Re: Battery Compartment Explosion


Ralph Caruso
 

I used to work in a field where water was disassociated into hydrogen and oxygen, and I can tell you that any accumulation of this mixture (called  a "stoichiometric mixture) can explode at the very slightest application of energy.  We had several experiences where this mix accumulated inside steel pipes, with no ignition source available whatsoever, and detonations occurred.  The ONLY way to avoid a detonation is to vent the space, either by forced ventilation or with natural ventilation pathways  that continuously slope upward, with NO voids that could accumulate the gas. I remember that the amount of energy that was required to cause a detonation was described as "the amount of energy that a mosquito uses to do a pushup" - somewhere around 0.5 erg, if I remember correctly - so all sorts of things can set it off.

I am not an Amel owner - I lurk here for good ideas that I can use on my Jeanneau - but I have 4 golf cart batteries, one engine starting battery, and one genset starting battery under the berth in my aft stateroom, and I have installed those catalytic combiner battery caps on the golf cart batteries, while the starting batteries are "sealed" lead acid.  I also have a small fan that exhausts the battery compartment into the boat whenever it senses voltage on the batteries above 13v - ie, charging is occurring.  I would prefer to vent overboard, but can't figure out a good piping solution that would also keep the water out while ensuring that it NEVER slopes downward.  I figure that the risk of water coming into the boat from a bad vent design would be higher than the risk of a hydrogen accumulation inside the boat - it is not very airtight, with the main hatch almost directly above  the batteries.

Interesting to hear about hydrogen explosions in boats...

Ralph Caruso
s/v Petillant
Jeanneau SO43DS

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