Battery charging interval?

[Quandary]

This winter our boat is laid up in the local club boat yard which has limited electrical points and a (sensible) prohibition on permanently connecting cables to boats. In previous years, in a commercial yard with a connection for each boat, the shore power was left connected all winter and the automatic battery charger decided when to charge the batteries, but now I am connecting the shore power cable for half a day about once a month and at this interval the charger display takes about two hours to change from amber to green. The charger is a factory built in component of the Navix electrical system on the boat. The batteries are kept switched off and no draw ever happens unless the shore power cable is live; so is charging once a month enough to keep the batteries in good condition?

 

[Vara]

This winter our boat is laid up in the local club boat yard which has limited electrical points and a (sensible) prohibition on permanently connecting cables to boats. In previous years, in a commercial yard with a connection for each boat, the shore power was left connected all winter and the automatic battery charger decided when to charge the batteries, but now I am connecting the shore power cable for half a day about once a month and at this interval the charger display takes about two hours to change from amber to green. The charger is a factory built in component of the Navix electrical system on the boat. The batteries are kept switched off and no draw ever happens unless the shore power cable is live; so is charging once a month enough to keep the batteries in good condition?

Yes.

 

[VicS]

Yes but eventually as your batteries age you will find that it takes longer for them to become fully recharged.
You may be able to "power up" for more than half a day at a time or you may be able to do so more frequently than once a month but it'll be the first warning that the batteries are coming to the end of their useful lives.

Thought about solar panels to keep the batteries charged ........... Oh Argyll .... I guess not

 

[jac]

If the batteries are fully charged then might be worth looking at smallish panel just to cover the self discharge. Even in the wilds of the North you should be able to cover self discharge, especially if you are there once a month.