Replacing alternator with solar panel array on roof?

[Mr. Previa]

That would be great! Wonder if a 12 volt panel would charge a 14v setup like that. It would be a nice trickle charge during the day while parked. Hmm, even a 12v panel has an open circuit of 18 to 21 volts. Anyone have real world, tested info on this?

[oil pan 4]

You are going to want to bump it up to a 24 volt panel and a charge controler.
"12v panels" barely charge 12 batteries, using a 12 volt panel to charge a 14 volt cell stack or pushing power onto a 14.4v system just isn't going to happen, it will be a waste of money.