Many solar inverters and charge controllers are able to transmit data in the
homes networks and if connected to a modem or router , able to send their data to remote servers .
They also may have the abillity , to add a SD-card , to log their data ; in that case , it might be advisable , to purchase a spare SDcard , since SDcards produced in future , might not be able to be recognized by the inverter anymore , because of unknown filesystem or too large size .

Most of the manufacturers offer their clients a web-interface , in which data from the inverter is displayed , and the clients are able to choose privacy settings . Some people let some of their data be visible to the public , which might be worth to check , if unsure about the energy harvest in some location .

https://www.pvoutput.org/ seems to be a non-commercial website , that offers owners of pv facillities the chance to store and visualize their data .


A producer , that had apparently withdrawn from solar inverter production , is
benning.de .

Their site for their former customers is still up , and around 150 had chosen , to present parts of their data to the public .
Overall , I like that site , it is the best of those , that I had encountered until now :
https://www.portal.benning-solar.com/site
Just click on a blue underlined location in the list .


SMA, since already mentioned, has also their customer's web-interface,
but at first glance not as easy to checkout :
https://www.sunnyportal.com/Template...PlantList.aspx
As of yesterday ( 1:49 after midnight here ) , 8188 users in the USA had made some of their their data set public viewable .