sulfur/rotten egg smell=bad battery... Who knew?

[996scott]

Just an FYI for anyone in case it happens to them in the future. Last week was out boating and as soon as we were on the water i smelt a "sulfur" smell. It came and went most of the day and at times was kind of strong. I kept wondering if it was the boat or just the lake. I could not figure it out but definitely thought it was the boat. Got home and cleaned up the boat and didn't notice anything at all, no smell at all, so i figured it was the lake. No smell at all in the garage all week and even when i was back in the boat loading up this morning to go out again. Got to the lake and as soon as we were on the water i smelt it again! It was driving me crazy and everyone agreed it had to be coming from the boat. We finally pulled every seat and looked/smelled around and the strongest smell was from where the batteries were. My son googled it and there was a lot about batteries having a bad cell and giving off a sulfur smell when charging them. We got home and cleaned out the boat and again no smell at all anywhere! My son suggested we hook up the fake a lake and run the boat for a few minutes. Within 20 seconds of starting the boat the smell was back. Sure enough one of the batteries was really smelly if you got right up to it. Everything looked fine from the outside of the battery, no corrosion. Maybe a tiny bit of water around the cap but not much at all. Anyway, i pulled it out and got a new one so i will see what happens next time out but i had never heard of sulfur smell being an indication of a bad battery. Just thought i would share in case anyone comes across the same problem.

[MLA]

What was the water level in each cell? Hope you looked prior to turning the "bad" one over for exchange. I would get a volt meter and check the alternator output at the batteries, prior to hitting the lake again.