Posting here as I cannot find any reason or explanation in any other reported posts, but stock KSP solar panels are listed as producing EC and 0 MJ but produce, as best i can tell, about zero EC.
I am not sure if this is KSPIE or another mod doing this, but KSPIE isn't supposed to modify much at all about stock parts, so I'm at a loss as to why this is happening. As it is, you cannot setup any early relay satellites (let alone probes) because your solar panels simply do not work. This makes playing career mode with KSPIE effectively impossible (and even in sandbox, forces you to put nuclear power on even the smallest satellite, which is rather absurd). I'm not convinced it's KSPIE actually causing this, but I can't figure out what might be otherwise doing it. So far as I have been able to find, other people have reported this but havent gotten any answers, solutions or follow up apart from other people saying they also had this cropping up.
editing to clarify--some years back in this thread, it was stated KSPIE does interact with the stock gigantor panels, but my post is about the basic 1x1--neither this, nor any other solar panels generate ANY EC at all so far as I can tell (tested in sandbox with a variety of simple satellites and probes).