Batteries isolated or not when boat not in use

[terah]

New boat is going to be sat in marina for a couple of months on shorepower.

should the batteries be left on to keep charged or isolated?

[nigel1]

Is there any need to have shore power connected. If the boat is not occupied, I would leave the shore power disconnected, just make sure batteries are fully charged beforehand.
If the shore power is disconnected, one less galvanic corrosion problem to worry about.

[terah]

Only to keep the batteries charged and maybe keep the bilge pump on (there's a seacock seized open that needs looked at when we haul out in April).

Otherwise no as batteries have been charged today.

[nigel1]

Seized open seacock sounds a bit of a worry, where is the boat (Scotland??)
If the batteries are good, they should be fine if no loads on them. I've left mine off charge for 2 months previously.

[Calif.Ted]

My boat is wired such that the on board battery charger and bilge pump are energized regardless of the position of the battery selector switch, even OFF. This is different than the way Nigel's boat has each bank switched individually, I obviously have no idea how your Seawolf is wired.

[Pete7]

The batteries will be fine for a couple of months, ours always stay on board disconnected and they are now 7 years old. A half decent sized solar panel for next winter would be good at providing a maintenance charge rather than mains. Our anodes now last 2 years with solar rather than mains charging. 30-40w would be good for a UK winter.

Hear what you say about the seacock, does the marina have a key incase quick action is needed.

Pete

[kas_1611]

Check with your marina to confirm they will allow you to remain connected to shore power when the boat is left. Many marinas will NOT allow this without prior permission and will remove power cables from boats left unattended.

If they approve it then fine but also ensure they are aware of your problematic seacock so they can keep an eye on the boat and take remedial action should it be required. They should have a key anyway but if not make sure you give them a spare.

Normally I'd say switch everything off and isolate everything. I trickle charge my house battery with a 35w solar panel tied to the coachroof but otherwise all batteries are OFF and shore power disconnected.

Too many fires start due to electrical faults

[moseriw]

affirmative: SWITCH them offline. Only a few things should be powered on:
Bilgepumps + Alarm
Daytank Pump
VHF-Transceiver
i.A. solar power charger
All duly fused of course.

[Alita49DS]

I think it really depends on what you need current for whilst the boat is unattended.

For example, over the winter ours can go for up to 5 months without a visit. During that time I run a dehumidifier which is on 240v. It can get pretty damp in Gibraltar in the winter. That means the shore power has to stay on. In somewhere like Scotland I suspect that one might also want such as a greenhouse heater.

The power having to be on it seems pointless not to leave shore power also connected so that the batteries are always topped up.

I isolate the motor battery but that seems to get charged anyway. The house batteries have to be on as the bilge pump is on 12v.

Whether it makes any difference, or is merely psychological, I have a couple of old anodes attached to a wire dunked off the stern and the wire attached to the backstay. I look forward to one of you telling me I am wasting my time - or not.

[terah]

The boat is in Italy. We have traded up from the Seawolf to a Sun Odyssey 45 (quite a jump). I'd have put more in the original post but it's snowing here too and I could hardly feel my fingers.

Have left batteries isolated and shorepower disconnected. Be useful to see charge state when we come back to see if they're OK.

The seacock is a worry. Have managed to work it free a little so it is about 20 degrees off closed. Marina have a key and will ask them to keep an eye on it.

[waterman46]

Interesting to read that your European marinas don't like or permit shore power connected while boat is not occupied. My observation is nearly all boats on US west coast always leave shore power connected. I do, and I switch all DC circuits off except bilge pumps and AC only goes to the battery charger.

I have to leave my cockpit drain thruhulls open. That is one problem with the design but pretty hard to see how to change it.

[hellosailor]

terah-
Rashly assuming you have conventional wet lead acid batteries? After 30 days the sulphite compounds that are produced by normal self-discharge become insoluble and permanent. So after 30 days of just sitting isolated, your battery will be losing capacity, permanently. Maybe not a lot, and maybe not noticeable until 90 days, but every battery maker says the same thing: You need to keep them trickle charging, or you permanently lose some capacity.

Perhaps you can find someone to go aboard twice a month and turn on the charger for a day. Better still, add a small solar maintenance charger. Either way, they require a charging system or solution that does charging properly.

[terah]

There are seven on board. The engine and generator batteries are standard lead acid. The house bank is 3 x Rolls AGM, and there are two bow thruster batteries but I didn't get a chance to check them.

Ideally we'll be adding a decent amount of solar but have not worked all that out yet. Only bought the boat today so lots to plan.

[Alita49DS]

Originally Posted by terah

The boat is in Italy. We have traded up from the Seawolf to a Sun Odyssey 45 (quite a jump). I'd have put more in the original post but it's snowing here too and I could hardly feel my fingers.

Have left batteries isolated and shorepower disconnected. Be useful to see charge state when we come back to see if they're OK.

The seacock is a worry. Have managed to work it free a little so it is about 20 degrees off closed. Marina have a key and will ask them to keep an eye on it.

Congratulations on the new boat. However, just because it is in Italy don't assume that you will not have to worry about condensation whilst you are away. Once you do, as I posted, you effectively have no choice about leaving shore power on.

As for the seacock, I would not swing on it too hard. I did with a large heads one on our Jeanneau and the handle came off in my hand. The whole cock was rotten. Now replaced with Trudesign from NZ sourced through Leesan in the UK. They are very knowledgeable and helpful. Efficient at shipping abroad.

We are moving our boat from Gib to Genoa this summer so will see what Italy is like.

[FionaJC]

Winter then solar charge and bilge pumps on automatic. In summer then Biges plus NAVTEX, Gas detection, Rasperry pi alarming out intruders and faults ples website for environemntal stull.