, at location. The panels you linked put out less than 0.2 A each in full sun (1 W maximum). Keep in mind that solar panels are rated for full sun at noon, so for an indoor location, you will need to conduct power tests in order to choose an appropriate setup for typical year-round operating conditions.

For safe and graceful system shutdown and startup, you probably need some type of smart supervisor circuitry, perhaps a separate microprocessor. I have not done that for an RPi and have no recommendations.

I suspect that if you describe the functions that the RPi and system are supposed to carry out, a much more energy efficient system can be suggested.

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natenatenate
 
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Re: solar power for a pi

Post by natenatenate »

Fantastic, thanks!
Actually, please forget the camera, I'll offload that to a different piece that actually plugs into a wall.
To simplify things, all this piece will need to do is push and pull files (jpgs) from a repository online somewhere based on specific conditions, and do some of processing of the files locally before it pushes them back up to the repository.
Gracefully powering up and down is a requirement, so I will start looking into that too.
So it is true there probably is a much more lightweight approach!
Thanks for any suggestions!
One catch: I really do want 5 separate panels that I can position, as that is part of the actual physical aesthetic of this thing.

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sj_remington
 
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Re: solar power for a pi

Post by sj_remington »

Consider the ESP32-CAM (or its camera-free relatives). It is computationally quite powerful, has built in WiFi, considerably less power hungry than the RPi, and it does not depend on a failure-prone SD card for the operating system, so it would tolerate frequent shutdowns.

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natenatenate
 
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Re: solar power for a pi

Post by natenatenate »

Thank you! Checking it out.

Yikes. That may actually be beyond my capabilities. But at $4 maybe I'll buy one and give it a go!

"For advanced users only! This product is just the module - which can be difficult to use. You'll need to solder it onto a board with supporting circuitry. This module is for developers at this time.

Please note this product is for people who are comfortable compiling via the ESP IDF toolchain. There are the beginnings of an Arduino IDE setup and a CircuitPython port. We are providing these for the community of advanced hackers, coders, and makers who are willing to help make demos, projects, and tutorials for the ESP32-S2!"

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sj_remington
 
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Re: solar power for a pi

Post by sj_remington »

I'm not sure what product and tutorial you are looking at, but I bought a couple of ESP32-CAMs on eBay and worked through several tutorials on https://randomnerdtutorials.com/ and this https://github.com/alanesq/esp32cam-demo as well as others in the "alanesq" repository.

Those tutorials are really good and I encountered no technical problems whatsoever. It is pretty much like programming Arduino, and vastly simpler than RPi/linux (which I've used for many years).

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natenatenate
 
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Re: solar power for a pi

Post by natenatenate »

cannot thank you enough. i'll order one and poke around.

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