I have this white power build up on the negative batter post. When the car was being run every day there was nothing. But it has been sitting for a little over a month and the negative terminal was almost completely covered in white powder. The battery's only 6 months old with 820 CCA.

What causes this?

White powder is caused by a seepage of the electrolyte (acid). It is a corrosion (like rust) that occurs due to contact with the metal parts. A possible cause, for heavy seepage, is overcharging the battery. Perhaps a fracture or poor seal around the terminal. The acid may have been present before the battery was stored. It may be slightly wicking up.

Will the baking soda trick work to clean off the terminal? And will the petrolium jelly prevent it from coming back?

How do I stop overcharging the battery (if that's the case?

When it comes to electrical, I'm by no means a novice, but also, I am no means an expert.

Thanks,
Casey

"Will the baking soda trick work to clean off the terminal?"

Yes, removing the acid stops the chemical reaction.

"And will the petrolium jelly prevent it from coming back?"

Good possibility. A dielectric grease on the surface will prevent contact with the acid. It still is possible that the acid is wicking up the terminal. May still end up with some white power near the case.

"How do I stop overcharging the battery (if that's the case?"

Check your charging system. Are you above about 14.7 volts? Not an expert either. The older I get, the more I haven't learned.

<BLOCKQUOTE>quote:</font><HR> The older I get, the more I haven't learned. <HR></BLOCKQUOTE>

No kidding.

Thanks, I'll give your those things a try.

[This message has been edited by Fried_Guy (edited 06-06-2002).]

You can also buy the little felt pads (green/red) that go over the terminal post below the cable and this will also prevent the corrosion effect. I have used Vaseline successfully in the past however, it gets kinda runny when it gets hot.

I gave my terminals a squirt of Fluid Film last year. No corrosion at all. It worked really well.

I also hosed parts of the car over a year ago with that stuff. It's still seeping out of the door frame to quarter seam, where I coated the inside of the quarter and door frame before installing the interior.

Peter

After cleaning the connections, try a bit of Permatex brush-on gasket sealer ( Ithink it is the "300" stuff) It works pretty well in sealing out the moisture.

Whatever you do DO NOT let any baking soda get into your battery. It will neutralize the acid in your battery and turn it into a useless box full of lead.