Excessive battery terminal corrosion

[Kuato]

Originally Posted By: motor_oil_madman
Originally Posted By: Kuato
All good info above....add short tripping to the list of things that can cause the condition.

If the integrity of the battery case is good then gluing a penny next to the positive terminal will get the corrosion on the penny instead of anywhere else.


Does the penny have to make contact with the post?


Nope, just has to be nearby....I usually put mine about 3/4" away.

 

[Donald]

When people say over tightened can cause the problem I assume they mean the clamp not mounting bracket.

If you over tightened the clamp you might cause the post to become slightly out of round which would break the seal and cause it to leak and form corrosion? Sound like a longshot.

How about twisting a clamp too much trying to get it off, rather than using a clamp puller?

 

[JHZR2]

Originally Posted By: Donald
When people say over tightened can cause the problem I assume they mean the clamp not mounting bracket.

If you over tightened the clamp you might cause the post to become slightly out of round which would break the seal and cause it to leak and form corrosion? Sound like a longshot.

How about twisting a clamp too much trying to get it off, rather than using a clamp puller?


Ive seen one jaw of the clamp crack from overtightening.

I think there are many ways that odd forces could affect a terminal. Almost wish batteries came with 0ga potted leads, which could then bolt to an appropriate location on the vehicle...

 

[Donald]

Originally Posted By: JHZR2
Originally Posted By: Donald
When people say over tightened can cause the problem I assume they mean the clamp not mounting bracket.

If you over tightened the clamp you might cause the post to become slightly out of round which would break the seal and cause it to leak and form corrosion? Sound like a longshot.

How about twisting a clamp too much trying to get it off, rather than using a clamp puller?


Ive seen one jaw of the clamp crack from overtightening.

I think there are many ways that odd forces could affect a terminal. Almost wish batteries came with 0ga potted leads, which could then bolt to an appropriate location on the vehicle...


I can see a clamp breaking, but the comment was how could over tightened clamp damage seal between case and post.

 

[Eddie]

And another cause is the type of carrier strap that hooks to each of the posts.

 

[George7941]

Originally Posted By: JHZR2
Originally Posted By: George7941
I used to service a 1998 GM G3500 diesel van with a second frame mounted battery under the van and it always had a lot of corrosion on the positive terminal and I had to clean it every few months. The three other battery terminals on the van were fine. This corrosion persisted over the life of the van, through multiple battery replacements, from multiple battery sources - Delco, Costco etc. The experience seemed to rule out the usual causes - overcharging and cracked case around positive post


If the parallel batteries weren't perfectly matched and replaced in pairs, all sorts of funny stuff could happen.


I fail to see what funny things could happen if the batteries are not matched. The alternator was not PCM controlled and I think the only factor affecting the voltage output of the alternator was ambient temperature. I kept testing the batteries with a conductance tester and replaced a battery when it read below 500CCA. So what if one battery was at 120 mins reserve capacity and the other one was at 80 mins reserve capacity? I don't see an issue here.

 

[George7941]

Originally Posted By: Eddie
And another cause is the type of carrier strap that hooks to each of the posts.


I have one of those straps and I only use it when I am taking batteries to the scrap yard.

 

[Donald]

Originally Posted By: George7941
Originally Posted By: JHZR2
Originally Posted By: George7941
I used to service a 1998 GM G3500 diesel van with a second frame mounted battery under the van and it always had a lot of corrosion on the positive terminal and I had to clean it every few months. The three other battery terminals on the van were fine. This corrosion persisted over the life of the van, through multiple battery replacements, from multiple battery sources - Delco, Costco etc. The experience seemed to rule out the usual causes - overcharging and cracked case around positive post


If the parallel batteries weren't perfectly matched and replaced in pairs, all sorts of funny stuff could happen.


I fail to see what funny things could happen if the batteries are not matched. The alternator was not PCM controlled and I think the only factor affecting the voltage output of the alternator was ambient temperature. I kept testing the batteries with a conductance tester and replaced a battery when it read below 500CCA. So what if one battery was at 120 mins reserve capacity and the other one was at 80 mins reserve capacity? I don't see an issue here.


The batteries are in parallel. So a weak battery in parallel with a strong battery will cause problems.

 

[Colt45ws]

Originally Posted By: Donald
Originally Posted By: George7941
Originally Posted By: JHZR2
Originally Posted By: George7941
I used to service a 1998 GM G3500 diesel van with a second frame mounted battery under the van and it always had a lot of corrosion on the positive terminal and I had to clean it every few months. The three other battery terminals on the van were fine. This corrosion persisted over the life of the van, through multiple battery replacements, from multiple battery sources - Delco, Costco etc. The experience seemed to rule out the usual causes - overcharging and cracked case around positive post


If the parallel batteries weren't perfectly matched and replaced in pairs, all sorts of funny stuff could happen.


I fail to see what funny things could happen if the batteries are not matched. The alternator was not PCM controlled and I think the only factor affecting the voltage output of the alternator was ambient temperature. I kept testing the batteries with a conductance tester and replaced a battery when it read below 500CCA. So what if one battery was at 120 mins reserve capacity and the other one was at 80 mins reserve capacity? I don't see an issue here.


The batteries are in parallel. So a weak battery in parallel with a strong battery will cause problems.

Yeah, anytime you have multiple batteries connected together the best idea is always a matched set.
So you have a conductance tester, but can't see why that would affect a parallel set.
Okay, so lets say you have a new battery, measures 800CCA (so good conductance) and a old one, down to 540CCA (marginal conductance)
So when you turn the key on that V8 diesel, which one is going to be doing most of the work?
The one with good conductance, that can push the amps to turn it over. If they were both marginal, or both good, they would share. But since its easier for the new one to dump amps out, it has to do most of the work.
So now you have one battery more discharged than the other. If it doesnt get driven long enough to fully recharge both batteries, which could be hours depending on what the voltage regulator is set at; The slightly more discharged one will drain the other one until their voltage potential is equal after shutdown.
Then on the next start the same thing will happen. The fresh battery will take the hit for its lazy brother who then recharges quicker because it never put anything out in the first place.

The way they are cabled together could have an effect as well. Since they are parallel youll have the cables connecting them together, but the vehicle should connect its positive to one battery and the negative to the other battery. This way they share loading as the effective cabling length for each battery is about the same.
If the vehicle has its positive and negative both connected to one battery, with the other tagged onto that one, the battery 'closest' to the vehicle connection will be the abused battery as the other has to push its amps through the extra cabling. So then same situation as above with a 'good' battery and a 'marginal' battery. Except instead of internal conductance its the external conductance through the cabling.

 

[zzyzzx]

This thread is useless without pics:

 

[George7941]

As for the battery pics zzyzzx posted, that is the worst I have seen.

Colton, thank you for the detailed explanation but I am still not convinced. It is true that if there is a fresh 800CCA battery and a somewhat sulfated 540 CCA battery, the fresh battery will do more of the work. If the truck is not driven long enough to replenish the electrical energy expended in cranking the engine, then even if there were two fresh batteries they would both be still not fully charged. The 800 + 540 CCA battery pairing is equivalent to having one 1340 CCA battery. If 1340 CCA is adequate to handle the cranking duties I do not see any issues. The 800 CCA battery will have its life shortened a bit because it is working harder. As to which is more cost effective, the answer is by no means clear - replace both batteries together and have longer intervals between battery replacements or replace one battery at a time and have a somewhat shorter life from the fresh battery.

All this is assuming the weak battery is merely sulfated and has lost some capacity and not internally defective and drawing abnormal current from the alternator, which would be the case if it had an internal short.

 

[kb27]

I have to deal with quite a few corrosion.
Some are so bad, it covered the whole terminal and usually it's so badly corroded that it need to be changed.

To clear the corrosion salt, I use a water jet in a small pressurized container.

 

[SHOZ]

If it's corroding it's leaking. No two ways around that.

 

[SatinSilver]

Originally Posted By: motor_oil_madman
Does the penny have to make contact with the post?


I tried this and it didn't help at all. The NOCO battery treatment service at Walmart TLE did an excellent job on the two cars in the signature below.

 

[mightymousetech]

Originally Posted By: HangFire
Originally Posted By: Donald
Your battery is a leaker. The seal between the case and post was damaged.

This.
Originally Posted By: Kestas
I just checked how old my battery is... over 8 years old! I'm going on a long trip in a couple weeks. I'm glad I caught this. This explains why it recently takes just a bit longer to crank the engine before it starts. Hopefully a new battery will cure this ill.

Yes.

I've seen this multiple times. When the green fuzz grows crazy fast, the problem is a leaky battery, and a new battery is the real fix.


A leaky battery? No, just corrosion. Corrosion is an electrical based degradation, this is why you normally only see it on the positive terminal. All you need to do is put some kind of dielectric grease on the terminals or a specific battery terminal spray. We use the Wurth version here at work. I see worse than the pictures shown in this thread every day.

 

[SHOZ]

It's why they use to use lead clamps. Any acid on the cover would allow some leakage to ground if there's enough of it.

 

[kschachn]

Originally Posted By: SHOZ
It's why they use to use lead clamps. Any acid on the cover would allow some leakage to ground if there's enough of it.

Except when they don't, of course. Three out of my four cars have copper clamps.

 

[SHOZ]

Originally Posted By: kschachn
Originally Posted By: SHOZ
It's why they use to use lead clamps. Any acid on the cover would allow some leakage to ground if there's enough of it.

Except when they don't, of course. Three out of my four cars have copper clamps.
I haven't seen an OE lead clamp for decades.......

The best clamps I've seen are the cheapo ones at Walmart. Tin plated steel band type clamp. Couple bucks at the most. Work great if you have a lug on the end of your cable and not bare wire.

 

[andyd]

Grease for peace. I oil the pads I made from underlayment felt. They go on the posts After I grease the posts down to the case top.I also pack grease into any bare copper on the connections.

 

[zzyzzx]