@luandro did you make progress with this?
I’m looking to build a complete system for around £30.
8w solar £10
Esp32 £10
Sd £5
Waterproof case £5
Direct solar power, no battery. It only works when sunny.
The esp32 boots OK from solar in my tests.
A comparable pi system would be nearer £100 due to the larger panel and requirement to have a battery.
But didn’t get it working yet.
My content including Android apps is https://rosettaphone.org
@sam_uk since I bought the wrong boards I didn’t make any progress. Found a blocking bug when trying to manually connect sd modules.
Ideally I’d want to try with these ESP32-WROVER-B, which comes with a card-reader. But then, as others mentioned, they’re in the same price range as 256mb of ram orange pis. Worth checking if esps are worth it energy-wise.
Rosetta phone project is really awesome, although not relevant to the communities I work with. But a good inspiration.
I would not recommend solar only, no battery. A small battery, or even a 'Ultra / Supper capacitor ’ will provide stability if the solar panel is not in full sun or is shaded for a moment (bird, cloud, someone moving the setup, etc…
I would consider expanding your idea a bit. You are going to have some relativity fixed costs. A solar panel, charge controller, enclosure. If it is going to be a ‘fixed’ installation you may need hardware for attaching to a building or pole vs something that is placed outside as needed and secured afterwards. If you first focus on a ‘base’ project, that is the enclosure, solar cells, etc you can later swap out the computer side of things as needs changes or better devices become available.
Batteries are all around us if you know where to look. Old laptops and mobile phones are good sources if you have access to basic tools to take them apart.
About the Orange PI, I found this: In idle, the board draws about 200mA. the power consumption jumps up to about 450mA
Even a 1 watt panel and a very small battery for stability and peak vs idle power usage should be enough. Some cheep solar lights have everything you need. For ~$5 you could have weather rated enclosure, solar panel, battery, and charge controller. 2021 New Style Outdoor P65 Waterproof 120 Lighting Angle 56 Led Outdoor Wall Mount Solar Powered Security Lights - Buy Led Solar Light Outdoor,120 Lighting Angle 56 Led Solar Outdoor Garden Lighting,Outdoor Ip65 Waterproof Motion Sensor Solar Spotlight Flood Light For Road Garden Garage Product on Alibaba.com
Once the led pane is removed you often have lots of room for your project.
@Spor7biker @luandro thanks. I should have mentioned I include some super caps.
That orangePi does look good. I like that it’s open hardware too. Early reviews suggested the software was underdeveloped/ crashy. Do you know if that’s improved over time?
I wonder if anyone has done a LoRa hat for it, could bring us back to Meshtastic 
My experience is that it is always the battery that fails in small solar systems. Particularly when exposed to +40c in enclosures. Managing batteries properly requires decent electronics which adds cost. Cheap systems may work adequately for a week or two, or maybe even a month or two. This solar setup I did a couple of years ago worked OK (including the <0c temps we get in the UK)
If you want something that works reliably for years I think you either want simplicity or expensive components.
Solar is never as good as it looks on paper, add a layer of dust to half capacity. There’s more cloud than you think etc. My rough rule of thumb is to look at what works on paper, then roughly quadruple it. Solar is fairly cheap these days. Certainly compared to my time.
It seems Armbian doesn’t support the A5 there’s some third party builds but everyone seems to complain about the Wifi.
£15 Orange Pi Zero 2 seems better supported
I have a Orange pi Zero 1 lying around, I just stuck Armbian on it and getting 0.17amp draw. I’ll try sticking Piratebox & some content on it.
I’d look into Internet in a Box: https://internet-in-a-box.org/
It sounds like exactly what you are looking for.
I’d forgotten about IIAB, I’ll take another look. The Ansible stuff scares me slightly.
I did make some progress on a £20 OrangePi Zero & piratebox code. I Got captive portal/fileshare/ssb working on it. Notes here. There are SSL problems on some browsers though.
Check out also, to boot from via SPI flash (if your board has a chip)