posted 03-15-2010 10:15 PM ET (US)        

"The only drawback that I can see to the arrangement I just described might be the chance that a very small reverse current flow though the charger would very slowly discharge the battery over long periods when the boat was idle but the charger was not powered ON. A very small reverse current flow from the battery back through the charger could, over a long period (perhaps six months), reduce the charge on the battery. Other than this, I do not see any drawback."

I have, as well as the previous owner, been plagued with the problem of the house battery constantly discharging in a short term layup of the boat. I could never track down the reason as the "parasitic" draw to the boat was too low to cause a drain on the battery like I was seeing.

After reading your sidebar on battery connections last week, a flag went up. I decided to disconnect the hard-wired charger after bringing the battery up to a full charge state. I checked the battery voltage loss after a week and to my surprise the voltage remained at 12.72.

Typically, the voltage would have dropped to the low 12's and 12 volts even by 2 to 3 weeks. Drove me crazy.

This permanently mounted charger has been more trouble then the the price the previous owner paid. It will be replaced this season.

Thank you Jim for the food for thought.
Joe