I am moving gradually to a situation where my small electronics, typically a cell phone, lights, and GPS, are all field rechargeable, either from each other or from a power bank which on extended projects or trips could be replenished by a solar panel, if no other source is available.

I say lights, because I go by the traditional caver's dictum of three separate light sources. Almost always I have at least a light, typically a headlamp of some sort, and a smaller backup.

Since the typical power bank incorporates at least a small LED, there is no reason to sit around and curse the darkness.