I've always wished solar had a "1 panel" version that you could get/buy earlier game that might power a small trap (not blade traps, but maybe electric fence post) and also slowly charge batteries. maybe 10 W?. you can't daisy chain them.
Yeah there's a mod for it... I'm saying vanilla.
Otherwise I feel generator is OP. I feel it needs to be able to hold less gas but be able to handle a night and a day of running on a full tank. Solar feels about right in terms of power but waiting for "end game" is a bit of a stretch for solar as generators just provide so much more power.
Also: You can use solar to power a light for a 'day/night' light. Yeah, pointless in vanilla but if you mod a lot of things out of the game (like the day/time) it can be semi useful even though you can do a similar thing with the timer.