And why is that? Do I have to disconnect my solar panels when I run the
engine?

Assuming you have a photovoltaic charge controller, ordinarily not. AFAIK. As
an unaplogetic ol'stinkpotter, I'm not extremely well acquainted with solar
panels. You would be better prepared to discuss them than I.

Beyond that, I'm not interested in firing up another anal retentive ****ing
contest of dueling websites with you, Jeff.

If you have a contrasting opinion that it is advisable to run the battery
charger and the alternator at the same time, please present it.