General question on battery backup and solar panels

Sixfab Power HAT & Software Power Management & UPS HAT
1

Hi all,

I’ve got a specific project for a sensor network and we are going to need a power supply for the sensors. Each sensor has three or more Pi 4Bs, drawing around 5w each. Right now we are experimenting with Jackery Solar Generator 300s and they seem to more or less work. The Jackerys aren’t rainproof and aren’t really made for standalone use (these sensors need to be continuously online).

We are wondering about a custom solution that would have the following features:

  • Expected power draw is 15-20w. However, sometimes it might be quite a bit less and we don’t want to be bit by any auto-shutoff function (the Jackery system automatically shuts power off after it is below 10w for six hours). Future designs might draw much less power.
  • 300wh-500wh battery. Ideally we could swap out batteries for different sites and different applications.
  • 100w solar panel.
  • A software interface (probably over USB) to get the battery charge status and how much power is coming from the solar panels.
  • We’d want this system to run fine in the field for 4-6 months.
2

Hello,

I essentially have a system running like this in my field research trailer (am an ecologist). In my case it is a bigger system (156 Ah / 2000 wh battery and 210 watt solar), but it continuously runs 2 raspberry pi’s (one with Sixfab’s modem/hotspot and one with Victron’s VRM solar & battery monitoring). I wrote up some how-to’s on the tiny trailer forum that could help you.

Building a DIY LiFePO4 battery:
https://www.tnttt.com/viewtopic.php?f=30&t=74022

Setting up the 2 Raspberry Pi’s for battery monitoring:
https://www.tnttt.com/viewtopic.php?f=30&t=74325

My trailer build thread is referenced in both threads above if you want more info.

The battery size you mentioned above would work fine. Mine is bigger because it also runs computers and other electronics when we are in the field, along with the all important coffee grinder!

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