Both. All battery terminal corrosion is from a leaking battery terminal or acid somehow making its way onto that connection, it is NOT caused by the electricity or anything like that, it is 100% of the time acid touching the metal and causing a reaction.
It is very hard, pretty much impossible to bond lead to plastic, most batteries are manufactured with an o ring embedded in the plastic to seal against the lead terminal. This often doesn’t help, acid wicks up and out.
Best thing to do is start off with disconnecting and cleaning the corrosion off of the terminals, install those felt anti corrosion disks, they soak up and neutralize the acid under the terminal where it’s coming from before it wicks up into the connection, protecting it, then spray it all down with battery terminal protectant, you’ll never have a corrosion problem after this.
Both. All battery terminal corrosion is from a leaking battery terminal or acid somehow making its way onto that connection, it is NOT caused by the electricity or anything like that, it is 100% of the time acid touching the metal and causing a reaction.
It is very hard, pretty much impossible to bond lead to plastic, most batteries are manufactured with an o ring embedded in the plastic to seal against the lead terminal. This often doesn’t help, acid wicks up and out.
Best thing to do is start off with disconnecting and cleaning the corrosion off of the terminals, install those felt anti corrosion disks, they soak up and neutralize the acid under the terminal where it’s coming from before it wicks up into the connection, protecting it, then spray it all down with battery terminal protectant, you’ll never have a corrosion problem after this.