Re: [Amel Yacht Owners] Battery Compartment Explosion

Barry Connor

Hi Jamie,
Thank's for the information. We bought AMEL 54 #17 last year,the survey indicated 2 suspect batteries. A month later we noticed that they were getting hot when being charged, sweated and we had gas and moisture in the battery compartment. Changed all 12 and start battery, now no more problems. When they were being changed everything was turned off, we touched 2 cables and shorted the batteries. No fuses, the Mastervolt 500 Inverter  
got zapped. Replaced it with a Mastervolt 2500 which just fitted, cables upgraded and fuses then put on both + and -. I like your idea of putting fuses on all the individual batteries, that's for that.

Barry and Penny Connor
AMEL 54 # 17
"Lady Penelope II"

On Jun 24, 2016, at 12:45 PM, James Wendell ms42phantom54@... [amelyachtowners] <amelyachtowners@...> wrote:


I hear from Danny that the SM has battery compartment venting at the bottom that allows air to move up through the battery compartment. That is the way to do it, as it allows make-up air to enter and go out the exhaust and therefore vent any hydrogen sulfide if it is released. While wet cells will release small amounts of H2S in operation, normally, AGM batteries do not release gas, as it is recombined internally. Vents at the bottom would also prevent any gasses from leaking into the boat itself.

The 54 does not have any ingress, only egress through the vent. It is sealed tight. That is what caused the build-up of hydrogen gas. The batteries themselves did not explode - 2 of them cracked a bit at the top, which is what caused the gas to release. The others were damaged as a result of the explosion.

I am sorry to disagree with other opinions, but air circulation is needed. Yes hydrogen sulfide is a toxic agent, but after my experience, it would be far better to let a little bit of it vent into the boat in an emergency situation, versus contain it in an enclosure that is essentially a bomb when the battery vents faster than the passive vent can exhaust it outside. In reality, it would not vent into the boat if the air intake is lower than the exhaust. H2S is lighter than air and will rise naturally.

Just for clarification, there was no essentially no charging occurring here; while no one has definitively identified the culprit, the accepted conclusion at this point is that one or two of the batteries suffered an internal short and breached on their own - likely because they were nearing the end of life at 4 years, but they came with the boat and I have no record of their service history. There was a slight solar power charge coming in, but it was early in the morning and little sun would have been illuminating the panels. There IS temperature compensation, and the solar charger is a nearly new 45-amp Morningstar MPPT controller. While it certainly could have failed, it was operating fine just before the event.

I will report more if my insurance surveyor or the electrical experts here in the yard are able to offer additional inputs.

Just as a side note, I know Amels are good boats, and I see that. They are well built. However, I have noted some less-than-stellar design decisions that likely are more the result of EU regulations rather than Amel philosophy.

I have owned the boat now for just over a year. I have only sailed/motored it for 4 days last June. Immediately after that initial delivery the engine failed. I am not going to repeat that story, but the final analysis proved that during my 4-day motor from FL to MD, saltwater had migrated into the exhaust manifold and up into the head - not because of cranking. When the water evaporated a week after arrival in MD, salt crystals remained in the engine and pitted the valves and valve seats. That seriously compromised the engine and the only good solution was a new engine. Yes, I could have rebuilt it for about half the cost - not worth it as there was a fair amount of external corrosion on the starboard aft side of the engine. The second design flaw is that there are NO fuses in any of the primary DC feeders from the batteries. That is a serious issue, as any short-to-ground or system overloads would have overheated the circuit and caused the affected wire to melt or catch on fire. Fuses are needed to protect the wires at the battery. I changed all of that and now have an array of fuses in the compartment adjacent to the batteries. And now the sealed battery compartment issue.

Perhaps I am venting now, but as others have noted, I will persevere and resolve all of these issues. I do appreciate the quality that goes into these yachts.

Thanks for the support - that is what this group is all about.
Jamie Wendell

s/v Phantom Amel 54 #044

On Friday, June 24, 2016 3:28 AM, "Jean-Pierre Germain jgermain@... [amelyachtowners]" <amelyachtowners@...> wrote:

Hello James,

Your AMEL ownership has been marred by unusual problems; mine has also not been a bed of roses but for different reasons. 

I had a NICAD battery runaway once. At High altitude, The events take a different dimension. 

Persevere, these are good boats and you will be well rewarded eventually


Jean-Pierre Germain
Eleuthera, SM007 

On 24 Jun 2016, at 08:10, Danny and Yvonne SIMMS simms@... [amelyachtowners] <amelyachtowners@...> wrote:

Hi James, how horrible. We all feel for you. You say the battery compartment is sealed apart from the vent. On our SM 299 there are five vents at floor level in the bottom of the battery compartment to allow air to enter. Does the 54 not have these vents.
SM 299 Ocean Pearl

From: "James Wendell [amelyachtowners]" <amelyachtowners@...>
To: "amelyachtowners@..." <amelyachtowners@...>
Sent: Friday, 24 June 2016 12:30 PM
Subject: [Amel Yacht Owners] Battery Compartment Explosion

I am not sure if anyone has ever experienced what just happened to me, but I think it is important info for everyone out there. My battery compartment exploded early yesterday morning. No one is certain exactly what happened, and no one who has investigated the accident has ever seen this occur. I am still up on the hard in Annapolis trying to get my new engine installation completed - that was a subject of a previous thread, and I will update everyone who followed that thread separately once I get my new engine running.

The explosion was quite severe and apparently set off my smoke detector which everyone in the yard heard. There was no fire. Oddly no one claims they heard the explosion itself, as it may have happened before the contractors started to come in for work. It blew the lid completely off of the passageway berth and into the ceiling, jamming it between the wall of the aft closet and the wall near the nav station closet. Fortunately no one was on the boat at the time, but if someone had been in the passageway between the main saloon and the aft cabin, they would have been seriously injured or even killed. I do not want to even speculate what would have happened if someone had been sleeping on the berth. I had some parts and tools sitting on the berth cushion and they were either shredded, melted, or survived depending on the material. It was a scary situation.

I am working with my insurance company and they hired a local surveyor to assess the situation. They, as I do, want to know the reason for the explosion. Beyond the damage to the compartment lid/berth and the surrounding woodwork, here are the facts:

  • At least 2 of the AGM batteries had been breached with cracks in the tops. None of the VRLA valves had popped.
  • A few of the batteries were bulged out at the sides. Not clear if that happened initially or as a result of the explosion. Ultimately about half of the 12 on the 24-volt side were "bad."
  • My shore power connections were off. The only charging source would have been wind and solar. Both of those systems have been working correctly for a long time, and early in the morning there was no wind and not much sun. We do not think it was an overcharge issue. I have multiple monitoring systems including the Xantrex that came with the boat, plus a Maretron monitor and Blue Sea meters. All were nominal when I left the boat before the explosion. Voltage was about 27.5 and there was a small load of maybe 3 or 4 amps DC, easily absorbed with the solar panels.
  • The batteries are a little over 4 years old and came with the boat. I have never had a problem with them, and the charging systems have never pushed above 28 volts.
  • The battery setup was reworked last winter by a very good contractor here in the yard. They added fuses to all the loads, and it has worked very well for months now. I find it hard to believe that there was no primary battery fusing on the boat at all, but that is still another topic for review. However, the explosion would not have been related to current flow and hence the fusing was not an issue one way or the other.
  • I have 12 Intimidator AGM batteries in the battery area with a 12V starting battery.
  • Testing them after the accident revealed about half of them to be unserviceable (either electrically or physically).

It is clear to the investigators that the explosion was the result of hydrogen gas buildup in the battery compartment. The problem they observed is that (while there is a vent at the forward part of the battery compartment, Amel seals the compartment completely). Normally the vent is OK, as any residual hydrogen will escape out the vent.. But the Amel setup prevents any makeup air from entering the compartment. Normally AGM batteries do not vent externally, as the hydrogen sulfide normally released in a flooded battery is actually recombined in an AGM setup. There are valves in a VRLA battery, which are supposed to open if the internal pressure gets too high. However, if the casing is breached, gasses will release immediately, which is what happened here. What no one knows yet is why the batteries cracked open. The bottom line is that the vent could not release the gas fast enough, and the hydrogen gas exploded as it built up in the sealed compartment.

I am going to modify the configuration by adding ventilation to the front of the battery compartment. I am also going to install 13 new Lifeline batteries (12 31-XT and 1 31T battery for starting). Good quality batteries with a modified install should prevent a recurrence. What a mess.................

All I can say is thank goodness no one was hurt.

Jamie Wendell
s/v Phantom Amel 54 #044

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