I would like to have solar panel, accumulator and Arduino in one circuit. I am having a solar panel of 13,71V/10W and a gel accumulator rated 12V/7.2Ah (this solar panel is dedicated to this accumulator) so there is that. I can easily charge this accumualtor with this solar panel as there is a regulator attached to solar panel (voltage is fixed - it is always 13,71V). Additionally I would have 12V->9V regulator just for an Arduino but that does not matter here.
Here I am wondering, how can I put Arduino in the same circuit. As long as I know, I can not charge and discharge accumulators at the same time. How could I make this work so I could have all of them in one circuit? Would I need a special solar charge controller? Could I overcharge my accumulator without additional circuit between solar panel and accumulator?