Where best to site the batteries?

J

jollysailor17

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At present the boat has her 3 deep cycle marine, wet, batteries below the starboard quarter berth, which is all well and good. Thinking about knock downs and water sloshing around down below, I am thinking of creating a reinforced battery box in the bottom of the starboard quarter locker, abaft the transom, with a hydrogen vent. This is right below the wind generator mount, which is handy, but some rewiring will be necessary. Before starting on this work, I thought I would ask the panel for their thoughts on this idea and if other people have re sited their batteries or just left them where they are?
 
It always helps when answering a question like this to know what sort of boat we are talking about. But your profile gives little information unfortunately.

If it is a light displacement boat it is always good to keep the wieght as close to the centreline in both axis as the boat will ride better as a result, so I would be reluctant to move the batteries towards the stern. But if it is a heavy displacement boat it is unlikely to make the slightest bit of difference.

I notice you are concerned about water sloshing about. I have a flat bottomed boat that with a pint or two of water in what pretends to be a bilge will slosh a considerable distance from one side to another. My battery terminals as a result suffer from green verdigris, but everything works and no harm is done. I had a knockdown below the horizontal in 2007 and ended us with a cabin with 2 or 3 feet of water sloshing above the sole. Until I was able to get rid of the water for most of the time my two batteries were covered. It was interesting to note that the instruments that were working off the batteries covered in salt water continued to work quite well and I was even able to start my electric bilge pump [although it wasn't much use with the quantity of water involved] which runs off my engine battery. Four years later I am still using those same batteries. I did buy a spare in the US last year as I thought my domestic battery wasn't putting out the ampage it should but I never fittted it as the domestic battery managed to make the return journey without failing.
 
I'd leave them under the quarter berth, it's where mine are going, my quarter berth is sealed off from the bilge, so I have water sloshing in there it mean's it's higher than the bunk tops!
 
Hi Glayva and Ceirwan
Thanks for that. I am new to the forum, but have now added a bit more detail about myself. I have a new boat. old but new to me, which is a west country heavily built sloop. My cruising ground is the Celtic Sea and this year I am planning a cruise to Norway.
When your batteries were swamped didn't you get a chlorine gas reaction between the lead acid and the sea water? Interesting that they are still going strong four years later.
 
jollysailor17 said:
Hi Glayva and Ceirwan
When your batteries were swamped didn't you get a chlorine gas reaction between the lead acid and the sea water? Interesting that they are still going strong four years later.
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The 2 batteries which are the cheapest I could buy on Ebay are both sealed, so there was no escaping acid. What did surprise me was that they continued to make things work. I would have thought the seawater across both terminals would have shorted out resulting in a massive discharge - but not so. And yes it is surprising that Ebay's cheapest are still going after 4 years [7 years if you count the total time they have been installed] and being completely covered in sea water. I also occasionally use my leisure battery[105 amps deep cycle] to start my engine in cold weather when the engine takes a lot of cranking with no pre-heaters and my 55 amp [cranking] starter battery has run out of charge. Maybe really cheap batteries are designed to put up with more abuse than the dearer ones are :-). The only thing I do ensure is that they remain connected to a solar panel [one for each battery to keep it simple] at all times so that they are constantly topped up in sunlight; and I think this helps them a lot.
 
jollysailor17 said:
Hi Glayva and Ceirwan
Thanks for that. I am new to the forum, but have now added a bit more detail about myself.
Click to expand...

What is 27 feet long and weighs 5 tonnes? At least that is what your profile says your boat is.

My boat is 27 feet long and weighs 3 tonnes before I load it up with water, food, spare sails, spare rigging, tools, additional screws, nuts and bolts, general junk and books - say 8 tonnes.
 
mine is smaller

Glayva said:
What is 27 feet long and weighs 5 tonnes? At least that is what your profile says your boat is.

My boat is 27 feet long and weighs 3 tonnes before I load it up with water, food, spare sails, spare rigging, tools, additional screws, nuts and bolts, general junk and books - say 8 tonnes.
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What is 27 feet and weights 3 tonnes !
The Figaro is 30 feet long and weights 2,75 tonnes. With an extra of about 1 tonnes of equipments and crew in JC configuration.
Eric
 
Whatever the length and/or weight of your boat, I would aim to keep the batteries as central as possible, with the shortest possible cable runs to the alternator and instrument panel in that order of preference.

I would think sea water across the terminals of a battery would only cause a leak of amps rather than a catastrophic discharge, as would be evidenced by John's experience.

Guy
 
Bonjour
Now, more in the subject. The best place for the batteries is just above the keel as near as possible to the engine. There are some water proof (but not closed) special bocks to prevent water invasion and to secure the batteries in case of knock-down.
Eric
 
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