Ok I am trying to help a friend out but this one is stumping me I think it may be his voltage regulator on his alternator overcharging the battery. But I was hoping that someone has had this happen to them and can let me know the 411 if it was a alternator. Never had this happen on a honda before, but it could. The car is a 99 4 Door EX, roughly 70k on it.

 

did u check charging voltage?

 

happened on a volvo i drove...the battery was leaking and considering the acid is sulfuric...that would explain the smell.

I had to replace the battery though.