According to mm :
I don't think a 650 CCA battery puts out 650 amps at one time.
Everything would melt.

It _can_, more or less. Whether it'll melt is up to how you've
connected it.

To the OP, I don't think it is called a converter unless it goes from
DC to AC. From AC to DC it is called a rectifier, even if that is
only part of it.

The OP is using informal terminology. "Converting 120VAC to 12VDC"
is what he's trying to do. A rectifier converts AC to DC, but without
a voltage change.
--
Chris Lewis,

Age and Treachery will Triumph over Youth and Skill
It's not just anyone who gets a Starship Cruiser class named after them.