Power During Long Absence

[leisterf]

When leaving Puff at the dock for a few months, is it better for the batteries to leave the shore power attached and on or is it better to disconnect it to reduce galvinic action?

Re and Frank Puff #691

[jentine]

For the past five years, I have kept a boat in Florida.  When I go down, I call the marina and have them put my boat in the water and make it ready for my use.  I have been plagued with dead batteries.  They would recharge them and they lasted for the week I would be there.  Last year I replaced the batteries and added small solar chargers.  The mechanic at the marina was surprised by the performance.  He told me that regardless of the period of my absence (which ranges from 8 to 16 weeks), the batteries are fully charged when he puts the boat in the water.  It starts with no effort other than turning the key.  
I would suggest that you disconnect the shore power, go to one of the marine discount houses, purchase a solar charger for each battery (they cost about $37), install them and visit the boat occasionally during the winter to check it.
Jim Kane

[Stu Jackson]

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by jentine:
                              I have been plagued with dead batteries.  Last year I replaced the batteries and added small solar chargers.  The mechanic at the marina was surprised by the performance.  ...the batteries are fully charged when he puts the boat in the water.  Jim Kane<HR></BLOCKQUOTE>
 

Frank

Your choices are not only to leave it connected or disconnected to shorepower, but rather the question should be:  "What is one of the best ways to reduce or eliminate the self discharge of the batteries when you are away from the boat?"                          

Ron's right about the shorepower, and I never keep us plugged in when I'm not at the boat.

However, Jim hit on the answer.  Liquid lead acid batteries will self discharge about 2% per day.  The longer you're away, the more power goes POOF!  Eventually all those minus 2% days end up getting your batteries to ZERO.  Scary that Jim's marina guy was "surprised."  Confirms my suspicions that most marina people know didily about electrical systems and boat batteries.

Depending on how your charging system is wired, you can either buy separate small chargers for each battery bank (starting & house), or a larger solar panel for both (if you have a battery combiner in your electrical charging system).

You size the panels based on the capacity of your batteries.  Uni Solar has very good sizing information, and I'm sure with a little web searching using Google you can find their website.  Also try West Marine's website or catalog for their Advisors for solar panel sizing suggestions.

This will also help to make your batteries last longer and stay healthy by keeping them "topped off."  Pretty good investment ratio and ROI ($37 plus wiring to save $200 per battery! - don't know how many batteries you have on board.)

Also, as I've said, oh, about a dozen times before, invest in a quality three stage charger, if you haven't already.