Battery explosion (not on ranger tug)

[stwendl]

Came across this event today and wanted to share. A sea ray 350 owner tried to start his engine when he heard a loud bang. Upon further examination he found two batteries had blown the top off.

What I could gather was that the two blown batteries were in one spot together and the third battery was separate and did not get harmed. The date code on exploded batteries were from 2011 and 2012. My guess is they may have been the house batteries. Not sure how the sea ray wire the batteries. Battery acid had spilled all over in that compartment. Guess there may have been hydrogen build up which ignited, probably poor maintenance if any.

I wanted to find out as much as possible to learn from this event, but the owner did not have much information to share, even claimed batteries were in series which made no sense in this installation.

Picture of the exploded battery in my galleryhttp://www.tugnuts.com/gallery2.php?g2_itemId=63778

 

[Navigator's Son]

...even claimed batteries were in series which made no sense in this installation.

Picture of the exploded battery in my galleryhttp://www.tugnuts.com/gallery2.php?g2_itemId=63778

Any chance they were golf batteries? I can't think of any practical reason you'd wire 2 12v batteries in series and expect your electronics to work on 24v.

Might explain why the exploded in the first place.

 

[baz]

Maybe the vent caps were plugged up. Nasty event, and a scary one. If you do learn more as to the cause let us know please.

What is JUST an explosion without fire ?

 

[edSB]

They look to be 12v, flooded lead acid batteries. If the electrolyte falls below the separators a spark can occur. A 2011 date code.. a 7 year old battery was probably near its end of life (now for sure). Keep the cells topped off.
Ed

 

[stwendl]

Yes they were both 12v. Considering the answers I got from the owner, he probably was not technically on top of this. Luckily there was no fire, just a loud boom, like a car backfire, as the marina staff told me. I was not present when this happened.

However one battery popping I believe, it both at the same time and synchronous is unlikely. There is a chance that perhaps one battery may have leaked before and already was a goner when the second popped. He reported slow start and anchor retrieval very slow.

Again, I don’t how they were wired up. If I find out more I will surely share the info.

 

[captstu]

Similar happened to me on a 450 Ah series parallel of 4 golf batteries. One. Shorted internally and others tried to charge shorted cell. LOTS of outgassing. No explosion. Luck. Agm batteries.

 

[SEA3PO]

I was working on a customers car ...cranking to start it...and the battery blew...scared heck out of me...what it was ...the water level was low and it sparked inside the battery causing it to blow up... sure scared everyone...and I ended up buying the guy a new battery....with a big smile..oops..

Joel
Kea 21' Seahorse tug
SEA3PO 22' C-Dory

 

[Romakeme IV]

Battery acid levels should never be allowed to drop below level of plates. This not only presents the opportunity for an internal short causing spark which can cause an explosion but the proportion of the batteries capacity represented by the percentage of plate area left dry is now lost.

Many off grid systems use a 24v(or higher) invertor which requires batteries to be wired in series. Doesn't sound like this here though if he was having problems with starting and windlass operation.

Many of the cheaper onboard chargers do not have accurate voltage regulation. I had one that overcharged my batteries - over 16v. It destroyed both the batteries it was charging. This can lead to excessive gassing which in an enclosed space can lead to an explosion or at best these gasses wreck havic on other electronics, wiring, etc.

Regards,

Rob