The quick setup has been done now, the wire feeding the panel's power to the controller and battery, mounted indoors.
At the moment it is just charging, so now I will have to decide what the power can be used for. I think I will go for some simple receivers used for monitoring fixed frequencies. Low power consumption, so they can run 24/7. One example is a simple receiver for the international beacon network frequency on 10m - 28.200MHz. I can probably keep the power consumption down to about 25mA for that one Very simple superhet with a 19.2MHz oscillator and therefore 9MHz IF. More on that later.
I had the idea of running a QRSS grabber with a Raspberry Pi, so I did a quick calculation for running it 24/7. I was surprised that the 50W panel with a good sized battery was only close to fulfil the requirements for full off grid operation. I will have to test the power consumption of the Raspberry Pi running the grabber software, in order to see if my estimate is too high (or, maybe, too low). The calculation includes some redundancy for several days without sunshine, buffering with the battery. Yes, the sunshine hours can be very unreliable in Denmark.
I do have some small, very low power solar panels that I will experiment with, with very low power requirement equipment, such as low powered receivers or active receiving antennas. I expect the battery used here to be Li-Ion cells, with 3 for 11V or 4 for 14V supply voltage.
More on solar experiments later.