What causes battery crusties

[Dirtman]

In 12 years I have never had an issue with crust forming on my battery terminals on my truck. Today I checked and the positive terminal was covered in white/blue crust.

I cleaned it off with some baking soda and water, cleaned the terminals really good with a wire brush, tightened them back up and coated them in dielectric grease. I always keep my terminals clean, tight, and always use terminal grease.

So what caused this and how can I prevent it from happening again? Also checked the cables and both were visually good and had zero ohms on my meter.

Thoughts?

 

[Roert42]

as I understand this is caused by an old battery leaking, the acid causes the terminals to corrode, and you get the blue cotton candy.

 

[broncc]

Copper from the wires + sulphuric acid from the battery = copper sulfate (blue)

 

[DILLARD000]

Yep, chemistry in action!
Years ago, put in some skid mounted equipment in a chemical plant on the gulf coast;
got a call a couple of months later that the controls were not working;
turns out a nearby tank of SulphuricAcid had leaked+drained out across that concrete foundation;
ate through electrical conduits & left big blue fuzzy balls on the copper ground rods & wires.
Got a nice charge from the customer for a field call & tutorial for their electrician on how to fix the problem.
Weird & dangerous things happen in chemical plants.

 

[alwaysFlOoReD]

Got a nice charge from the customer

No pun intended?

 

[Bird76Mojo]

What causes battery crusties?

Battery Chlamydia naturally.

 

[bobbywalter]

This seems rhetorical.

 

[Dirtman]

So basically my 1 year old battery is leaking?

 

[alwaysFlOoReD]

I would call it "venting". That's what happens when batteries get mad...

 

[Dirtman]

Alternator seems to be functioning fine but I'll check it in the morning to see if maybe it's getting overcharged. Otherwise nothing abnormal has been going on with the electrical system except I've been leaving my dash cams on 24/7 but they barely draw any power.

 

[Curious Hound]

It’s just natural. The battery vents. Stuff comes out. We live in an imperfect world. Entropy happens.

 

[Ranger850]

When I switched from halogens to LEDs, this happened. I was told that of I put a piece of copper between the terminals, the copper would corrode instead of the terminals. I wedged a penny in there and that stopped it. I recently went back to halogens

 

[Dirtman]

My terminals are copper anyway.


Checked the alternator anyway, working as it should. 14.6 to 14.8 on startup 13.6 to 13.8 after a few minutes battery with truck off 12.5

 

[RonD]

Yes, it is caused by battery gases venting when battery is being charged by alternator, heated up
Usually occurs after you shut off the engine and air flow in engine bay is gone, battery is warm so there would be venting of the hydrogen gas until it cooled down, overcharging makes battery even warmer

Side post battery terminals are less prone to this, because of location but also because there is less exposed metal to react to the gases

You can coat terminals with petroleum jelly or dielectric grease to prevent the gases from contacting the bare metal of the cable ends and terminal

Those felt battery terminal "washers" do work but you have to change them yearly, they have a chemical that dissipates over time once package is opened
(people often say "these don't work" because they used some from an old or open package)

Yes, could be a sign battery is being overcharged by alternator
i.e. voltage regulator is stuck and not lowering output amps/voltage as RPMs increase
After coming home don't shut off the engine
Pop hood and test battery voltage, should be under 14volts, 13.5-13.9v is spec
With meter hooked up raise RPMs to say 2,000, alternators can only output full amps above 1,600rpms
Hold at 2,000rpms, voltage should go up but THEN drop back to under 14volts, that's the voltage regulator working
If voltage goes up with RPMs and stays up then voltage regulator is not working as it should and you will be "cooking" your battery, which means it will be venting alot more gases

 

[Dirtman]

Yes, it is caused by battery gases venting when battery is being charged by alternator

Side post battery terminals are less prone to this, because of location but also because there is less exposed metal to react to the gases

You can coat terminals with petroleum jelly or dielectric grease to prevent the gases from contacting the bare metal of the cable ends and terminal

Those felt battery terminal "washers" do work but you have to change them yearly, they have a chemical that dissipates over time once package is opened

Yes, could be a sign battery is being overcharged by alternator
i.e. voltage regulator is stuck and not lowering output amps/voltage as RPMs increase
After coming home don't shut off the engine
Pop hood and test battery voltage, should be under 14volts, 13.5-13.9v is spec
With meter hooked up raise RPMs to say 2,000, alternators can only output full amps above 1,600rpms
Hold at 2,000rpms, voltage should go up but THEN drop back to under 14volts, that's the voltage regulator working
If voltage goes up with RPMs and stays up then voltage regulator is not working as it should and you will be "cooking" your battery, which means it will be venting alot more gases

Thanks, everything seems to spec then. As I said startup voltage is about 14.6 to 14.8, then drops to about 13.6 after a few minutes at idle. Cruising on the highway at 2,500-3000rpm voltage stayed around 13.6 to 13.8 (had scanner hooked up while driving). Resting voltage with the truck off showed 12.6.

Cleaned and coated terminals with dielectric grease, tightened them up good and just threw my little 1 amp automatic battery maintainer on there for good measure. Also changed my cameras so they are not on when the truck is not. They never drained the battery (at least not enough to ever cause it not to start) because they barely use any power but again, just in case.

We will see if the problem re-occurs. I've had this issue on other old cars but like I said, in 12 years it's never happened on the ranger.