Battery explosion

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nedmin

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I have 2 145aH batteries in parallel for charging at 12volt and a series parallel switch for operating a large bow thruster , at 24 volts . Just got into the lock, blipped the bow thruster , which worked ok. Immediately after there was a terrific explosion . When checked both batteries , which would be in parallel then. had blown up . Most of acid remained in plastic boxes , but some had sprayed about.
I was an electrical engineer in heavy industry and never seen anything like it. As one battery had a hole in the side, would suspect that one got an internal short and shorted other out. Got everything tested out and parallel switch ok . No damage to cables and bow thruster fuse ok.
i asked for high cranking amp batteries but found out they were leisure batteries. ( in use thruster takes 235 amps )
Fitted new high cranking batteries and everything works ok. The batteries were sealed type with a hydrogen bleeder into engine room. ( engine room has fan all time engine running.)
Bit worrying , been trying to find a reasonable hydrogen gas detector. Understand a CO 2 detector will pick up hydrogen. But needs a remote alarm. Any thoughts on the above would be appreciated. Thanks
 
How old were they ?
I tend to replace every 4 yrs regardless .But tbh they show tell tells .
Domestic = fridges turn off early @ anchor * The time gets shorter as they loose capacity to hold charge .
Engines = slower turn over speed and monetary longer fire up as they degrade .Also occasionally having to use the cross over switch = they are past usefulness.

This stuff is not binary .Ie one day good and next bad it happens slowly .

Its just a case of gut feeling or sticking to a time regime to chuck out existing .


* Having said this I tend to run the geny after 4 hrs @ anchor anyhow .
Two reasons .
1- to top up domestic as the fridges x 2=in the med heat are working hard. It pumps in 40 Ah into a 360ah bank and tops up in 30 mins anyhow .There’s a school of thought never let em drop more than 50 % .I have seen 80 Ah on the dials being stuffed in mind you .
2 - simply to give the geny a run out - you know use the thing + the so called “ smart” charger
 
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Opens up the shore power ( + “ smart “ charger ) on all the time in the marina - or close it all down turn it off when you leave the boat for fear of electrolysis / galvanic corrosion debate .

By “ smart “ charger one that morphs into a trickle charger / batt maintenance de sulphur gizmo after it charged em up .

You are damned if you do and damned if you don’t.
Turn the lot off and walk away for the winter and the batts decay prematurely ……sat there sulphating slowly dropping charge .Next season you find out , one way by means of this thread Kaboom !

Or leave the shore power on + it’s charger run the gauntlet of leaky earth ( or such like ) from your own boat or a neighbours mankly maintained boat and your zincs disappearing before Easter .
But you batts lasting and behaving normally.

Choose your poison .

I personally over 16 yrs and various spurious neighbours have opted for the latter .Mind you quality Zincs and planty of of them kg wise .

I do not follow the 12/12 rule .Got dive gear and change when they look worn rather than wait for the annual lift .

Each to there own on that .

Never had a batt fail fully or blow up and the shore power + chargers are always on .
 
nedmin said:
i asked for high cranking amp batteries but found out they were leisure batteries. ( in use thruster takes 235 amps )
............................................................................ Any thoughts on the above would be appreciated. Thanks
Click to expand...

Bingo!
 
penfold said:
It's only bingo if the current draw was greater than the batteries can put out.
Click to expand...

Show me a leisure battery pair in parallel (other than LiPO) that can output 235 Amps and I'm guessing a start load much higher. The plates will warp. short and BINGO!
 
BruceK said:
Show me a leisure battery pair in parallel (other than LiPO) that can output 235 Amps and I'm guessing a start load much higher. The plates will warp. short and BINGO!
Click to expand...

Back in the 1990's, may be later also, Sealine fitted leisure batteries to both emgines as start batteries, never a problem.

Could be a faulty battery, could be a charge problem, find a fault, do not assume a fault to fit.

Brian
 
My battery box has a fan, switched on automatically whilst charging. That should mitigate most risk I would have thought.
 
Leisure batteries have few but thicker plates. Thicker gives them more stability against warping and damage but lessens the current you can draw from it. A really good leisure battery such as a Trojan may only have a recommended max draw of 75A@6V. From there there are many divisions up to what would be considered a starter battery. So saying a leisure battery can be used as a starter battery is a bit misleading. And honestly the same can be said of the OP's term of leisure battery or the manufacturer thereof. Even so I would be very wary of using a leisure battery on a bow thruster. It may have a current draw rated at 235 Amps but a starting draw several factors higher, which is why I wasnt surprised when he said
nedmin said:
blipped the bow thruster , which worked ok. Immediately after there was a terrific explosion
Click to expand...
 
Portofino said:
How old were they ?
I tend to replace every 4 yrs regardless .But tbh they show tell tells .
Domestic = fridges turn off early @ anchor * The time gets shorter as they loose capacity to hold charge .
Engines = slower turn over speed and monetary longer fire up as they degrade .Also occasionally having to use the cross over switch = they are past usefulness.

This stuff is not binary .Ie one day good and next bad it happens slowly .

Its just a case of gut feeling or sticking to a time regime to chuck out existing .


* Having said this I tend to run the geny after 4 hrs @ anchor anyhow .
Two reasons .
1- to top up domestic as the fridges x 2=in the med heat are working hard. It pumps in 40 Ah into a 360ah bank and tops up in 30 mins anyhow .There’s a school of thought never let em drop more than 50 % .I have seen 80 Ah on the dials being stuffed in mind you .
2 - simply to give the geny a run out - you know use the thing + the so called “ smart” charger
Click to expand...
The batteries were 3 1/2 years old. No heat apparent on cases
 
Leisure batteries are for leisure type drains and certainly not designed for starting engines and this is your issue.

They are designed to have lower, but continual discharges and not a sudden surge from a starter moptor
 
Assassin said:
Leisure batteries are for leisure type drains and certainly not designed for starting engines and this is your issue.

They are designed to have lower, but continual discharges and not a sudden surge from a starter moptor
Click to expand...

For some years there have been so called leisure batteries available which also have a very good CCA rating. Also known as dual purpose batteries .
I have this type of battery as a dedicated starter battery. On my boat the domestic bank also starts the starboard engine.
No doubt there are some deep cycle batteries available that have no CCA rating so would be unsuited to engine starting .
 
Well, yes. How much lead there is in a battery determines this. I dont think there is a standard that says X kg of lead to Y volume draws a line between the two. But the makeup of high CCA is generally thinner and more plates per cell but less lead overall and deep cycle being thicker, fewer and more lead overall. The amount of energy stored is related to how much lead is in the system and thicker, fewer, plates. But as above fewer plates deliver less CCA, yet hold more energy and are more resistant to the abuse of deep cycling. Within that little lot there can be so many permutations that borders blur. Even so, a battery designated as Leisure battery is always going to have a strong bias as opposed to dual and starter with dual having a bias towards CCA but being more resilient in providing the CCA without voltage dropoff under various discharge states.
 
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