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Semi [OT]: What is the black deposit on the underside of wet lead acid battery vent caps?

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Dennis

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Jun 27, 2011, 2:42:04 AM6/27/11
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Does anyone know what the black smudgy deposit is that forms on the
underside of wet cell lead acid automotive batteries is?

It looks a little like soot and is easily wiped away.

I've heard it can suggest the battery is failing. Is there any substance to
this or is it just an anecdotal red herring?

Cheers
D.


Rheilly Phoull

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Jun 27, 2011, 3:53:29 AM6/27/11
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The technical term is "Krud" :-)
Might be worn off the casing ??

atec77

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Jun 27, 2011, 3:55:24 AM6/27/11
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Oxide
is bad

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Dennis

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Jun 27, 2011, 5:12:06 AM6/27/11
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"atec77" <ate...@hotmail.com> wrote in message
news:iu9d1e$o0o$1...@dont-email.me...


It could be lead oxide - googling had found nothing but I just looked at
lead oxides and found this:

"The so-called black lead oxide, which is a mixture of PbO and fine-powdered
metal Pb and used in the production of lead acid batteries."

http://en.wikipedia.org/wiki/Lead_oxide


We've got a few vehicles and most of them seem to have it to some degree -
even on a couple of batteries that are only 6 months old.


Dennis

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Jun 27, 2011, 5:15:13 AM6/27/11
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"Rheilly Phoull" <rhe...@bigslong.com> wrote in message
news:MqmdnVeUp46ZqpXT...@westnet.com.au...

I nearly used the common trade term of "black shit", "krud" is more
professional.

It could be from the casing but I wouldn't think so as it's to be deposited
on the bottoms of the vent plugs as if carried there by the electrolyte
"bubbles" during charging.


atec77

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Jun 27, 2011, 5:43:23 AM6/27/11
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a by product of the charging , when enough "black shite" accuumuates the
battery is buggered

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Chieftain of the Carpet Crawlers

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Jun 27, 2011, 6:58:49 AM6/27/11
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On Mon, 27 Jun 2011 15:53:29 +0800, Rheilly Phoull <rhe...@bigslong.com>
wrote:

No. It is from a failed or failing cell.

Pretty much, you are "really full of it".

Rheilly Phoull

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Jun 27, 2011, 7:09:27 AM6/27/11
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Ahhh ! THAT Krud !

Didn't come up in the original post :-)

TTman

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Jun 27, 2011, 11:29:31 AM6/27/11
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"Dennis" <den...@blibber.com> wrote in message
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Defo lead oxide...


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