positive battery post turing black

chas036 · Sep 22, 2019

I have a JD-B that after starting it for the last three years without problems, all of sudden the positive 12 volt battery post started turning black causing the tractor not to start until I remove the cable and polish up the post. After this, for a couple of weeks, the tractor starts good, and then all of a sudden it won't start, and I have to repeat the process and clean the posts again for it to start.

The battery is only three years old and still holds a good strong charge. What can cause this problem make the positive post turn black, and is there a way to stop it without getting a new battery?

Bob · Sep 22, 2019

Battery is probably leaking acid and/or acid vapor do to the post having torn loose from the plastic battery top.

Clean post and cable end with spray battery cleaner (or baking soda and warm water), brush them clean, install and tighten securely, then coat with spray battery terminal protector, or, if not available, give the post and terminal a then coat of heavy grease.

Hobo,NC · Sep 22, 2019

Whut Bob said..

Every battery I sale I take a brush and go around the base of the battery terminal where the lead and plastic meet with silicon dielectric compound (Tune up grease)

After I put the cable on coat it good with silicon dielectric compound... Most of the time its good for the life of the battery : )

I use to spray battery cleaner on it the bad is once the cleaner/coat absorbs acid and get saturated it make the issue worst. : (... The same applies for those worthless felt washers they sale I take them off on every battery I see them on... They become a sponge noting can be worst that keeping a acid sponge just under the connection...

John T · Sep 23, 2019

After very thoroughly cleaning that post and the cable end and insuring electrolyte levels are correct and not overfilled, first use one of the anti corrosive fiber washers, reattach n tighten the cable, then once all is done spray it with that red anti corrosive coating. If a battery is bad or overcharging it can cause excessive outgassing which can cause cable corrosion.

John T

Fordy20 · Sep 23, 2019

I have a 1966 SS396 that would do that until eventually even cleaning the battery post didn't work. Turned out to be the ignition switch. Most likely something faulty in your wiring, battery cables or starter switch.

Royse · Sep 23, 2019

I replaced three batteries in three different vehicles this year that
did the same thing. Positive post and only the positive one, turned
black as coal. None of mine had any of the normally recognized
corrosion on them, they just turned black.

One of them had been doing it for years and still worked but was
getting weak. The other two were junk right off.
The one that worked for a while was in a pickup, one was in a
tractor and the last one was a riding lawn mower battery.

DoubleO7 · Sep 23, 2019

Examine the battery terminal and the inside of the cable clamp for pitting.
Clean both with the internal/external reamer.
Not just the brush style terminal tool.
Get those pits gone and the mating surfaces back to smooth and matching tapers to insure better surface contact area.

Then when reassembled coat with the tacky red stuff mentioned.

If the mating surfaces are pitted and/or scratched/gouged bad enough, the red stuff and other types of same will only run in and help to insulate the surfaces from each other.
To some degree.

positive battery post turing black

chas036

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Bob

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Hobo,NC

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John T

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Fordy20

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Royse

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DoubleO7

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