I have a double battery set up (not leisure) as my MPV was built to operate in cold regions - had a little bit of corrosion over time. Last inspection a few months ago I had to replace the earth terminal on one side. I was doing routine check today and noticed the terminal had crud on it. I took it off to inspect and clean the battery. The earth post on one of the batteries has been badly eaten, the clamp has been almost eaten through.
Is this a signal that the battery has had it and is undercharged (refusing a charge)? Other than that no starting problems and no charging light - has me stumped but looks like its going to replacement clamp and also the errant battery. I consider lack of any problem of corrosion of that other battery terminals, earths linked so earth to body is common to both batteries.