My Coachmen Freedom express has been plugged in since I de-winterized it in April, the battery (new in 2014) was stored in the garage (heated) over the winter. Over the last week I've noticed a sulfu...
If the battery has a shorted cell the converter sees the low voltage as a discharged battery and puts a lot of current into it. This boils off the remaining good cells and that's what you smell. I'd pull the battery and get it tested.