Why's my battery steaming out the vents? Why's it smell like French fries?

Chrishart749@gmail.com

Original poster
Member
Mar 25, 2015
13
So I started my truck and it smelled like sulphur.. And i shit my pants thinking it was my cat because I just replaced my fuel pressure regulator yesterday.. Anyway.. Few miles later I'm dropping the kids off and it smells like French fries! I actually walked around to my tail pipe to see if someone jammed it with a potato .. Then I sniffed around and tracked down the smell to under the hood.. Popped it and my battery is sizzling and steaming.. Wtf? So I shut it off slammed the hood and ran in to write this.. Well I did pour a vodka and lemonade first.. ;-) no more workin on cars tonight lol..
I've currently got my trailblazer jacked up taking off the original sway bar end links.. Even the big boy tools couldn't get that bolt off so I resorted to cutting it off.. It worked well and I'll just have to pull the whole sway bar to start re installing the new ones.. And it's also making a fan related noise after fan clutch and water pump.. Needless to say I'm stressed out .. Anyway.. The trucks been having a slight shift issue and I'm 75% sure it's the Ecp solenoid. But it was getting progressively worse then normal when the smell became apparent .. Focusing on the silverado not the tb.. Silverado is dd
 

kickass audio

Member
Aug 25, 2012
955
you overcharged the battery. double check the voltage when your truck is running. it should be around 14.4-14.6v. if its too high, you overcharge the battery and they vent like they did by blowing out the gas. DO NOT SMOKE or anything around that battery, one spark and the hydrogen gas can make an explosion and hurt/kill you. you may have a bad regulator on your alternator for it to do that and it can be frying the computer in the truck with too high of a voltage on the system.

edit: you may also be shorting out the battery somewhere and that is making it draw so much amperage that it is making the battery vent. check for any broken or shorted connections on your power wires.
 

IllogicTC

Member
Dec 30, 2013
3,452
Something like this?

[media]https://www.youtube.com/watch?v=hvvwFgQucxA[/media]

Could be a few things.

  • The vented tubing is clogged, preventing air flow to the battery and making the shroud a little nest for toxic or even explosive vapors that come from common lead-acid batteries
  • The battery has been allowed to run low on water. If it's not a maintenance-free battery (and therefore has some spots on top where you can open the battery, there'll be six holes when the plugs are removed) it's necessary to check the battery's specific gravity as a periodic service, and ensure that all cells are maintained full of distilled water.
  • The big top suspect I have, your alternator is failing. They have an internal voltage regulator, meaning that while at 600 RPM it's putting out say 12 volts and at 3000 RPM it's putting out say 25, it is always regulated to a target, generally in the 14 range (13.8-14.2 ideal). According to Ye Olde Internet, apparently an overvoltage condition of even 15 volts output can put your battery at risk of overheat.
What did your battery meter say when the truck was still running? I wouldn't advise going and starting it now, that battery is a hazard. You'll want to wear adequate Personal Protective Equipment, as you're dealing with sulfuric acid here. The battery is likely toast either way and needs replaced, but you should also remove your alternator and have it tested.
 

Chrishart749@gmail.com

Original poster
Member
Mar 25, 2015
13
so if problem gets solved is that battery usable?
 

Chrishart749@gmail.com

Original poster
Member
Mar 25, 2015
13
Oh.. Okay. I was leaning towards alternator too
 

Chrishart749@gmail.com

Original poster
Member
Mar 25, 2015
13
Luckily I have a couple extra batteries.. Will replace alternator and see what happens.. I've been thinking it was bad for a couple days because it keeps acting exactly as it did once I accidentally left it unplugged. Thanks guys you're always appreciated
 

IllogicTC

Member
Dec 30, 2013
3,452
Chrishart749@gmail.com said:
Luckily I have a couple extra batteries.. Will replace alternator and see what happens.. I've been thinking it was bad for a couple days because it keeps acting exactly as it did once I accidentally left it unplugged. Thanks guys you're always appreciated
When you left the battery unplugged while running? Yeah, it may very well be similar in terms of symptoms. As The Roadie explained it to me, in a system like this the battery helps to keep the output of the system under control, without that there it may go a bit whacky. Use one of your extra batteries to start her up and get a measurement with a multimeter of alternator output if you'd like some homebrew confirmation, or just take it up to the auto parts store, they usually do that testing for free since if it's bad you're in the right place anyway!
 

Chrishart749@gmail.com

Original poster
Member
Mar 25, 2015
13
No, not the battery.
The alternator! I started it up with the alt unplugged( not to the battery, the electrical connector) and it revved on its own and felt like I had the tps unplugged.
Similar actions have re-occurred.
Will purchase multi meter now.. Switch batteries and test. What am I looking for at idle after start up? Basically what's my sign to turn it the hell off before I ruin a 2nd battery?? At least I'd know it was the alt. but that's plain wasteful
I know it could very well be a dead cell in my battery..
 

AWD V8

Member
Jan 12, 2015
463
You want to see 14.2-14.5 volts when running. Anything over that is not good. Over 15 volts is bad.
 

Chrishart749@gmail.com

Original poster
Member
Mar 25, 2015
13
I took the alternator to autozone and had it tested.. Like 4 times.. It passed every time.
I'm going to assume that leaves me with a bad battery.. I'm going to spray some maf cleaner on the elec. connector of alternator and switch batteries. Start it and test with multimeter. If volts look right I'll assume success. Thanks again.
Abt 3 years Ago I switched to gm products from ford... Because everyone always ragged on me abt my fords and that I should buy Chevy. So I did and now I have three Chevys in the driveway.. Gotta say they build these with much more difficulty to replace simple parts. The thermostat on my trailblazer took forever .. F150 it took 5 minutes. I've broken the trans in every vehicle in said driveway. Twice in the SS ;-)
This time I learned and it would take twice my motors power output to break this one! I've had nothing but trouble but they're just so much more enjoyable to drive.. I fell in love and for some reason it's worth it. But damnit gm why can't we have good quality shit that we can replace simple parts easily? Oh right. Gotta pay back the government somehow :-/
Sorry just my angry rants as I try to figure out just how that sway bar pulls all the way out on my tb. But now that it's loose I guess I've got enough room to cut off the tops as I did the bottoms..End links were bad but had to be cut off.
 
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Chickenhawk

Member
Dec 6, 2011
779
Once you smell a battery overcharging, you will never forget that smell. It is unmistakable. If that is what is happening, you MAY be able to save the battery, or it may have boiled dry and run for too long. If you keep driving, you run the risk of frying some very expensive electrical components. Test your voltage. An alternator test at a parts store might or might not tell you the regulator is gone, because some tests are just simple yes/no tests to make sure it is putting out a minimum charge.

And, as others have warned, be VERY CAREFUL. That gas coming from the battery is very explosive. I had one blow up near my face 30 years ago. I never want that to happen again.
 
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Chrishart749@gmail.com

Original poster
Member
Mar 25, 2015
13
I was just waiting for someone to reply because I don't see the edit button and I found out the hard way not to post more then once in a row.
The test at autozone apparently considered the regulator too
I put a battery in there and it was fine. It was an ac delco and it says warranty 6 yrs some odd miles.. And has a bar code. If battery was still under warranty as I believe it was. Can I manage a free one from a dealer?
 

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