Battery Terminal Corrosion

[jasin1]

Uncovered the fifth wheel and started getting things ready for upcoming trip….found the positive battery terminals covered in thick corrosion….removed and cleaned the terminals and will check the water level but wondering why i get so much corrosion…I have a couple of boats with multiple battery’s …tractors and backhoe and quite a few vehicles and never see any corrosion like this…i do leave it plugged in all year. wondering if it could be overcharging?

 

[ChuckS]

Outgassing from the battery electrolyte.. I see it on my two GC2 wet cell batteries ..

What I have found to be most effective is after I clean and reinstall the cable terminals to the battery posts I spray them with dry silicone and wipe off any excess

I leave my RV plugged in at those all winter long to maintain the two GC2 batteries as well

 

[Notanlines]

Thanks to Google we have a veritable myriad of choices for you…..
“
The primary cause of excessive battery corrosion is overcharging; when a battery is charged beyond its capacity, it can cause the electrolyte to expand and leak onto the terminals, leading to corrosion buildup due to the chemical reaction with the battery acid.

Other contributing factors to battery corrosion include:

• High temperatures:
  Extreme heat can accelerate the chemical reactions within the battery, leading to increased corrosion.
  
  
• Electrolyte leakage:
  Damaged battery cells or improper handling can cause battery fluid to leak, resulting in corrosion on the terminals.
  
  
• Loose connections:
  Poorly secured battery terminals can cause uneven charging and contribute to corrosion.
  
  
• Battery age:
  As batteries age, their internal components can deteriorate, leading to increased corrosion.
  
  
• Faulty alternator:
  A malfunctioning alternator can overcharge the battery, causing excessive corrosion.
  
  
• Improper maintenance:
  Not regularly cleaning battery terminals and neglecting to check electrolyte levels can worsen corrosion. ”

 

[jasin1]

yeah i saw all the possible reasons but just seems odd that it only happens on my rv…my boats stay plugged in at the pier all the time and never have the issue….The battery charger/ converters on my boats are much more expensive and better quality so i guess they don’t overcharge…The one in my rv is probably overcharging while it’s maintaining.

My voltage on incommand when plugged in pretty much always shows 13.6 …12.8 unplugged

 

[JRTJH]

Are your other batteries contained in battery boxes like the RV batteries (sort of closed, but with just enough openings for moisture to enter and keep the inside of the battery boxes wet) ???

I'd make a SWAG that maybe the other batteries are open to the atmosphere so there's less "highly concentrated outgassing that saturates the air around the "dissimilar metals" at the battery terminals... Those two "dissimilar metals" act to rapidly exchange ions in a highly acidic environment" inside a closed battery box and create the ideal conditions for rapid corrosion....

While this may not be the only reason for your corrosion, I'd guess that it is a major contributor.

 

[jasin1]

Are your other batteries contained in battery boxes like the RV batteries (sort of closed, but with just enough openings for moisture to enter and keep the inside of the battery boxes wet) ???

I'd make a SWAG that maybe the other batteries are open to the atmosphere so there's less "highly concentrated outgassing that saturates the air around the "dissimilar metals" at the battery terminals... Those two "dissimilar metals" act to rapidly exchange ions in a highly acidic environment" inside a closed battery box and create the ideal conditions for rapid corrosion....

While this may not be the only reason for your corrosion, I'd guess that it is a major contributor.

one of my boats has 3 group 31 battery’s each in a box and the other boat has two 8d and one smaller gen battery each in boxes and don’t have the issue at all…i’m beginning to think it’s just overcharging…it’s showing 13.8 volts on the incommand screen while plugged in and charging right now where it usually always shows 13.6…..i did just add some water and the cells were just barely showing…it raised the voltage from 12.7 to 12.82 just adding the water while unplugged..i need to keep a better eye on the water level

what should it show as voltage on the screen for float charge?

 

[jasin1]

Outgassing from the battery electrolyte.. I see it on my two GC2 wet cell batteries ..

What I have found to be most effective is after I clean and reinstall the cable terminals to the battery posts I spray them with dry silicone and wipe off any excess

I leave my RV plugged in at those all winter long to maintain the two GC2 batteries as well

thanks..i just purchased NOCO battery cleaner and NOCO battery corrosion preventative

 

[JRTJH]

I'm attaching the WFCO "theory of operations" document that might help explain what's happening and when the converter/charger "changes modes" and what triggers each mode as well as what triggers a reversal of that change... Typically, the converter comes on in BULK MODE (14.4VDC) for a couple of hours, then changes to ABSORPTION MODE (13.6VDC) and remains there "indefinitely"... There is a "float mode" but the converter/charger will seldom advance to that mode... Why? The key to that answer is in the last sentence in the description of the FLOAT MODE: "A change in DC current will cause the converter to exit Float Mode and return to the default, or normal, Absorption Mode.

When you look at how our trailers work, any change in DC current puts the converter back in Absorption Mode. When the LP detector triggers a sample (usually every 15 seconds) it changes the DC current sensed by the converter and triggers the return to default. When the "time clock" in the stereo calls for a change, it may trigger a DC current change... On some radio clocks, there's a capacitor that powers the timer, but not the night light/LCD screen. When the timer "recharges the capacitor" it triggers a DC current change.... No doubt there are multiple more "energized circuits in the trailer"... Each of those, when they activate or deactivate will trigger a DC current change and "kick the converter out of float mode... So, you may NEVER actually read 13.2VDC on the converter output. You certainly will NEVER see "float mode" if you're in the trailer, because just turning on a light will prevent it for at least another 44 hours (that's almost 2 days) before the next time float mode could be achieved...

So, you'll almost always be in "absorption mode" (13.6VDC) even when in storage, if anything in the trailer is left energized. And, if you turn off everything, in most trailers that means disconnecting the batteries from the converter through a switch, so there's no possible way for the converter to provide "float mode"...

Here's the theory of operation...

 

[JRTJH]

thanks..i just purchased NOCO battery cleaner and NOCO battery corrosion preventative

Those little red/green felt washers and the red NOCO terminal spray is what I use on all my battery terminals in everything I own. I seldom have any "terminal corrosion" but have seen some "wire corrosion at broken insulation along the cables on my tractor and snowmobiles" usually right behind the cable end connectors where the wire is molded to the terminal end...

 

[jasin1]

Those little red/green felt washers and the red NOCO terminal spray is what I use on all my battery terminals in everything I own. I seldom have any "terminal corrosion" but have seen some "wire corrosion at broken insulation along the cables on my tractor and snowmobiles" usually right behind the cable end connectors where the wire is molded to the terminal end...

thanks for all the info John

 

[flybouy]

I use the battery terminal spray that CRC sells. I spray the terminals and and a NY exposed cable on the wire terminals. Never had any corrosion after using it.

 

[ChuckS]

I see “float mode” all the time when plugged in and the house. Nothing inside or outside turned on.. LP detector is active,