It can be done, I have done it just for the sake of playing around. The voltage needs to be fairly consistent so the solar panel needs at a minimum a voltage regulator and the ideal would be a solar charger on a battery which is connected to the safety connector.
These are the two things I used to do this plus a battery from ACE used for kid's ride-on toys. American Reef Channel has a video on Youtube on how to connect Tunze products to batteries. Watch my youtube channel, Mitch Powers Reef, I'm doing a video on this solar panel subject.