Negative Battery Terminal Corrosion?

[Bird Dog]

I went through my monthly check of fluids and miscellaneous underhood stuff yesterday and I noticed a lot of corrosion on the negative terminal battery post. I don’t drive it everyday and it has been a lot less with the “corona shutdown” but I haven’t had any starting issues or power related issues. The battery and connectors are about year old and were installed correctly (tight & clean) and the positive side was spotless. I did a thorough cleaning and got it all back to normal, but I am wondering what the possible cause would be? Too much time in the driveway due to the shutdown? Just wondering.

 

[Jerry Bransford]

Non-sealed batteries vent gasses that cause that. AGM batteries don't have that problem.

Hopefully you completely removed the connectors to clean the posts and inside of them. Not removing them to clean them can cause the connections to become intermittent and eventually cause starting problems.

 

[Goatman]

I've had good luck using those crappy felt washers on the battery terminals. After all clean and tight I also spray them with a battery corrosion stop. If you use both I've yet to have terminals corrode again.

 

[Bird Dog]

Oddly enough I used those felt washers on both terminals and put grease on them when I installed the new battery. I made sure they were good and tight. I have had no electrical issues but I was surprised to find as much corrosion as I did and only on the negative terminal. A thorough cleaning with a terminal brush got it back to normal.