Battery Box Ventalation

[James S]

I've read about all I can stand on the ventilation of a large battery bank and am looking for some real world advice.

I'll have 6-6v (300amp) lifeline AGMs (total 900amp at 12v) installed in an almost square block with about a 1/2 space around them for air circulation.

My Alternator is a Balmar 210amp...regulated w/Balmer MC-612-H
I'll have temp sensors on both the alt. and the batteries.

I'll install an explosion proof fan up stream (blowing into the box) near the bottom of the box, with a ducted exhaust opening near the top to carry the heat etc. away from my fuses and other elect. connections.
Haven’t found the fan yet...low profile...any suggestions?

I know that if the batteries get hot enough the valves will open and they will gas...And the gas is toxic, explosive and corrosive.

The question is, how necessary is it that the exhaust actually vents to the exterior of the boat.

Thanks