Battery dead, lots of corrosion.

[Allen And Brandy]

I feel stupid asking this question. But ocasionaly i go out when its real cold, and my batteries dead. theres large amounts of white gunk on the positive terminal. I know. My batteries fried, its like two years old. But what causes all that white gunk to build up on the terminal? what actually is it?

 

[RonD]

The white stuff is sulfuric acid, don't get it on your skin or clothes,

Best thing is to neutralize it with Baking soda and water while cleaning it off, make sure you rinse it off all of the metal below the battery.
Just sprinkle on the baking soda and add some water, do NOT spray water at it, sulfuric acid will get everywhere, sprinkle and rinse.
Then remove battery cables and clean those and the posts, wire brush is good, also you can buy a cheap tool for cleaning battery terminals and cables.

Batteries vent hydrogen gas, this gas reacts with the copper and lead in the battery cables/terminals and creates the sulfuric acid coating.
This can get inside the battery cables rubber coating if left uncleaned long enough, so if it looks like the copper is corroded cut back the insulation and clean it, if its bad, replace that cable.

The hydrogen gas venting increases with the charging of the battery, so when you see this type of build up your charging system might be a bit out of wack.

A battery(with clean terminals, lol) should have 12.4-12.8volts(key off).
After starting the engine battery voltage should go up to 14.2-14.8volts(battery is being re-charged from starting engine)
Then after a few minutes of idling the voltage should drop down to 13.5-13.8volts, that's the voltage regulator working as it should.
1 volt above battery voltage will maintain battery's charge, more than that will cause constant hydrogen venting.

If voltage stays above 13.9volts after a few minutes of idling then battery is being over charged, so venting hydrogen, the cause of this could be voltage regulator or wiring(voltage regulator "thinks" battery voltage is low).

If your battery voltage was below 12.4 volts(key off) then battery could be going bad, a shorted cell, this would also cause regulator to continue charging battery

 

[alwaysFlOoReD]

I just did a google search and came up with the same basics as RonD. Another mention was of galvanic corrosion when the cable side has a non-lead clamp.

Richard

 

[gw33gp]

Most of RonD's information is good except for the hydrogen gas creating sulfuric acid. Batteries do vent hydrogen gas but it is not a reactive gas. It does burn well (sometimes explodes) in the presence of oxygen though. He is right that it is sulfuric acid that causes the corrosion. There is sulfuric acid inside the battery and it most likely migrates to the terminals to cause the corrosion. There are materials you can put on the terminals to prevent or at least reduce this problem.

 

[HMFM Miller]

Put some vaseline on the terminals. It will stop the corrosion and not hurt the terminals.

 

[black_demon69]

Put some vaseline on the terminals. It will stop the corrosion and not hurt the terminals.

don't use vaseline it gets hot and melts then gets in between the clamp and the post on the battery and hinders the connection.. i would just get those red and green rings in the battery section in the autoparts store.. they are just chemically treated felt but they work.. also not as messy.. also while vaseline will work but only for a while.

 

[Tractor Dan]

I will say at times the rings didn't do much for me. I have honestly found the best solution atleast for my truck is have good terminals that are kept tight and i put a very very thin coating of dielectric grease on the posts. I also found another simple solution is just keep a wire brush in the truck and whenever you check your oil, assuming you check oil and fluids regularly just clean the terminals real quick.

 

[kimcrwbr1]

Put some vaseline on the terminals. It will stop the corrosion and not hurt the terminals.

Smear a light coat of wheel bearing grease on the clean terminals works pretty good.

 

[kimcrwbr1]

Smear a light coat of wheel bearing grease on the clean terminals works pretty good.

I should say after you get the clamps tight and it checks out good coat them with grease.

 

[black_demon69]

or just clean and spray a clear coat on terminals

 

[Mark_88]

I use silicone on mine and it keeps them free of the gunk for months...I usually have to clean and reapply every spring/fall but that is just regular maintenance...

Also use plastic guards that came off something in my truck but can't remember what they were originally meant for. This keeps the terminals dry and helps to prevent that annoying arc when I accidentally put my wrench across the terminals...

 

[feellnfroggy]

I use silicone on mine and it keeps them free of the gunk for months...I usually have to clean and reapply every spring/fall but that is just regular maintenance...

Also use plastic guards that came off something in my truck but can't remember what they were originally meant for. This keeps the terminals dry and helps to prevent that annoying arc when I accidentally put my wrench across the terminals...

silicone or a little dab of dielectric grease. basically something to protect your terminals from atmosphere.


My experience is, however if you have ALOT of build up, you need to check for a larger issue prior to cleaning and sealing the terminals, most noticable an intermittent connection issue can contribute to a faster buildup than normal, (and larger) ie a ground wire not tight, or a positive wire intermittently grounding out, such as the back of an improperly installed stereo or trailer wires, or amp system.