Solar Panel for Sigfox

Yes but voltage regulators are usualy a good waste of power. In such a case I would prefer a DC-DC converter which are closer to 90-95% performance. Anyway I was looking for something more compact if possible to save boards and wiring. I've seen forums stating that the +3V green plug works well with >3v but I don't really know if that's safe and how much more than 3v I can try