battery blues (literally)

[babak]

So my car has been starting a bit slower lately so I opened up the hood to check out the battery and lo and behold this is what i found:

I cleaned it all with a wire brush and then checked the battery with a multimeter. It was reading 12.75 volts and with the car on it read 14.3 volts. When i turned on all of the accesories (lights, heater, etc) it dropped to 14.0 volts. This seems ok right?

Does anyone know what the heck that blue stuff is, why my positive clamp is made of copper (and oxidizing so much). Also ive got two wires going somewhere form my positive terminal seems kinda strange are all accords like this? (Mine is a 2008 i-ctdi)

 

[tbourner]

Apparently it's quite a common corrosion but I have to say I've never experienced it. Just take the terminal off and clean it all up with wire brushes, maybe some fresh grease when you put it back on.

 

[crolandc]

The blue stuff is copper sulphate from sulfuric acid attacking the copper wires.

 

[toffee_pie]

The blue stuff is copper sulphate from sulfuric acid attacking the copper wires.

put a blob of vaseline on them posts, or grease.

 

[edgeoftime]

Boiling water will shift most of it then a light wire brushing, smear vaseline onto post's and cable ends then refit. You obviously check under the bonnet regularly LOL

 

[Reiver]

Cosmetic vaseline is mostly ok to use but if the engine bay gets too hot, it can melt and run down between the clamp and terminal creating an electrical insulation barrier. Industrial petroluem jelly has better temperature resistance but ordinary high temperature grease works just as well. There are also proper battery terminal sprays but how many times do you disconnect your battery?

I'd suggest when starting with a clean terminal, put some grease around the terminal base only and then put clamp on, so there is direct metal contact between post and clamp, and then put grease over .