How do you leave the batteries?

[Dr. D]

We recently bought a 2001 Jeanneau Sun Odyssey 37. We are pleased!

I was going to do as I did with my other boats, leave the shore power on and the batteries connected to the charger. However, the boat manual says the batteries should be disconnected when the boat is unattended. Which do you do?

[Sailmonkey]

Stop reading the manual, leave the batteries on and keep the beer cold.


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[a64pilot]

OK short time as in like gone for a week or two, shore power connected and batteries on float.
Long term as in gone a couple of months, disconnected, assuming boat on the hard, but if in the water and the batteries are disconnected, whats going to power the bilge pump?
Now if I lived up North and boat on the hard for Winter, batteries are coming home with me and kept from freezing and probably on float.


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[Mike OReilly]

A64 is right, and SM is wise. Agree with both. Just make sure you have a quality 3-step charger and she'll be fine.

In fact, I've left batteries on shorepower charger all winter on the hard (in hard freeze latitude), fully connected, and they were great. Of course, I've also killed batteries doing this when the charger got disconnected, so A64's advice is probably better ;-)


Why go fast, when you can go slow

[model 10]

I just turn everything off for 5 months. However there might be a very slight drain through the batt switches. Bilge pump is direct so it would stop after 7 batts died but our boat is dry so not really a concern.

[barnakiel]

A small solar panel may solve this.

When we leave our boat, I disconnect from the shore BUT then again we do not have fridges/freezers, etc.

It is very odd what the manual says. I have never seen this before.

Could be an interesting adventure to ask the manager what the point.

b.

[Dave Lochner]

Originally Posted by a64pilot

OK short time as in like gone for a week or two, shore power connected and batteries on float.
Long term as in gone a couple of months, disconnected, assuming boat on the hard, but if in the water and the batteries are disconnected, whats going to power the bilge pump?
Now if I lived up North and boat on the hard for Winter, batteries are coming home with me and kept from freezing and probably on float.


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If you have a good 3 stage charger, leave it plugged in when you're at the dock. Batteries prefer to be fully charged.

In the fall, make sure the batteries have enough water and are fully charged. Disconnect the negative terminal. Go home and have warm toddies.

The self-discharge rate for a battery is related to temperature, the colder the temperature the slower the discharge rate. A battery in a warm basement will discharge faster than a battery in a cold/freezing boat.

If the battery is not fully charged or is getting old and the specific gravity of the electrolyte is getting close to pure water, then the battery may freeze, but, if they are in that condition it is time to replace them anyway.

The last set of batteries I had only lasted 8 years using this method.

So, in the winter, save your back and leave them in the boat fully charged.

[Paul Cyre]

My boat is on the hard, been that way now for two years. Batteries were removed. I was told by an old salt that there are more boats that sink on land than in the water. Without the batteries how will the bilge work should water begin to enter the boat. My solution was to install a drain in the bottom of the bilge, works great. We did not take on water but horror of horrors my diesel fuel tank ruptured and all the diesel went to the bilge. Without that hole in there the boat would have been in a real mess. Live dangerously, put that hole in if there is no power.

[Island Time O25]

I can't imagine any boat in 2016 without some kind of decent sized solar panel or two or more. So it's not that hard to keep the batteries topped up during short or long absences.

Wouldn't trust shore power during any long absences. Too many horror stories about cords and plugs malfunctioning, not to mention stray currents, over/under currents, etc.

[a64pilot]

Hadn't thought about it before, but on mine pulling the depth / speed transducers would give me two large bilge drains

[nigel1]

Solar panel would be the way to go.
I disconnect shore power when the boat is unattended, biggest concern being stray currents and galvanic corrosion, despite having a galvanic isolator fitted.

[boeing1]

key word here is good charger. i have seen too many boats where the batteries have been cooked

[sailorchic34]

I try to leave my batteries happy and satisfied, without all that drama.

I also leave them with solar connected and battery charger off.

[leftbrainstuff]

Batteries like to be charged. Why does the oem recommend not leaving the charger on? Not what i would consider best practice.

A small solar panel or regulated solar is a good compromise. No shore power issues to worry about.

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[a64pilot]

Originally Posted by leftbrainstuff

Batteries like to be charged. Why does the oem recommend not leaving the charger on? Not what i would consider best practice.

A small solar panel or regulated solar is a good compromise. No shore power issues to worry about.

Sent from my SM-N900T using Cruisers Sailing Forum mobile app

Gotta think it came from their legal dept.