Rotten Egg Smell from Car Battery

[Jonny Z]

I had a battery quit on me yesterday. During the last crank, it emitted a lot of rotten egg smell. I have never seen it before. What gives?

The battery was confirmed dead by a tester and was replaced. It was a Bosch.

 

[Pablo]

H2S build up.

Chances are she was worn out and couldn't do the H2SO4, PbSO4 thing anymore.

 

[Jonny Z]

Thanks.

 

[Pablo]

But it does make me wonder if it overcharging....

 

[Jonny Z]

Never charged it with a charger. It was cranking weak, and died. Jumped it twice and ran it for a while hoping the Alt to give it a good charge, but it never held a charge. On the last crank it was farting at me. Replaced it with a Wal Mart EverStart.

Never seen a Bosch batt before. This came with the used car.

 

[Pablo]

So age is unknown?

Sometimes when your alternator is not behaving well and not regulating properly you can boil the battery.

A quick check would be to check the battery voltage with car shut down (will be about 12.X volts). Then check voltage with engine running (and revving), should go up to about 14.1V max or so.

 

[toocrazy2yoo]

I like to remove the battery and see if the voltage drops substantially over the course of a day all by itself, no-load.

Most Alts charge 13.8-14.5vdc.

 

[DakAttack]

Bosch batteries are sold through pepboys around here. They are pretty $$$ compared to other batteries In my Opinion. They do offer a good warranty though. 3 Yr Free Replace. 3 Yr free Jump. Have never been able to find any Info online on them though.

 

[Jonny Z]

The charging was measured 13.8VDC at idle, so I doubt the alt fried the Bosch.

The car had been in storage in a garage for 3 month when my sister was at school, before the battery failed.

Myself and my friends have not been impressed by Bosch anything.

From experience they are more marketing than anything, almost Fram-like?

 

[Porkchopx]

It sounds like your battery had a couple of plates sulphate together and fail. Hence the sulphur smell on a high amp draw. Your voltage regulator in the alternator may be bad and overcharging your battery, boiling off the water or your battery was just due to die. Be sure to have the vehicles charging system tested when replacing the battery. Anything above 14 VDC is excessive and will cause premature battery failure.

 

[Jonny Z]

The batt looked new (clean). Exact age unknown. She had the car for 10 months.