Battery in the bilges

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warrenmarkus1

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my batteries are in the port cockpit locker and I want to move them into the engine compartment in front of the engine (free space).
One battery (engine start) will sit in the bilges, with the terminals about 50cm above the cabin sole.
The bilges are about 15cm deep, and and historically water buildup in the bilges has been lower than the cabin sole.
Does the forum have any thoughts on this?
Thanks
 
Some boats have the batteries below the cabin sole. The battery will be the last of your worries if there is 50cm of water above the sole, the boat will be on the point of sinking if it hasnt already. Perhaps you did not mean 50cm. 5cm?
 
Conventional wisdom has it that when a battery goes under water you get poisonous chlorine gas giveen off and the battery becomes useless for a mayday call. However as already said it may be far too late by then. And of course this may not aply to modern sealed batteries.

So batteries on the centre line as low as possible give more stability.
You might also consider whether the trim of the boat. Especially with lots of people down the back. You might find it desirable to get the batteries even further forward. good luck olewill
 
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Conventional wisdom has it that when a battery goes under water you get poisonous chlorine gas giveen off .................... may not aply to modern sealed batteries.


[/ QUOTE ]

Once the seawater gets in contact with the connections, whether it is sealed or not electrolysis of the salt will produce chlorine gas!

Its a popular myth that sulphuric acid and seawater produce chlorine when mixed but that is total rubbish!
 
Hi Vic
What is produced then when salt water is mixed with lead acid electrolite. I ask as some years ago I had 1200 squids worth of lead acid battery ruined when it was topped up with 'Brine water' while working in a ham curing factory. An employee had used a test sample of the brine water that they injected the hams with as the water with which to top the battery up with. This site was at the time the largest slaughter/ production plant of its kind in Europe and that little mistake emptied about 15% of the place because of the breath taking stench that was made. We had the manufacturers in to empty and replenish the cells but it was never good again, though it worked tolerably well. it always smelt. The other side of the coin was that the machines were always awash with brine water of some form and this would generaly get on to the battery tops with never a problem save for the very rapid corrosion to anything except stainless, which the operators would then do their best to destroy
 
[ QUOTE ]
What is produced then when salt water is mixed with lead acid electrolite

[/ QUOTE ] Don't misunderstand what I said. Sulphuric acid and saltwater mixed do not produce chlorine, maybe some hydrogen chloride, the gas which when dissolved in water gives hydrochloric acid, will be released but it is very soluble. It will be released as the sulphuric acid seawater mix evaporates though. Being so soluble it will dissolve in any moisture or condensation corroding anything that would be corroded by hydrochloric acid.

Getting or putting salt water into the battery is another matter. Chlorine will be produced.
 
Hi All,
Sorry finger trouble, I meant 5 cm, not 50 cm.
Thanks to one and all, you have confirmed my thoughts.
Re the trim, I don't think (hope) it will be any worse than I have currently with the batteries in the port cockpit locker. My house battery will be higher up so should I loose the engine start battery I have a plan B. The engine compartment is vented by the letterbox slot above the engine on Seamaster sailers.
Cheers
 
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