07-02-2019, 02:14 PM
My wife calls me at 3 am from our boat complaining of a terrible rotten egg smell, she even threw up several times it was so bad. The next day I arrived and immediately assumed it was coming from the ac drain pan that was overflowing due to a faulty float switch in the shower sump. After replacing the switch and cleaning out the pan as best I could using bleach and bilge cleaners we left the boat opened up to air out for several days. I used it for a fishing trip and all seemed well until we plugged the shore power back in and started the a.c. unit back up and the smell quickly returned. Still convinced it had to be the a.c. unit I removed the whole unit from the boat and opened up all the hatches for a few hours but the smell was still there. That's when I notice that the battery charger is running non stop and the smell is almost as bad in the engine room upon inspecting the batteries for leaking and not seeing anything I put my hands on each one and one of the four is hot to the touch and obviously is where the smell of hydrogen sulfide was coming from. All the batteries were replaced two years ago with Interstate group 31 maintenance free lead acids. I guess my next project will be to replace all batteries with agm models as I had no clue that the a.c. unit could even draw intake air from the engine room where the batteries reside. This seems like a very dangerous setup as no smoke or carbon monoxide detector will pick up anything like the fumes from a overheating battery. It was so bad people driving by in other boats wondered what the smell was.