Again, in basically an open boat, a portable charger makes sense. You can
use it for other purposes as well, like charging your car battery if
you leave the lights on, or if it's a GOOD one (see below), for keeping
your batteries charged through the winter.

Yes, the boat is an open boat. But the batteries are inside the center
console, and the small door opening to the interior of the center
console is not big enough for me to easily work around. I would prefer
the connection to be kind of permanent instead of using alligator clips
of a portable charger.

Current draw at 120VAC (your "15A circuit") is not the same as the current
output TO the battery: the output is about 10 times as much (1/10 the
voltage, 10x the current, not including efficiency) So the current draw is
not a factor.

Yes, the more current, the faster the battery will charge, but you can't
use TOO much charging current: typically 1/10 the ampacity, which is about
10-15A for a Group 24.

Honestly, I don't quite understand this. I appreciate your effort in
trying to explain this to me. I figure you are saying that I don't
need to worry about what the power rating in the household power
outlet. Thanks.

Problem is, the cheap "10A" chargers don't really put out 10 amps, so some
buy the 15A instead. I'd buy a GOOD 10A "Smart" Charger, like the Xantrex
Statpower series, which actually DOES put out 10A with a proper charging
"curve". Your batteries will thank you!

Thanks for the suggestion. I will keep an note on this.

Jay Chan