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269sky

Repairing the damage and clean up after exploding batteries

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Hi there

 

We managed to get down to the marina yesterday to survey the damage of the exploding battery - it had done a good job. Our lovely grey primed engine room was splattered with acid and the primer had lifted in some places and was bubbled in others. We spent most of the day scraping and cleaning up as much of the acid as we could by using a very thick mix of bicarbonate of soda with water and then wiping down with kitchen roll. I have struggled to find any information on how to deal with this so would appreciate any help please.

 

Was the method we used correct - I read some just chuck the soda down onto the acid damage but it happened about a month ago? Do I need to do anything else or is there a product I can use to neutralise it by spraying everywhere in the engine room that won't damage the wiring etc. as I am sure there must be areas we didn't reach?

 

Do I need to scrape all of the bubbles off - it is impossible to get at them all in a trad stern?

 

The acid spilled on some copper piping - I washed it down but will the acid damage it?

 

I now need to repaint the area prior to fitting the new batteries so it is best to treat the rust with something such as Fertan and then use a zinc phosphate primer?

 

Suggestions much appreciated

 

 

 

 

 

 

 

Should I use

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...

 

The acid spilled on some copper piping - I washed it down but will the acid damage it?

 

...

Yes, it's just a question of how much of this went on:

Cu + 2H2SO4 -> CuSO4 + 2H2O + SO2

or in layman's terms Metal+Acid=Fizz+Damage. Most metals will react with most acids.

The more acid there was on it, the more of your copper is gone, but if you're lucky, most of it may have run off and you won't have lost enough metal to make your pipes leak.

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You are doing the right thing.. Sodium bicarbonate to neutralise the acid. Put this everywhere. You can just chuck it in the bin after.. It makes sodium sulfate and carbon dioxide. Sodium sulfate is benign, and indeed is a constituent of Epsom salts people put in their bath.. Treat All metal, including copper.

 

Then wash down with water, and dry off. IF it's easy (I,e accessible) I'd be tempted to remove all the paint you can, treat with owatroll or similar (on e steel, not copper), and repaint with appropriate paint. Some paints are acid resistant, others not. Best be safe.

 

Bad luck.. Must be a nightmare to clean up.

Edited by FidoDido

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If it happened a month ago then I would have thought that no active acid will still be remaining, i.e. what was spilt will have reacted with the steel/copper until no acid remained (see Peter's chem formula), so I'm not sure you need to worry about neautralising stuff now.

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Yes, it's just a question of how much of this went on:

Cu + 2H2SO4 -> CuSO4 + 2H2O + SO2

or in layman's terms Metal+Acid=Fizz+Damage. Most metals will react with most acids.

The more acid there was on it, the more of your copper is gone, but if you're lucky, most of it may have run off and you won't have lost enough metal to make your pipes leak.

I believe the reaction is

Cu + H2SO4 → CuSO4 + H2

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Thanks so far for the suggestions most helpful. I have a can of Owatrol so that seems like a great idea - should I use it neat on the to the dry surface first and then use the zinc phosphate primer after (maybe adding some into this as well?)

 

Hmm absolute nightmare - did consider swapping the boat for another one ....if only lol. Love the trad stern for the extra room etc but you really need to be Houdini to get in the back :o( .

 

I just want to get it all re-painted before putting the new batteries in.


BTW I poured the soda mix over the copper and it did seem to wash off....the acid just went everywhere!!

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Not An Expert Warning. I would think the copper should be ok, after all solder flux is an acid? What made the battery go bang? any ideas?

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Clean clean and clean again . Don't even think of painting till you have had a really good clean up and removed all the damaged paint.

 

I'm sorry you've had this to deal with. It's a messy horror . Do you know what caused the exploding battery. Quite a few boaters seem to have this problem

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The the most likely reason for exploding batteries is the hydrogen, evolved when charging, being ignited.

 

This is often caused by an internal short, but can be caused by overcharging and insufficient ventilation.

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The the most likely reason for exploding batteries is the hydrogen, evolved when charging, being ignited.

 

This is often caused by an internal short, but can be caused by overcharging and insufficient ventilation.

Oxygen is evolved too, and the hydrogen + oxygen mixture is in the correct proportion for an explosion.

 

As Cuthound says, an internal short can create a spark, as can a fracture where the cells are interconnected. Low electolyte level makes an explosion more likely.

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I fitted a new sealed stater battery a couple of months ago. The other day I went to check the electrolyte levels in the domestic batteries only to notice a sticker on the top of the new starter battery. Basically it was a danger warning to make sure you remove a little red bung in the air vent (used to prevent spillage during transit). I pulled it out using some plyers to hear a massive relef of pressure!!

 

Moral of the story, read things properly before doing a job!

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I fitted a new sealed stater battery a couple of months ago. The other day I went to check the electrolyte levels in the domestic batteries only to notice a sticker on the top of the new starter battery. Basically it was a danger warning to make sure you remove a little red bung in the air vent (used to prevent spillage during transit). I pulled it out using some plyers to hear a massive relef of pressure!!

 

Moral of the story, read things properly before doing a job!

Ordinary lead acid batteries should never be sealed in this way, even for transport, because of the risk of pressure build-up. 'Sealed' lead acid batteries have pressure relief valves for safety.

 

Many batteries are provided with an L-shaped plastic adapter and drain tube. These can be linked and vented outside the boat. Obviously any vent hole at the other end of the battery would need to be plugged.

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I've come across "plugged" batteries on several occasions, however they were used to supp!y fire alarm panels. Some were lead acid and some were ni-cads.

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I've come across "plugged" batteries on several occasions, however they were used to supp!y fire alarm panels. Some were lead acid and some were ni-cads.

Hopefully they have internal pressure relief valves. Sometimes they are described as valve-regulated.

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Oxygen is evolved too, and the hydrogen + oxygen mixture is in the correct proportion for an explosion.

 

There's a fair bit of oxygen in the atmosphere just dying to get it together with a couple of hydrogen atoms.

Edited by Machpoint005

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We only replaced one battery rather than the whole bank (the other two were probably on their last legs) which may have contributed to the battery exploding or as someone mentioned in my other post a possible wiring problem causing a spark? We are going to replace the whole lot this time and get someone to check over the electrics/wiring at the same time.

 

So bringing the conversation back to my original post :o) - should I use Owatrol then the zinc primer? We really did wash it down yesterday with the bicarb/water mix (1:3 bicarb) ...should I do it again or will this suffice? The battery explosion did happen about a month ago and although someone did kindly mop up most of the acid it was only yesterday we were able to clean it down properly. As someone mentioned earlier would the acid have lost it's strength by now or is there anything else I should do prior to painting the Owatrol on?

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The electrolytic action breaks down the water in the battery to produce Hydrogen and Oxygen in a ratio of 2 to 1 as in H2O, so free oxygen on the atmosphere is not required for a "Bang"

Phil

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There's a fair bit of oxygen in the atmosphere just dying to get it together with a couple of hydrogen atoms.

An explosion with hydrogen and oxygen is much more spectacular than one with hydrogen and air. If that occurs in a container with little ventilation, such as a battery, the results can be nasty. Modern calcium batteries gas less and presumably are safer, but any lead acid battery will gas if overcharged.

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Hopefully they have internal pressure relief valves. Sometimes they are described as valve-regulated.

I am not talking about valve regulated sealed lead acid batteries. As you correctly say these have an internal valve, but are completely different animals.

 

The batteries that I have seen with transport plugs left in were lead acid and nicad batteries used to supply fire alarm panels. The batteries have small plugs in them to stop the electrolyte from escaping during transportstion. The installation contractor should remove these before use, but sometimes forget. When the plug is left in and the battery charged, it swells up due to the pressure of evolved gas. They either explode, or as the OP found out, release a jet of acid and gas when the plug is removed.

 

Most leisure batteries are dispatched to the supplier dry and the supplier adds the electrolyte, but this isn't always the case. If wet batteries have to be dispatched, they often include transit plugs to prevent spillage of electrolyte.

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So bringing the conversation back to my original post ohmy.png) - should I use Owatrol then the zinc primer? We really did wash it down yesterday with the bicarb/water mix (1:3 bicarb) ...should I do it again or will this suffice? The battery explosion did happen about a month ago and although someone did kindly mop up most of the acid it was only yesterday we were able to clean it down properly. As someone mentioned earlier would the acid have lost it's strength by now or is there anything else I should do prior to painting the Owatrol on?

Obviously it's hard to tell without seeing it but it seems to me you've given it a good clean up.

I'd just give the paintwork a rub down with scotchbrite to provide a key (especially where you've had some blistering) then use the zinc primer.

Edited by pippawatson

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Agree, zinc phosphate primer only inhibits corrosion as such if applied directly to suitably prepped metal (eg wire brushed or better)

 

cheers, Pete.

~smpt~

Edited by smileypete

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Just to clarify just the Zinc primer not the Owatrol as well (there is a bit of rust where the metal has got wet from the acid and cleaning down).

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If the rust can be removed reasonably well, use just Zinc Phosphate primer then a good bilge paint .

 

If the rust can't be removed eg lack of tools, access, time; then enough coats of Owatrol to fully seal it, then bilge paint on top.

 

There are other ways but if Owatrol is to hand then might as well use that. smile.png

 

cheers, Pete.

~smpt~

Edited by smileypete

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Would it be worthwhile to erect some ply partitions outside the battery box to contain the acid in case of a potential battery explosion and prevent the acid spraying over the rest of the engine space? Since you can't seal up the battery box as it needs to vent (and this would simply increase the explosive power), it just struck me as a possibility?

Edited by blackrose

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