Uh oh - battery booboo

[BlueStringPudding]

I was topping up the water in my batteries today when I dropped one of the screwy things that seals the top of the cells. I can't reach it but really need to run my engine as I've almost no leccy. I've made a temporary bung from a cork from a whisky bottle with a strip of industrial strength rubber glove over it to give it grip. It fits snugly. Is it going to be safe to run the engine for the next 6 hours with just that bung sealing the battery cell?

[The Boater]

That will work well enough in the long term too.

Ian.

[BlueStringPudding]

Thanks. So nothing is going to cause it to fire up into the air, then.

 

And is it still safe if there's a chance the fluid inside the cell touches the rubber or cork?

[lesanne]

If you can get to your nearest recycling centre ask if you can one off an old battery to replace it.

[Paul G2]

Battery caps are generally vented, whereas your cork stopper is not. Charging the battery can create gas and it can cause the liquid volume to increase when it gets warm. That could lead to all kinds of problems is a cell is stopped up tight.

[Loafer]

If you can bore a tiny hole through the cork it should be ok. Large sewing needle, praps, although that hole might close up again.

 

Tiny little 1mm drill bit?

[BlueStringPudding]

So one vote for safe and one for unsafe. Meanwhile I still have dim lights and a rapidly depleting phone battery.

 

Please can someone who really, really knows about boat batteries give me a definitive answer so I'm not sitting in the dark with no phone or Internet tonight please?

[cuthound]

As already suggested get a replacement, because the screw caps are vented.

 

When the battery is charged, hydrogen is evolved, which will cause a pressure build up. At best a spray of battery acid will come out when you remove the bung (painful and potentially blinding if it gets in your eyes), at worst it will explode.

[BlueStringPudding]

If you can get to your nearest recycling centre ask if you can one off an old battery to replace it.

Unfortunately not. I'm cursing myself for giving away my old batteries now.

[Loafer]

So one vote for safe and one for unsafe. Meanwhile I still have dim lights and a rapidly depleting phone battery.

 

Please can someone who really, really knows about boat batteries give me a definitive answer so I'm not sitting in the dark with no phone or Internet tonight please?

 

It will be safe with a small breather hole in it. As long as it doesn't close up when you push the cork into the 'ole.

[The Boater]

No pressure build up because it can still breathe via the screw thread.

Ian.

[BlueStringPudding]

As already suggested get a replacement, because the screw caps are vented.

 

When the battery is charged, hydrogen is evolved, which will cause a pressure build up. At best a spray of battery acid will come out when you remove the bung (painful and potentially blinding if it gets in your eyes), at worst it will explode.

Okay. Next question. What is an alternative safe temporary fix that doesn't involve travelling round the county in a taxi trying to find a scrapyard? Leaving the cell open? Sticking a gauze over it from a first aid kit? Any other suggestions?

[lesanne]

I would make every attempt to retrieve the old one, even its a lot of trouble

[BlueStringPudding]

If I take the rubber off the cork it sits very loosely in the hole as it too small for it. But it balances because of its wide top. Shall I just balance the cork go the hole like that?

I would make every attempt to retrieve the old one, even its a lot of trouble

Trouble isn't the issue. Physical inability to do so is the issue. It won't be retrieved today or probably even tomorrow and not by me at all.

Edited November 24, 2015 by BlueStringPudding

[The Boater]

I would remove the rubber in case it blocks the thread machined in the battery casing as this is what allows the cell t, any small hole you make will close wheo breathe around the cork. No need to drill the cork, any hole you make would squash shut as you compress it into the battery case.

[cuthound]

Okay. Next question. What is an alternative safe temporary fix that doesn't involve travelling round the county in a taxi trying to find a scrapyard? Leaving the cell open? Sticking a gauze over it from a first aid kit? Any other suggestions?

As a temporary bodge, you could try putting some insulating tape with a hole made in it over the hole left by the missing cap.

 

Gauze from a first aid kit is probably cotton based,xwhich will disintegrate when subjected to a spray of battery acid.

[Loafer]

Personally I'd be happy with a tight-fitting cork with a thin slot cut down the side as a breather.

Edited November 24, 2015 by Loafer

[davidb]

Hi Blue sp,

 

To be safe, Just leave it open and get your battery charged up. You are not on the road bouncing the battery along or in a rocking sea boat to slosh the acid around. To stop any splashes coming out, just put a loose fitting aerosol cap or something not metal over it till you get the old one out.

[Loafer]

Hi Blue sp,

 

To be safe, Just leave it open and get your battery charged up. You are not on the road bouncing the battery along or in a rocking sea boat to slosh the acid around. To stop any splashes coming out, just put a loose fitting aerosol cap or something not metal over it till you get the old one out.

 

That'll work too. Just don't wear posh clothes near it and preferably your specs, or goggles!

[Boat&Bikes]

I know little about batteries but apart from venting through the cap, do they not also have an overflow vent invade of over fill on the side? Ian

[Tony Brooks]

Does the battery have a hole at up high at one end and was it supplied with a length of plastic hose. If so it has a built in vent and the caps are probably sealed so no venting problems.

 

IF not then as a temporary bodge just cut a V shaped groove from one side of the cork and puncture the tip of the glove by it.

[cuthound]

Personally I'd be happy with a tight-fitting cork with a thin slot cut down the side as a breather.

Yup, that would work.

[bizzard]

If its real cork and not laquered it will be porous and allow the cell to vent, albeit gently. Corks were-are often used as vent stoppers on oil reservoirs to allow oil to drip out from the bottom by gravity. A great many steam railway engines used them as lubricator box stoppers and as stoppers for the coupling and connecting rod bearing oilers. Indeed the engines of the Princess Royal class, 'Lizzies' were nicknamed ''Corkies'' for that reason.

[Loafer]

Has anyone tried a cork subjected to acid? We wouldn't want it to disintegrate and fall into bsp's battery cell, would we?

[dmr]

just lay a bit of wood or similar over the top to stop any crap falling in, but not forming an airtight seal and it should be ok.

I have quite often taken a cap off whilst equalising and had a peep inside to see what was going on and the world did end.

I would not do this long term as I expect it will allow more acidic fumes etc to escape and cause increased corrosion in the vicinity.

 

...............Dave