odd battery corrosion

[RonnieH]

So, about 2 weeks ago I replaced the clamp on the + on my 1929 Morris (6volt) . . There was loads of fluffy white corrosion, used a kettle of boiling water to clear it, cleaned the battery post with emery cloth . . Fitted new clamp, did 250 miles in the car last weekend, and when not in use the battery is isolated with one of those red key things, looked at it today, its fluffy again, and eating away the clamp.
Any ideas??
Ta

[Slidingpillar]

Nothing odd about it, you've got or had an acid leak.

Corrosion caused by such leaks is very persistent and washing with water is not good enough. Neutralise the spilt acid with baking soda, but quite likely the battery is going to die soon.

Google 'battery corrosion', pictures and at least one link detailing scrubbing with baking soda!

[Piersman2]

When I were but a boy we used to put petroleum jelly around the battery terminal contacts to prevent this.

No idea what used to cause it what the car makers did to stop it being a common problem anymore.

[nta16]

as above

you can use hot water to get ‘fur’ off from around the terminals but if it’s a big build up pour home baking soda made into a wet paste over the effected areas and clean with an old tooth brush, you can brush clean the whole battery top then rinse down the battery and whole of the area thoroughly with clean water to wash away the acid that the ’fur’ contained, if necessary use thick paper towels to fully dry – remove battery lead clamps and clean, secure and protect them and battery posts as detailed next

• Battery terminal posts and battery lead clamps need to be clean, secure and protected

• Clean the battery posts and battery lead clamps with something like a small brass copper brush – then put a very little dab of something like Copper Ease around the battery terminal posts (you can use a cheap artist’s brush to apply it) before attaching the lead clamps

• Protect fitted clamps and any exposed part of battery terminal posts with relevant spray, petroleum jelly or more Copper Ease (again you can use a cheap artist’s brush to apply either)

• Make sure the battery lead clamps are secure and also that the battery is held securely in position by the retaining bar(s)

• Always check the electrode level in each cell and top up each cell using distilled water – especially check before and after using a battery charger

Edited by nta16 on Monday 2nd June 16:19

[Hooli]

Piersman2 said:

When I were but a boy we used to put petroleum jelly around the battery terminal contacts to prevent this.

No idea what used to cause it what the car makers did to stop it being a common problem anymore.

I still do that with the clamps, or silicone grease on bikes (just because I've got some & smaller contacts use less up).
Isn't it one of the things that negative earth cured?

[LordLoveLength]

One cause can be the charging system set at too high a voltage. This can cause the electrolyte to boil slightly and bubble it's way out of the battery.
You don't tend to see it so often nowadays as batteries are usually sealed and alternators are better regulated.

[david.h]

In case you are scared to ask, petroleum jelly is Vaseline! Still works, but do get the terminals really clean

[Vanin]

A year ago, having taken note of these advices , I thoroughly cleaned each of the two six volt batteries on my old positive earth Jaguar.
A year later I was horrified to find more corrosion than ever, and the Vaseline was still there in liberal quantities. The white corrosion was within the Vaseline which demonstrates how ineffective it was.

It is probably due to the less regulated charging system with the dynamo, but there is no sign of acid kicking about, and the electrolyte had not boiled away at all and needed no topping up.
I think the answer must be to put plenty of bicarbonate of soda around the positive terminals of the battery as it only forms on those battery posts.
Initially I thought that the reaction needed air to make the corrosion active, hence the Vaseline, but thinking about it further with electrolysis air is probably not needed. (Any chemists out there?)
I suppose that as the terminals are made of brass which is a copper zinc mixture, then the corrosion is a mix of copper and zinc sulphate, hence the whiter appearance . If it was just copper sulphate it would be blue.

Anyone have any better ideas?

[nta16]

I read on a battery supplier's web site that on modern battery post they don't petroleum jelly (or as I prefer copper grease)

I prefer that battery posts and clamps are lightly cleaned with a brass brush or you can buy a special tool for the job

assuming you've not scrubbed through the outer layers of the battery posts and clamps to get the present crud off, and you did wash off the last lost of soda and dry the posts

wipe off all the petroleum jelly then you can use the baking soda but mix it into a wet paste and pour over the effected areas and clean with an old tooth brush, you can brush clean the whole battery top then rinse down the battery and whole of the area thoroughly with clean water to wash away any acid and the ’fur’, if necessary use thick paper towels to fully dry

the top of the battery needs to be free of dirt, fluff, muck, liquid or you can have the two posts making contact

there's thread about Rich's pos earth Aston with a funny battery crud that's also running and I think that was blue, or was it red, can't remember you'll have to look

Edited by nta16 on Saturday 31st May 23:19

[Vanin]

Thank you for that NTA, I will go on to that thread as its seems Rich ha similar problems.