I generally don’t look at the username or other details of a poster’s presence when replying; I stick to the “content of their [text] character[s]”, to paraphrase MLKjr. This can cause me to waste time casting pearls before known swine.
So I didn’t realize that the post was by a daydreaming pothead who frequently bombs half-baked ideas at us in /r/vandwellers. This particular one didn’t seem as moronic as usual (only confused and overconfident) so I engaged. It had the title: “How often do you drive your van? I think solar is a luxury. I’m thinking driving to work and to buy food ect is going to be plenty of time for the alternator to recharge 4 deep cycle batteries. Instead of having solar you could recharge with a system your van already has.”
So here’s what I wrote before I realized s/he probably wouldn’t even remember writing it later:
Solar charging and alternator charging are different beasts that [work better together](http://rvwiki.mousetrap.net/doku.php?id=electrical:12v:alt_and_solar) than either do separately. Solar isn't mandatory if you can plug in [a smart converter](http://rvwiki.mousetrap.net/doku.php?id=electrical:converter) at work a couple times a week to get the bank [fully charged](http://rvwiki.mousetrap.net/doku.php?id=electrical:12v:charging). People who want to charge from alternator _only_ would be wise to look at lithium or carbon-foam chemistries which don't care about partial stage of charge (the scenario you presented). Lead batteries [die early](http://rvwiki.mousetrap.net/doku.php?id=electrical:batterycide) from [partial charging](http://rvwiki.mousetrap.net/doku.php?id=electrical:12v:psoc).