@epierre I suppose you’re right, it does better than just last through the night; with an average charge around 87% it does pretty well and can be left without worry of the battery draining.
I also checked this morning and saw that I only have a 2500 mAh battery, and not the Adafruit solar panel, but another Chinese one which gives out similar values. I plug it straight into the 7-20V DC input and it does well in direct sun. I do notice that in the afternoon it battles with indirect sun (and the blue light is not on).
I’ve put up the code I used here, it’s pretty straight forward and obviously you need to have a Thingspeak account (you’ll need to replace the XXXXXXX’s with your own key) ready to publish the data to, if that’s where you want to go.
Here is my setup on the windowsill at home :
The black and white cables come from the solar panel above.
Let me know if there is anything else you need.