Charging / Voltage Issue

[JKIPS]

I have a 2001 Waksetter, 5.7L Hammerhead.

Here's the situation

1) Both Batteries Excellent and Charged (wired on a 1 / 2/ off / all switch with one battery wired hot for the stereo so that I turn the batteries to off when boat is parked on a sand bar or shore for the day and the stereo is on and then switch to all while running)

2) Alternator Excellent

Start on the water Fri, On dash Digital Voltage meter reads between 12.2 and 12.5 and slowly drops .1 or .2 over the course of a day.

Next day, On dash meter reads 12.0 and over the course of the day stays relatively the same bouncing between 11.8 and 12.0 end of the day it may read as low as 11.7.

What would cause this -

Would a bad Ground Connection Cause this?

Should I replace my belt or try and tightent the belt?

Thanks for any input

[shawndoggy]

my unscientific approach:

1. Check all connections. Make sure ground and power runs are corrosion free and tight. make sure battery posts are clean and terminals are tight. Make sure runs from switch to house circuit are clean and tight.

2. Charge batteries. Make sure voltage reads at least into the high 13s when the boat is running at speed. if it doesn't, repeat #1, and then

3. Get batteries load tested, if OK, then

4. Get alternator load tested.

[bnew03xti]

Your problem might be having your switch on "all" while the boat is running. The alternator is not meant to charge 2 batteries at once, so I hear. While your boat is running you should only be switched to "1" or "2", alternate them every other outing. With the engine running your voltage regulator should be charging the batteries between 14 and 14.5 volts, if it's not reading that on your gauges with the engine running you have an alternator problem.