Sometimes, lead acid batteries give off a foul odour which resembles the smell of rotten eggs. The Rotten egg smell is the characteristic indication of the presence of Hydrogen Sulphide (H 2 S). Faulty batteries tend to get overcharged.
Battery acid commonly smells like rotten eggs but may smell differently depending on type (we have a chart below). Yup, you heard that right – pretty gross, huh? This stench is mainly due to hydrogen sulfide gas, produced when a battery dies or leaks.
This aroma is caused by the release of hydrogen sulfide gas, a byproduct when the sulfuric acid within lead-acid batteries overheats. This overheating often results from battery malfunction or overcharging. Key culprits behind overcharging are a malfunctioning alternator or a defective voltage regulator.
Just make sure your battery is in a well-ventilated area to disperse the smell and minimize any risks. Old and dying batteries can also create that nasty battery acid smell. When a battery ages, it loses its ability to hold a charge and might even emit a funky smell.
Flooded lead-acid batteries are way easier to tell if there’s an overcharge issue. Still, even sealed batteries have a pressure relief valve if the overcharge is too much and you can still smell the rotten egg smell on them. Is the Rotten Egg Smell from a Battery Dangerous?
A bad car battery can produce a distinctive odor akin to a foul egg. This aroma is caused by the release of hydrogen sulfide gas, a byproduct when the sulfuric acid within lead-acid batteries overheats. This overheating often results from battery malfunction or overcharging.