Re: [Amel Yacht Owners] Explosive episode


Bill & Judy Rouse <yahoogroups@...>
 

Jeff,

Batteries release Hydrogen gas when charging...they release a lot when overcharging. I believe the only thing that would blow the hinges off of that compartment would be Hydrogen gas. I am guessing that the release of Hydrogen gas was caused by either a short in one or more of the batteries, or a charging device overcharging. Either condition would cause the the batteries to overheat.

What was the condition of the batteries after the explosion? Were any battery cases cracked or broken? 

What was the temperature of the batteries? Were some hot?

Have you inspected the vent hose and checked that it is clear to the outside?

Batteries can be bad when delivered new. I bought 12 new house batteries about 4 years ago and 2 of them never left the dock. I tested all before placing them on the boat...2 had internal shorts.

I think maybe you were recording Amps, not Amp/hour. If you were recording Amps, it seems that 1.5 is fine, however, I am guessing that if 150-175 amps poured into fully charged batteries for 30 minutes, you could boil the batteries, releasing Hydrogen...I am not sure of this, but your alternator has an output capability of at least 150 amps. I believe it is controled by a smart regulator, but maybe not on hull #14. Is there a Smart Regulator in a plastic electrical box on the aft firewall slightly above the engine height? 

I apologize for giving you more questions than answers.

Best,

CW Bill Rouse
Admiral, Texas Navy
Commander Emeritus
Amel School www.amelschool.com
720 Winnie St
Galveston Island, TX 77550






On Wed, Jun 14, 2017 at 6:17 PM, jmkraus@... [amelyachtowners] <amelyachtowners@...> wrote:
 

I was motorsailing for an extended period trying to make as much progress to the easterd as possible.

While making omlets for myself and my crew, there was an explosion in the galley. The big plastic bowl I was mixing the omlets in blew out of my hands, and landed in the sink. It was a big loud pop, not a puff that you might expect from an excess of propane due to a burner left on. It wasn't so much an explosion as a loud POP.

My initial reaction was to think it WAS excess propane. The dials for the stove are touchy on the 54, and I thought I had made the mistake of having a burner slightly on , but unlit, and when enough propane built up, it exploded.

I checked the engine compartment, All OK.

After cleaning up the mess (it wasn't bad), and making the omlets, I went to log in the hourly numbers at the nav station, and noticed that the sea berth mattress and the battery comp artment cover were blown askew, and the facing cabinets were blown open. Upon closer inspection, the battery compartment cover had blown the hinges off.

A couple of points of note:

Batteries were replaced 10/16..replacements were the.same batteries as were originally aboard (lead acid)

New batteries were never allowed to go below 70%. Never saw below 23.3 volts

During motorsailing the AH reading recorded at that point was approx. +1.4AH  at each hourly log entry

The engine was turning 1300rpm, and it's the d3-110 (top end around 3000rpm)


I realized that there was apparent contribution of gas (H?) from the battery compartment that appears to have, if nothing else, created an independent event, and possibly, primarily caused the galley event,


I'm wondering 2 things:

1. Do es the float stage of the engine alternator produce too high of an amperage flow at float stage, during an extended period of engine usage, producing too much of a charge, causing the excess creation of the gas from the charging process?

2. Is the battery compartment improperly vented in the 54? (I thought there was a discussion of this in the past on the forum. Apologies. I don't follow the forum regularly, and may have missed this discussion

I opened the compartment regularly after the episode after the event to be safe.


If there was some kind of a protocol I wasn't following, please, by all means, let me know.

If there is something I was remiss in, or should have done differently, again, please let me know.


There was ZERO evidence of any type of a burning from the explosion.

The only evidence in the sea berth was a slight marking on the wall where the cover pushed hard into the wall on the aft end.


Any educated thoughts on the episode would be appreciated.

I will be tied up for a few months in my latest port of call as I get to the bottom of this event, along with a few other repairs, a few of which I'll seek the forum's advise.

Thanks Amelians.


Jeff Spirit Amel 54 #14









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