What is that SMELL ?

12.8 volts is fine if the batteries are just sitting there. 12.6 is actually considered 100% charged. Its what happens when you put an amp draw on them that determines if they're toast or not. That's why I have absolutely zero trust in these fancy digital testers. Load the suckers up to half the CCA rating for 15 seconds. If they can't maintain at least 9.6 volts at room temperature they're finished.

 

Please be carful when jumping or changing batteries when that smell is present.
The smell you smell is sulphur gas generated by the sulfuric acid from the defective batteries.
Sulphur gas is highly explosive and one spark from a jumper cable or battery terminal can cause an explosion that could cause severe injury or death.

 

Jumper cables on the dead battery first lessen the risk. Can't really arc good if there's no current flowing.

 

Absolutely, but always have to be aware if only one battery is sulphating the other two or three batterys hooked to the bank could have juice enough in them to make a spark....
I still have a plastic shard of a battery stuck in the beam of my twenty foot shop ceiling from an explosion from a battery that occurred over twenty five years ago.
I was a little Leary of that battery so I hooked up the battery charger and then pluged in the charger cord from a long lead cord and kaboom it blew up.
Thank god my head wasn't over it hooking the charger up that day.

 

That's crazy. I've never had a battery blow up on me. Hope it never happens.


Usually when I hook up jumper cables I do the dead battery first, then the positive on the good battery. Last connection I make is the negative on the boosting vehicle and its either to the frame or the engine block. Keeps the arc away from the batteries all together. Doesn't hurt to wave a clipboard or your hat around to try and dissipate some of the gasses that may have settled around the batteries as well.

 

Long time ago.
No smell.
No leaks.
Switch contact on.
Display lights up normally.
Turn key to activate starter.
BANG.........pieces from the sidewall off the battery go flying thru the hangar where i was loading.
The positive off the battery had broken internally,just below the top off the battery.
Which is the space where all the fumes are.
When it broke it made a nice spark in that gas.

 

My dad had a battery blow up in his face when I was about 5 years old. I watched it happen, in fact I thought I did it because he told me to turn the key on the Buick to try to start it and boom. He's holding his face and I'm running to the house for mom crying thinking I killed him.

 

Just embrace the fragrance.