battery compartment-to vent or not?

[digby sailor]

I have a 78 hunter30 Im repowering anybody familiar with these boats knows that they have in my opinion a lousy engine compartment with respect to being compartmentalized and sound proofed.Ive removed my old tired yanmar and the battery boxes,fuel tank,and the shelf the fueltank/batteries rest on.When i reinstall the shelf and the tank and batteries I want to install a bulkhead to separate the engine compartment from the aft area under the cockpit sole which invariably transmits sound from the the engine through the lazerette acting as a big resonance chamber.I have 2 dorades on the stern which I would turn one forward and pipe them to this bulkhead I install as a way of providing adequate ventilation just wondering if there is any reason why I shouldnt do this.The ventilation should be adequate my biggest question is rather or not the batteries should be in an area with little ventilation?I have heard of boats having them installed under salon seating so I doubt this would be a concern,however,any ideas or suggestions welcomed

 

[Bill1565]

Batteries are a lot like people. They like moderate temperatures, some ventilation. It would be good for the batteries if they were shielded from the heat of the engine room. It would not be good to store them in an air tight chamber. They do give off gasses when being charged, and the gasses should be allowed to escape, not be trapped in a sealed coffin.

 

[Johnb]

They absolutely must be vented, even if they are of the sealed type. Charging batteries give off hydrogen and oxygen. Hydrogen is actually quite difficult to trap due to its light weight and small molecular size but requires very little energy in the way of a spark (could be from static) to set it off. I have seen steel boxes bent and batteries shattered (with a horrible mess resulting) from explosions caused by a loose fuse within an enclosed battery container.

I would also suggest that batteries should always be in a battery box that will prevent shorts and contain them safely.