The Libre Solar Project

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Energy System
#1

Hi, really glad I’ve found this project. I was wondering if devs working on LibreSolar have heard of other open projects working on the same ideas and if some “cross-pollination” was possible, to not reinvent the wheel or cause redundant development and keep best practices in a single place…

Some projects that come to mind:

I see some efforts to use LoRaWAN in the LibreSolar github (probably for panel diagnostics?), which is a really interesting idea. There was this interesting project to reverse engineer the PHY of LoRa a while ago (particularly on RN2483 and SX1276):

Some LoRa hardware also run the DASH7 protocol, which is open (unfortunatelly development seems to have stopped):

Maybe folks related to the HackRF One and GNURadio development could help giving network insights of how LibreSolar could interconnect in a more efficient way, maybe even through a meshnet like BATMAN:
https://greatscottgadgets.com/hackrf/one/
https://www.open-mesh.org/

There’s also the point of how environmentally friendly and cost effective it would be to put complex integrated circuit on every board. I don’t know if LibreSolar devs already had a discussion about that, but I think it would be important to discuss different engineering solutions that could do diagnostics of each panel (like a power optimizer / smart module), but reducing the amount of microcontrollers/pcbs needed.

Those are just some ideas that came to mind when I found LibreSolar. Thanks for your effort in making this project open to everyone. Cheers.

#2

Hi @Ataraxia,

thanks for the list. I have heard of some of them, but not all. It’s always good to see what others in the wider open source hardware community are doing :slight_smile:

Regarding LoRaWAN: We’ve used it for data transfer from multiple charge controllers to the cloud in a project for rural electrification, but didn’t get sufficient reach inside a forrest at that time. Also firmware-upgrade over LoRaWAN is more difficult than with higher bandwidth communication protocols. However, the FUOTA services will be available in Zephyr soon (PR here), so that we can re-consider it for use in the charge controllers.

Had a quick look into the DASH7 protocol. What would be the advantage compared to LoRaWAN in your opinion?

Regarding the environmental aspect: Yes, it’s a tricky decision how to make a design such that it serves its purpose with minimal amount of chips and PCB space. So far the approach was to use the UEXT connector for extension of the boards, so that you only add e.g. a LoRa chip if you need it for your use case. In the newest BMS hardware we chose an ESP32-C3 as the main MCU, which comes with lots of communication capabilities on-board. But who knows if there will still be devices that speak current Bluetooth and WiFi standards in 10-20 years, which should be the target lifetime for solar electronics?

With Open Source we can least prevent that devices become outdated on the software-side as long as the available hardware interfaces still work.

Cheers,
Martin