If you smell sulfur, please check your battery!

[Xist]

Mom had been complaining her garage smelled for a month or two. She said she figured out it was the car, then the engine compartment, but I never smelled anything. I still did not smell anything when I popped the hood, but one of the battery terminals was corroded. I did not think it was that bad and we were four hours behind schedule leaving on a trip.
We drove 163 miles to the Phoenix area and when we first stopped at a light we heard some grinding or roaring sound. We did not have any idea what the problem was. I drove to the hotel, and parked in front while we checked in, but then the car would not start. I cleaned the terminals, got a jump, and started driving to charge the battery, but the battery light was still on.
At some point I smelled sulfur, but just once. The alternator was loud because it was dying. Someone said it needed to work harder, but the bearings could have been going out.
I just thought someone might not know all of the above and it might help them. I hope everybody has a great night!

[JockoT]

The electrolyte in a lead acid battery is H2SO4 (Sulphuric acid). If you brew that up, you get a smell of sulphur from the vapour. It also attacks battery terminals and any other metalwork in the vicinity.

[Stubby79]

Sounds like a lesson learned. Time for a new battery and alternator.

These things are avoidable, if you pay attention to the signs and give your car the attention it needs.

The only battery I've had to replace in a running car was in my first car a good 20 years ago, when I was a teenager and still new to cars. It was having a hard time cranking over the engine, ran a bit rough and killed the fuel mileage. A cell had died in the battery. Still started and ran with just 10v on it, thankfully. The signs were there, I was just too new to cars and engines to recognize the signs.

And, yes, if you smell sulfur/rotten eggs, check your battery. I smell it at work when someone over-charges a battery on our lift equipment, and I've smelled it when a charger wouldn't shut off on my first electric bike and cooked the battery. Fun stuff.

[kafer65]

Bad voltage regulator caused this smell by boiling all of the water out of my battery. Alt was making over 18 volts!

[Xist]

That is not a small number! That is a large number!

[ksa8907]

I had a similar experience lately, my wife's 2012 traverse with 76k miles on it needed a new battery and alternator. The manufacturer placed the battery inside but with venting and still used a flooded battery(possibly was not factory). Battery boiled the fluid to the point it lost capacity and the alternator overworked itself to failure.

$300 later for a new AGM Battery and new alternator...

[Stubby79]

Originally Posted by Stubby79

The only battery I've had to replace in a running car was in my first car a good 20 years ago, when I was a teenager and still new to cars. It was having a hard time cranking over the engine, ran a bit rough and killed the fuel mileage. A cell had died in the battery. Still started and ran with just 10v on it, thankfully. The signs were there, I was just too new to cars and engines to recognize the signs.

I spoke too soon! Battery croaked on my gas Firefly today.

Well, it was pretty much dead a few days ago when I charged it up for the first time in a couple of months. Ran fine for a few days, then just didn't want to start after sitting for all of 8 hours at work. Jumped her, brought her home and quickly discovered it wouldn't take/hold a charge. Good thing I have a spare.

It had a pretty good run; it was manufactured 7 years ago last month. I wonder if that's a coincidence... I'll have to see if that sticker on it says 72 months or 84. (I know I've seen an 84 month one on one of my batteries). Pretty suspicious!

[bestia]

Hi. I'm new here.

Yes, what you were smelling is hydrogen sulfide gas which has the rotten egg smell. Lead acid batteries produce hydrogen gas when charging--a spark from jumper cables can cause the battery to explode throwing sulfuric acid everywhere.
I had a battery blow up a foot from my face. Fortunately a fellow mechanic hit me with the water hose and I have no scars.

[teoman]

I have had success revibing batteries by charging them for a week.

[cRiPpLe_rOoStEr]

Originally Posted by bestia

Lead acid batteries produce hydrogen gas when charging--a spark from jumper cables can cause the battery to explode throwing sulfuric acid everywhere.
I had a battery blow up a foot from my face. Fortunately a fellow mechanic hit me with the water hose and I have no scars.

That's a reason why I prefer to disconnect jumper cables only when one of the vehicles had already been shut-off. And actually I prefer to avoid resorting to jumper cables anyway.