Battery terminal - What is this?

[Fotoman]

This has been happening on my battery terminals (positive side only). I clean it up but it comes back after a few months. What is it and how do I prevent this from happening?

 

[RT Firefly]

Greetings,
Mr. F. After your next cleaning, liberally coat the battery post and terminal with a corrosion inhibitor. Even Vasoline will work but there ARE purpose made products.

 

[john61ct]

Terminal corrosion spray, available any Wally's for a couple bucks.

From gassing.

 

[SlowGypsy]

1. Remove terminal connection from battery post
2. Clean everything with stiff brush and baking soda/water mix (it neutralizes corrosive components of that green-blue deposit)
3. Use a wire brush or battery post cleaning tool on the post and terminal.
4. Put it back together using battery terminal grease or vaseline.
5. Make sure terminal is nice and snug - inspect regularly.

 

[john61ct]

Make VERY sure not to get anything, especially baking soda, into electrolyte

 

[SlowGypsy]

I have also noticed that this happens more often if the battery vents a lot of corrosive fumes, sometimes caused by continually over-charging, or a poorly ventilated battery box.

 

[SlowGypsy]

Make VERY sure not to get anything, especially baking soda, into electrolyte

Agreed!
Make sure all caps are secure / tape any visible vent holes, and rinse battery top and compartment with fresh water afterwards.

 

[Capt.Bill11]

1. Remove terminal connection from battery post
2. Clean everything with stiff brush and baking soda/water mix (it neutralizes corrosive components of that green-blue deposit)
3. Use a wire brush or battery post cleaning tool on the post and terminal.
4. Put it back together using battery terminal grease or vaseline.
5. Make sure terminal is nice and snug - inspect regularly.

+1^

 

[DHeckrotte]

Ditto all above. A battery in good condition in a vented place won't do this even w/o protective goos.

When you clean the terminals, using the baking soda, check the wire where it is encased in the terminal and its insulation. Swollen insulation is an indicator of corrosion within.

I haven't done this in years, neither my boats nor my recent cars seem to be susceptible. However, I used to go out to the Studebaker with a cup of warm water with baking soda in it. I'd clean off the fittings and posts, dip the fittings and wire(s) into the cup until they quit fizzing, then pour the remaining water/soda on the terminal and around the battery (taking care to keep the caps [remember when batteries had caps?] on). If I were feeling particularly tidy, I'd hose off the battery and battery box.

 

[Xsbank]

Another use for dielectric grease.

 

[john61ct]

Silicone version maybe but have to apply carefully, and it does gunk up over time.

Inhibitor spray is better

 

[FF]

A batt terminal that has been abused , hammered on may be the cause, it vents gas.

If you have solar reducing the Voltage where the charge falls back to float helps .

 

[C lectric]

Constant reappearance of that corrosion is often an indicator that the battery terminal to case seal has been damaged. Usually from banging or twisting when tightening/loosening the terminals or clamps. Use two wrenches on the nut and the terminal to prevent twisting of the terminal and a puller on the clamp type terminals for the same reason.

Clean it up thoroughly including the wire terminal , coat it with a spray, but if it still reappears shortly then one or more of the batteries has a damaged seal allowing tiny amount of acid leakage when charging.

You just have to decide if you wish to live with it or replace the batteries if the seal is the problem.

 

[Benthic2]

..... I'd hose off the battery and battery box....

wouldn't water on the top of the battery create a connection between the positive and negative terminals and be a seriously bad thing ?

 

[dhays]

wouldn't water on the top of the battery create a connection between the positive and negative terminals and be a seriously bad thing ?

Good question. I'm ashamed to say I've never thought about that over the years that I have used water to flush the tops of different batteries, mostly in cars.

 

[sdowney717]

Are these batteries gassing and bubbling a lot? Could create an acidic misting which coats the battery environment resulting in corrosion. No problem washing with water the battery, just dry it off. The acid salts will form a conductive film on a real dirty battery. Salts tend to grab moisture right from the air. Acids will turn into salts when reacting with something.

I have used lithium chassis grease without moly sometimes, mostly my batteries stay corrosion free. My float voltage is about 13.7 to 13.8 vdc.

When a battery develops a shorted cell, it will get warmer and gasses.
That is how all my batteries eventually fail.

 

[HopCar]

wouldn't water on the top of the battery create a connection between the positive and negative terminals and be a seriously bad thing ?

If it stayed wet you might discharge the battery over time. A quick wipe with a rag after cleaning should prevent that. If the top of a battery gets dirty enough, it can self discharge. Clean is good when it comes to batteries.

 

[stubones99]

wouldn't water on the top of the battery create a connection between the positive and negative terminals and be a seriously bad thing ?

Fresh water has a high impedance / resistance so any current leakage from one post to the other will be insignificant. After all, you're just washing it off, not completely dunking it.

When you put distilled water into the battery, it mixes with electrolyte and becomes conductive.

If you were washing it with salty water, that would conduct more current than fresh, and might be an issue. don't do that...

 

[Greg S]

Constant reappearance of that corrosion is often an indicator that the battery terminal to case seal has been damaged. Usually from banging or twisting when tightening/loosening the terminals or clamps. Use two wrenches on the nut and the terminal to prevent twisting of the terminal and a puller on the clamp type terminals for the same reason.

Clean it up thoroughly including the wire terminal , coat it with a spray, but if it still reappears shortly then one or more of the batteries has a damaged seal allowing tiny amount of acid leakage when charging.

You just have to decide if you wish to live with it or replace the batteries if the seal is the problem.

This answer!

Micro crack between post and case. You won't see it even if you look. The vasoline or sprays mentioned will seal it somewhat.

 

[FF]

Batt terminals are greatly helped by using copper washers and nuts to attach cables.

A big electric supply has them as they are used on high power electric.

A stainless stud , steel washer ,copper cable terminal, steel washer and perhaps SS nut sandwich would be a great way to create a battery.

 

[sdowney717]

Batt terminals are greatly helped by using copper washers and nuts to attach cables.

A big electric supply has them as they are used on high power electric.

A stainless stud , steel washer ,copper cable terminal, steel washer and perhaps SS nut sandwich would be a great way to create a battery.

SS also is a poor conductor of electricity, and a battery has to deliver a lot of current. I would not add any more SS than is already there. Resistance creates heat.

 

[jleonard]

I use those green and red felt washers available at auto supply stores.
Less mess than grease and they work for me.

 

[gaston]

MMM? Id say the battery is gassing and that is a sign not to be ignored. Maybe time to consider replacement before it dies ?

 

[stubones99]

I have seen stainless steel migrate into a battery post over time. It was like the battery post was partially stainless and no way to brush it down to shiny lead.. It was on an 8d starting battery of 120hp tractor. Someone had replaced the clamp bolt with SS and it migrated...

 

[Fotoman]

Thanks for all the answers. Looks like I need dielectric grease in the short term. However I noticed something wrong with one of the positive terminals, it looks damaged at the base in someway. Since the batteries are 8 years old I think I'll look into replacing them at some point this summer.

 

[psneeld]

wouldn't water on the top of the battery create a connection between the positive and negative terminals and be a seriously bad thing ?

No, otherwise rain in your engine compartment of your car at highway speeds would constantly short it out.

 

[mramoo]

Just my humble opinion, if the corrosion on your battery is that bad every time you check it, you ether have a serious problem with your battery, OR you are not checking your equipment often enough.

 

[FlyWright]

Thanks for all the answers. Looks like I need dielectric grease in the short term. However I noticed something wrong with one of the positive terminals, it looks damaged at the base in someway. Since the batteries are 8 years old I think I'll look into replacing them at some point this summer.

I had a car battery like that a few years ago. After cleaning it and recharging in the garage, I could see electrolyte bubbling up very slightly along the post.

Sounds like it's time for replacement. 8 years is pretty good for a marine LA battery.

 

[jsc7]

This is happening because you are overcharging the battery.

Get a better charger. Do not put charging voltage on a battery that is fully charged or you will get corrosion.

 

[Art]

Had exact same build up on a batt for gen set. When I took it out of its location, so I could get good view directly over the terminal consistently building up and placed strong charger on it, I noticed slight moisture line soon appear near the terminal. Batt had for some reason developed minuscule fracture in the top of its casing and was ever so slightly gassing right up and onto the pos terminal. I replaced battery and all was fine thereafter. BTW, it had been a pretty old battery.