how to log and graph battery (cell) voltage over time?

[affinite]

Thanks for your pointers. Your 'How I did it' would be most useful.

I get the general idea of the hardware bits, but it is the fine details that I can'ts seem to work out, e.g 'data is updated every second but, in addition, the data is sent every 10 minutes over the internet to my home' - where and how do you program or define those intervals? Stuff like that.

I am sure there is all sorts of fine tuning and cool stuff I could do, but unfortunately it would take me a lot of time to learn all this to be able to tweak what others have done. I have already spent too many hours searching the forums on this. Hence my wish for a step by step 'recipe' that I can just blindly copy. So, if you are willing to do your 'how I did it' that would be fantastic. No rush - with COVID I am currently a long way away from my boat.

Noel

I too have some time on my hands so I'll get to it.
In the meantime if you wanted to follow the same route as me take a look at the wiki for the firmware I'm using on the ESP8266 Microcontroller and also Google and get familiar with Node-Red 
I'll be back