Hissing battery

My John Deere 6620 combine had always started easily, but the last 2 or 3 days it has taken a charge with the battery charger and then a boost to start it. Seemed like it was always dead in the morning. It wasn't an immediate concern as I only had a couple of days of harvest left. I thought the alternator was getting weak. The voltage gauge in the cab was showing below normal in the red. The cab fan, header control, all lights, and air conditioner all worked fine. I had even harvested with the lights a few nights. I was prepared to take the alternator in to the repair shop to have it checked. This combine has 2 - 12 volt batteries in parallel. I thought the batteries were newer, but found '03 scratched in the top. So they were older. Fast forward to this afternoon. I had been working in the field and needed to make a repair on the head. When working on the head with everything shut down I heard a hissing sound. Originally I thought it was the radiator or the air conditioning cooling down. I climbed up and looked and found sort of a smoke coming out of the battery vent on the side. Sort of a pungent smell. The battery sides seemed bulged. With this condition I figured that this battery must have internally shorted out????? I unhooked the smoking battery and ran this afternoon with only the other battery. Running with this battery the alternator voltage gauge showed a normal charge. What do you guys think??? What was happening with the smoking/hissing battery??? Guess I will put two new batteries in an see what happens - maybe the alternator is OK afterall. Thanks.

I HOPE you wore eye and face protection while mucking around with that battery, as it could have exploded at any second. If you have ever witnessed a battery explosion, you would they are not SWELL!

Face it, a 2003 battery is pretty much used up.

After you in stall the new batteries, check the charging voltage to verify it is NOT over the 14 Volt range.

Yes, I was aware it could explode. My skin and eyes were covered.

Andy,

I think that you are right on - the battery has an internal short. My wife has a Ford Windstar van that the battery recently went bad in. It had such a strong sulpur smell, you could literally smell it from 30 or 40 feet away.

Are you going to replace both of the batteries? It probably would be good insurance to do so.

Tom in TN

If it were my combine I'd operate with just one battery. If you don't start engine in cold weather one battery will probably be fine.

A true Bubba story. Sealed Battery hissing, Bubba takes drill to make vent holes, you can guess the rest of the story, boom. Bubba here's your sign.

Had one blow up just after charging it. I thought I had lost my right hand, it hurt so much. My face was just off to the left of where the top of the battery went up. I ran to a sink and washed off the acid. Hung my coat up on a nail and in 2 weeks, it had fallen apart. Saw a school bus fender blown off one morning when the battery blew up.
I have much respect for them now.
Richard in NW SC

Sounds like you have a bad battery or 2 ?

They can become VERY dangerous and explode. You sure don't want that to happen while your near it as it will cover you with acid.

Be careful.

I see this a lot on trucks(I work for a large leasing co). If I have to jump start one the first thing I do is feel the batteries. If one is hot, it is shorted; I don't jump it, and I know that it drained the other batteries dead.THEY WILL BLOW UP. Be careful: wear protection. Mark

Bulging sides on a battery is often is sign the battery's acid/water mixture has frozen at some time in its life. A discharged battery can easily freeze.

A hissing battery could be the water boiling off from overcharging or heat. The steam often carries some of the acid with it as it leaves the battery. That battery is likely at the end of its life. I would rinse off the area around the bad battery before the acid causes rusting.

Is it still best to replace paired batteries as a set, or doesn't that matter anymore?

Change them both.

Lead acid batteries make electricity through a form of corrosion. Basically, one of the lead plates "rusted out" and came loose, shorting the battery. After 10 years, that's not really unusual. The battery was just plum wore out.

Next time you should probably pay more attention and replace the batteries before they swell and start smoking...

You know what's wrong, you done gone and let the magical smoke out of it.
Didn't anybody teach you that nothing works without the smoke inside of it.
Time to carefully replace two new batteries.

Get a full face shield, gloves and heavy clothing... and remove the battery immediately. if it's got caps, remove all 6 and dump it out. If not, break the bottom of the case and drain it. It's a bomb waiting for a place to blow. If it's shorting internally, and it probably is... and making hydrogen... and exposed spark will ignite the hydrogen.

Rod

All true. We become complacent with the familiar.
A battery contains stored energy waiting to dissipate it's self somewhere, somehow. An old worn out battery is even more dangerous.

George:

You don't have to be a Bubba to have that happen.

September 2002, I had just finished charging the battery in my pickup (battery totally disconnected & vent caps removed). Waited a half hour for battery to finish venting & reconnected battery terminals, Positive first. As soon as I touched the Negative cable to the terminal the battery EXPLODED, spraying me in the face with HOT battery acid. Garden hose was close by & I flushed my eyes out for about 20 minutes and everything seemed OK.

Unbeknownst to me, I had the very early stages of cataracts & the hot battery acid acted like a catalyst. Within 2 months I was TOTALLY BLIND. Normal vision is 20/20, legal blindness is 20/200, MY EYES were 20/400.

Over $14,000. and surgery on BOTH eyes, plus the fact that I will constantly have to wear glasses for the rest of my life, but I have my eyesight back.

A very EXPENSIVE and PAINFUL lesson learned!

Doc

I believe that the legal blindness numbers are for corrected vision, which is probably what you meant. I am 20/1000 corrected with glasses or contacts to 20/20.

Hello andy r,

You already found the problem.................. the smoking battery, Check the voltage at the battery to make sure it is not overcharging. It should be between 13.8 and 14.2 volts. Then go and get a new set of batteries,

Guido.

I would finish with the one battery then when I got ready next year replace the batteries. That way they are not setting wearing out all winter.

Eric:

Your probably correct, I'm just remembering what was told to me. It's a pretty traumatic experience when you've had good vision all of your life and then suddenly within 2 months your totally blind.

Doc