I’m also deeply into power analysis as the way of keeping everything going. I was working with some engineering students and got them to do a spreadsheet, which I modified and added and can be used to build a budget for the power that you think you need, and what the power consumers might be. I then look for the major user of the power, and let the project be driven by that. ie if its a sensor that needs 12V and consumes a lot of power then you need to have the large battery.
I also reduce the power by changing how often it turns on the cell modem. ie from 15minutes to 60minutes. The project with students we are only talking about turning it on every 24 hours. However this is a lot of software that I’ve added to my fork.
I also have a battery threshold that I stop any transmission, and then when there is enough solar power harvested start transmitting the stored readings and then the new readings. Its not trivial software to do this, but it has now been well tested.
Happy to share more about power savings if its of interest.
One idea that I’ve seen with the Mayfly 1.0 and the new power routing, is that there can be the LiIon battery plugged in, with solar panel, and then a top up USB Battery pack plugged in.
However I do have to say that the Mayfly 0.5 and also 1.0 battery measurement is challenging, and I’ve tried to phrase it here. IHMO its a really basic issue, and has caused me no end of technical headaches. Mayfly 1.0A3 is more of problem than 0.5 https://github.com/EnviroDIY/EnviroDIY_Mayfly_Logger/issues/32