On Sun, 13 Nov 2005 20:23:38 -0800, jaykchan wrote:

I would like to know what are the benefits of using an onboard charger
instead of a portable charger.


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.

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.

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!

Lloyd Sumpter
"Far Cove" Catalina 36 c/w onboard Xantrex 40A