Oxidation
I Have had the same problem and agree with laurapasinifan
The battery is Off gassing and the older the battery the more the Off gassing.
And thus the faster the Corrosion on the terminals .
Buy a can of Spray on Terminal Protector and Spray it once a week or so to prevent the Corrosion. You will still, even with that , from time to time have to use a Brush terminal Cleaner to Scrape down the Terminals.
If you are in Sosua , Bring the vehicle to us at Battery Klinic and we will take a Look and Shoot ya a Free Spray !
I Have had the same problem and agree with laurapasinifan
The battery is Off gassing and the older the battery the more the Off gassing.
And thus the faster the Corrosion on the terminals .
Buy a can of Spray on Terminal Protector and Spray it once a week or so to prevent the Corrosion. You will still, even with that , from time to time have to use a Brush terminal Cleaner to Scrape down the Terminals.
If you are in Sosua , Bring the vehicle to us at Battery Klinic and we will take a Look and Shoot ya a Free Spray !