Yes. I do it. I trickle charge the battery from a 14v to 48+v converter while I ride, giving me about 5 to 10 miles of additional range. This also helps ensure I can make it up the final 500+ foot hill to my home. You could do the same (more or less) with solar panels. There is even a solar panel charge device specifically for higher voltage batteries, which you might have to look around online for. (I don’t have one.) The difficulty is carrying enough solar panels to make a difference. Also while you are riding your panels won’t be in optimal orientation. I would expect maybe 1/3 of rated power, so a 50 watt panel might provide 15 or 20 watts, more if you are stopped and orient it to the sun. I used an average of about 150 watts during my lengthy ride today, so adding solar at 15 watts would have added a theoretical 10% to my range. Let us know here if you try it and what you learn.