jraskell,
that sounds like a great plan, in fact it is probably the only truly sensible plan but unfortunately it just isn't going to cut it.
I have systems that need new automation due to changes and additions.
Fortunately the tasks are not that onerous and I will get away with clunky programming if I have to.
I defiantly don't have clunky as a goal or even a long term acceptable solution but if needs must it will do for now.
I just bought a couple of Nanos so I can build some simple modules, PWM charging control for the PV's being the most pressing.
Having a couple of boards to hand will allow me to keep experimenting and learning whilst one of them gets on with something important.
Measuring a voltage and a few currents whilst driving a few FET's isn't going to be taxing but I don't want to be messing with a live system that has the fate of my batteries in its grasp.