Christine wrote:

Details: Installed a new 550 CCA Marine Battery about 3 weeks ago. Ran
great when first installed. Boat sat for 2 weeks, tried to start - "click".
Nothing. Was able to jumpstart from the truck, ran it for about 15 min top
charge. Voltmeter on the boat dashboard reads 10.5 volts. Hand-held
voltmeter at battery reads 13.98; test at alternater reads the same. Took
battery back to dealer & had tested. Battery OK, fully charged.

So, I think the alternator is OK. No visible frayed wires & such. My gut
tells me that the voltmeter in the dash is suspect since it reads
differently than the hand-helds.

Any sugggestions as to what could be draining the battery or anything else
typically to look for?

Well, your voltmeter might be suspect in terms of the accuracy of the
display, but the bottom line is that the "click" is a problem.

I've personally never had this problem, but I've help deal with this on
a friends boat -- I spent $30 for a blue sea dual battery switch and
$15 for a short battery cable and they've never had another problem. I
would strongly recommend this approach if you don't have the time to
try to track down where the drain to your battery is (I suspect your
stereo as some posters have pointed out). I would just spend $45 and
install a battery switch. The amusing thing is that a dual battery
switch (which will work fine for this application) is cheaper than a
single battery switch. A quick check on overtons.com shows the same
battery switch for $25 (check item number 70446). They don't have any
decent batyttery cables -- I've bought some great battery cables from
custombatterycables.com -- probably want the #2 or 1/0 marine version
with the ring for the switch end and whatever end you need for your
battery.

Good Luck

-Dale