Re: [Amel Yacht Owners] Re: Explosive episode

James Studdart

As an aside, when our batteries blew they remained hot for many many hours (sitting on the dock). It was at least overnight until they returned close to ambient. I'd be very surprised if yours managed to cool while you cleaned up. However, it the rest of the evidence certainly points to a boiled battery.

SeaBean, SM344
Shelter Bay, Panama

On Thu, Jun 15, 2017 at 05:25 gary@... [amelyachtowners] <amelyachtowners@...> wrote:

I had two batteries 'boil off' while in the BVIs in 2015. The batteries were at least three years old and we were on shore power with float charge in progress.

While there was no explosion, the event was marked by the distinct smell of sulphur/gunpowder and by the very real heat coming through the wood of the battery compartment.
After shutting the masters off and tripping all the breakers I could think of we left the boat for four hours.
When we returned, the batteries were still boiling so I stuck a fan into the berth area to vent it and gingerly removed them and set them on the cement dock. There was quite a flood of acid/water mix in the compartment. The batteries continued to boil off while sitting on the dock for maybe 6 more hours.

I'm on a monthly schedule to top the batteries with distilled water, and they seldom take very much but exposed plates can often lead to internal shorts and a boil off. If there's a lot of gas in the battery compartment, even if properly vented, a tiny internal hot spot can ignite it and you'd hear the big 'pop'.  Thankfully, the compartment's design is good enough to contain it.

A few years prior one of the batteries in our RV 5th Wheel exploded just as we were leaving the coach. Sounded like a gunshot and then we smelled the sulphur. Pretty scary till we figured it out.  Since we were outside we didn't feel and concussion, but in the closed space below decks I imagine there was a good amount of overpressure when the battery popped.

Just glad to hear that no one was hurt!

Gary W.
s/v Adagio, SM #209
Patmos, Greece

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