Boiling Battery

[Dino]

I had an interesting experience today. I arrived down to the boat to a very pungent smell. I thought it was something to do with the holding tank but decided to ventilate the boat well and investigate further. I discovered that one of my engine batteries was boiling with small jets of steamy gas emitting from the vents. I immediately unplugged the shorepower and switched off the isolators. Then I rang a guy who knows a lot about this stuff. He recommended that I wet a towel or blanket and place it on top of the hot battery for some protection as I remove the terminals. I got the terminals off and left the battery to cool down. My friend recommended that I let it cool rather than moving it hot. I’ll take it off the boat tomorrow.
The three battery banks are connected to a Newmar HDM-12-70 Heavy Duty Marine Automatic Carter’s Charger Converter. This is a smart charger and trickle charges.
Has anyone had a similar situation? Is it likely that my battery had a short. I had topped the battery electrolyte with Deionised water a few months ago and I checked them recently and they were fine.
The battery is a Varta Promotive Black 130ah 630a unit.

 

[Assassin]

Boiling batteries are usually caused by overcharging and usually by overvolting the battery for a prescribed current requirement so this leaves several options.

1) The battery is faulty and will not accept charge and the charger keeps providing charge.
2) The battery charger is faulty and not correctly regulating its voltage.
3) You have a poor connection somewhere and the charger reads this and provides more charge.

 

[Portofino]

Have you got a dial on your saloon console that shows charge going in in Ah ?
This is useful.
When you turn on the charger at the dock after a run out it shows what the charger is up to .
Eg
For us if we go a shortish distance from the berth say 15 mins to anchor up for the day then return this is what I see .
80 ah 24 v smart charger 2014 model for two 2x 180 ah banks , domestic and engine .

The engine batts virtually negligible charge needed , because presume float and trickle the previous night on the dock and the pair of alternators have put back any juice in the 2 x 15 mins runs that day .
How ever the domestic a different scenario............
6/8 hrs at anchor pretty drained due to 2 fridges , opened and closed often in 30 + degree outside ambient temp , a fair few bursts of the electric water pump - aft shower after swimming , various toilets , lights , anchor winch etc etc .
The domestic are fully charged when we arrive it’s the 15 mi run back the alternators with a split diode top up the engine bank first , ok not much to do .
So when I plug in the shore power then flick the main charger on I see immediately it’s pumping 60 maybe as much as 70 Ah into the domestic , it’s stuffing it in so to speak .Mean while as said engine bank is only fed a tiny amount 2/3 AH if that .
30 to 40 mins later that initial bulk has dropped to 1/2 of what it was say 20 to 15 Ah , then a couple of hours down to under 10 , then it floats down to trickle .
In the morning after say 8 hours of inactivity from a 24 v side because we are sleeping both banks now look identical say 1-2 AH presume trickle .
As the mornings activities on the boat go on with say 4 folks the charger responds and it’s output on the domestics risers to say 4/7 A h as it’s replacing what the 4 folks are taking out .

So I can see the various so called “ smart “ stuff happening in real time .
We have V meters two but tbo they both are 26/28 V and don’t seem to change .

It’s the AH meters that act as tell tales for the state discharge and charge .
I can flick switch under the same gauge to show discharge and rate of charge .

As Assassin says ^^^ you are gonna have to eliminate a faulty charger .You need to see it go through it’s smartness motions .

Whist I,am sort of happy to see 60/70 Ah being stuffed in the domestic in the first hour ( 2x180 = 360 Ah capacity) don’t want it stay that high all night say 8 hrs .I want to wake up and see 2/3 Ah - trickle happening .

 

[Momac]

Is the now deceased battery charged by the same battery charger output circuit as another battery in the same bank?
If so and if that other battery is okay it suggests the battery rather than the charger that has become faulty.

 

[rubberduck]

Get man who suggested wet blanket to come do some tests, then replace dodgy component, electrics are very sneaky.

 

[Portofino]

Is the now deceased battery charged by the same battery charger output circuit as another battery in the same bank?
If so and if that other battery is okay it suggests the battery rather than the charger that has become faulty.

It might have more than one OUT , say three like mine all work independently, eg one to domestic can stuff / bulk while say another on engines may on float / trickle or what ever .
If that’s so then because one bank output seems ok it’s not necessarily ok on the boiling bank .

 

[rafiki_]

A boiling battery can be caused by overcharging, and overdischarging. If you have a bank of batteries, you most likely need to change all in the bank. What is your voltage when charging? It should be around 13.8 for 12v batteries.

 

[Dino]

Sincere thanks for all the good advice and information. The battery had been charging fine at 13.8v. I am not sure how old the batteries are as I only bought the boat last year. My boat is a Broom Crown with Volvo Penta’s so all 12v.
The bank in question is the starter battery for the starboard engine. There are two batteries in this bank.
One slightly odd thing is that the bowthruster is fed off the other (good) battery in this bank. The bowthruster was fitted professionally by Aquatec Marine in Wargrave. Could this be causing an in balance in the bank?
Also, I did have a carbon monoxide alarm go off a few weeks ago when I was away from the boat and it was blipping when I arrived yesterday.

 

[rafiki_]

Sincere thanks for all the good advice and information. The battery had been charging fine at 13.8v. I am not sure how old the batteries are as I only bought the boat last year. My boat is a Broom Crown with Volvo Penta’s so all 12v.
The bank in question is the starter battery for the starboard engine. There are two batteries in this bank.
One slightly odd thing is that the bowthruster is fed off the other (good) battery in this bank. The bowthruster was fitted professionally by Aquatec Marine in Wargrave. Could this be causing an in balance in the bank?
Also, I did have a carbon monoxide alarm go off a few weeks ago when I was away from the boat and it was blipping when I arrived yesterday.

Without understanding the spec of your CO tester, it could have been picking up the gas discharged by the failing battery. When one of mine boils, I could smell it throughout the boat, and fortunately got to it before it went pop! I doubt that running the thruster off the one batt caused the other to boil. Looks like your charger is putting out the right voltage. It ,igniting just be old age. Change the 2 batts and put it down to running costs.

 

[Momac]

It might have more than one OUT , say three like mine all work independently, eg one to domestic can stuff / bulk while say another on engines may on float / trickle or what ever .
If that’s so then because one bank output seems ok it’s not necessarily ok on the boiling bank .

Yes the Newmar charger probably has three outputs.
So if another battery in the same bank is okay it suggests a battery fault rather than a charger fault.

 

[Deleted User YDKXO]

Yes I had a similar thing happen to me. Arrived at my boat after several weeks to find that the pasarelle wouldnt work. When I scrambled onto it via the boat next door, I found a very pronounced burning smell in the cockpit. Suspecting an electrical fault I opened the engine bay and found one of the service batteries boiling. I immediately switched off the shorepower and called the dealer who had supplied the boat. He called an electrician who came and eventually diagnosed a failed battery but no other faults. As a precaution I had all the service batteries changed

My bet is that you have experienced the same, a failed battery and nothing else. Btw this is why some marinas in the Med go around unplugging boats from shorepower after the owners leave because this in a fire risk. IMHO both you and I were fortunate to arrive at our boats before this happened

 

[dpb]

We had this two years ago, the smell was a bit like bad eggs.
Figured it was a bad battery and fitted a new one....no problems since.

 

[J12345T]

Hi,

I went through 2 sets of house batteries (over a 2 yr period) in my previous boat before I realised that the battery charger was intermittently faulty. Every now and again after plugging into shore power the charger would provide full charge current to the battery banks (I disconnect engine start batteries after engine shutdown) and boil them as you describe.

My advice is to look very closely at your charger and probably replace it.

James.

P.S. I replaced my batteries with AGM batteries as they tend not to explode under these conditions...

 

[Dino]

Thanks for the further input.
I removed the boiled/failed battery this evening and fitted a replacement battery. The replacement is a spare 140ah 800a Exide battery that my dad removed from his boat last year. He had fitted them as domestic batteries but they were not very well suited for running a 12v fridge. I charged it at home last night and when I fitted it, it started the engine much better than the old battery. I have another one of these batteries that he removed so going to swap the port engine battery next as it is labouring to turn over the engine.
My domestic bank is made up of two leisure batteries and two Trojans. The leisure batteries are sealed but the Trojans are wet. One of the Trojans was very dry and took quite a lot of deionised water this evening.
Is this a telltale sign that my battery charger is faulty and not going through the correct cycles.

 

[jrudge]

I suspect some of your issues are non matched batteries and replacement with used.

 

[Portofino]

I suspect some of your issues are non matched batteries and replacement with used.

+1 because.........
That’s really gonna confuse the “ smart charger” .
A bank should have the same type , size and ideally age .
You also have to assist the “ smart charger “ , they are not that “ smart “ and can’t tell exactly what they are connected to so need programming as which type .Wet and gel charge regimes requirements are different .

The Op,s ramping up the risk of fire mixing bats types in a bank .
Use identical bats size , age and type and check the “smart charger “ knows what they are .

 

[Dino]

Okay, the mixed batteries on the domestic bank came with the boat when I bought it last year. I will look at replacing these.
My Battery charger is a Newmar HDM 220-12-70. It is described as a Fully automatic charger/converter. I will get a marine electrical engineer to check this out. There doesn’t seem to be any option to adjust the outputs.
The charger has three independent outputs. The two engine banks will now be fine as these are good batteries with very little use.
Might be best to leave the battery charger switched off while I’m away from the boat

 

[vas]

Definitely Not mix batteries in the same bank!
Tbh, even in different banks the charge won't provide different voltage/current to the separate outputs (at least that's my experience)

V