Hi. When you say "not 100%" what does that mean exactly? I would be curious to hear if you can build a solar panel and see if it produces electricity all the time.
The "Always Day" setting is re-applied to the whole world whenever a player goes to "Settings->Mod setting" inside the game and changes the setting there. Try Turning it on and off :-) ... the good old windows advice :D
There is also a third thing I thought off, and that is if you are using a mod that changes the order of the Layers of the world map, the always day setting will not be applied to the "main world".
Let me know.
Kind Regards
Themightygugi