Michael - Please stay with the group and don't let one person's rude comments put you off. It's clear you know what you are doing.
Here's a thought - The steel frame that clamps the battery in place is perilously close to the positive battery terminal. If the clamp loosens and touches the terminal you have a direct short to the frame of the car. Of course, this would result in a fire, however I'm wondering if crud/oil/grease etc on the positive terminal could be causing the leak by offering a high resistance path to earth. Just a thought, but worth checking. I've wrapped the clamp with insulating tape on my car, where it gets close to the positive terminal.
Here's a thought - The steel frame that clamps the battery in place is perilously close to the positive battery terminal. If the clamp loosens and touches the terminal you have a direct short to the frame of the car. Of course, this would result in a fire, however I'm wondering if crud/oil/grease etc on the positive terminal could be causing the leak by offering a high resistance path to earth. Just a thought, but worth checking. I've wrapped the clamp with insulating tape on my car, where it gets close to the positive terminal.