Group 31 battery off-gassing

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I'm kind of backed into a corner on one of our fire engines. We have an International chassis which takes 3 group 31 batteries. All 3 were replaced back in October 25 as someone left the master switch on and killed them(they were around 10 years old). Within the last month we have developed a terrible rotten egg smell in the station. We called our natural gas technician and he identified one of the batteries as the source with a sniffer.

I suggested replacing all 3 however the local small town parts store we bought them from stated that there's nothing wrong with them(after only load testing) and will not warranty any or all of them. This truck lives on a battery maintainer like all fire apparatus and this is the only problem we've ever had. I did test the maintainer and the output is around 2-3 amps at 13.8 volts so I don't see how it could have damaged a battery. Truck alternator is working properly as well.

The smell goes away when they are not actively being charged. Hook up the maintainer or start the truck and the smell returns immediately. Am I correct to believe that we have either a cracked/damaged case or an internal defect in the battery that is producing the smell?
 
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There's a defect or Crack somewhere. You shouldn't smell any sulphur smell. Have you tried to using the color changing terminal cleaner? This should give you a sign of if or where a leak might be.
That's a really good idea, I will give that a try. Didn't think of the terminal cleaner.
 
I'm kind of backed into a corner on one of our fire engines. We have an International chassis which takes 3 group 31 batteries. All 3 were replaced back in October 25 as someone left the master switch on and killed them(they were around 10 years old). Within the last month we have developed a terrible rotten egg smell in the station. We called our natural gas technician and he identified one of the batteries as the source with a sniffer.

I suggested replacing all 3 however the local small town parts store we bought them from stated that there's nothing wrong with them(after only load testing) and will not warranty any or all of them. This truck lives on a battery maintainer like all fire apparatus and this is the only problem we've ever had. I did test the maintainer and the output is around 2-3 amps at 13.8 volts so I don't see how it could have damaged a battery. Truck alternator is working properly as well.

The smell goes away when they are not actively being charged. Hook up the maintainer or start the truck and the smell returns immediately. Am I correct to believe that we have either a cracked/damaged case or an internal defect in the battery that is producing the smell?
Take the "Stinker" back to them again. Walmart for future battery purchases.
 
Take the "Stinker" back to them again. Walmart for future battery purchases.
I am pushing them to use one of the OTR truck suppliers I use for batteries in the future as both of our local parts places are super high on 31s especially. Unfortunately we are roughly an hour from the closest Walmart so it's not quite as convenient as it is for many people.
 
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https://www.power-sonic.com/sla-thermal-runaway/

........When a short circuit condition occurs inside the battery, enough heat is generated to boil the acid in the battery. The sulfur odor – rotten egg smell – is an immediate way to detect if a battery is possibly experiencing a thermal runaway event. If you ever notice excessive heat or this smell, immediately disconnect the battery from any load or charger and stay away from it until the battery has cooled.....
 
had this happen with a battery that had an internal short of some sort.
It would get so hot you couldn't touch the terminals and had a very noticeable smell
 
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had this happen with a battery that had an internal short of some sort.
It would get so hot you couldn't touch the terminals and had a very noticeable smell
Yeah I had one like this as well, it tested at 10.5 volts just sitting there as one cell was a dead short between two others. Since it was still charged at 14.5v, this meant every other cell was overcharged by 6/5 and venting grossness.
 
I'm kind of backed into a corner on one of our fire engines. We have an International chassis which takes 3 group 31 batteries. All 3 were replaced back in October 25 as someone left the master switch on and killed them(they were around 10 years old). Within the last month we have developed a terrible rotten egg smell in the station. We called our natural gas technician and he identified one of the batteries as the source with a sniffer.

I suggested replacing all 3 however the local small town parts store we bought them from stated that there's nothing wrong with them(after only load testing) and will not warranty any or all of them. This truck lives on a battery maintainer like all fire apparatus and this is the only problem we've ever had. I did test the maintainer and the output is around 2-3 amps at 13.8 volts so I don't see how it could have damaged a battery. Truck alternator is working properly as well.

The smell goes away when they are not actively being charged. Hook up the maintainer or start the truck and the smell returns immediately. Am I correct to believe that we have either a cracked/damaged case or an internal defect in the battery that is producing the smell?
A battery that stinks when charging is on its way out.
Also, how did they test them?
 
All I was told is that the shop "load tested" them. I wasn't there when this happened.
Then I bet this is what happened.
They drove the vehicle to the auto parts store. The store person took the tester, connected the test leads to each battery and they all tested good. Because they never unhooked anything and all 3 batteries are feeding power to the tester and the parts store people are only used to testing vehicles with one battery.
The proper way to test lead acid batteries in a nut shell is charge them fully, let them sit at least 8 hours at about 70f, no charging or discharging and most important of all, test them individually...

People who have big battery equipment that uses group 31 or those double group 31 sized tractor trailer batteries remove them and take them to the parts store to be tested.
 
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My vote: I’m pretty sure one cell is toast and overcharging any time a charge is presented to the battery. That one weak battery will quickly drag the others down when no charge is presente.
 
If you’re a fire department and you come into my parts store trying to warranty a battery that’s still under warranty, it’s getting warrantied, no matter what the battery tester says.

Anything different is absurd. Talk to the owner or manager of that place!
 
I am pushing them to use one of the OTR truck suppliers I use for batteries in the future as both of our local parts places are super high on 31s especially. Unfortunately we are roughly an hour from the closest Walmart so it's not quite as convenient as it is for many people.
Batteries cost 40% less from Walmart. That might be worth an hour drive, especially if you're buying 3 at a time. Walmart Everstart batteries are good.
 
What about the water levels of the suspect battery? That smell is hydrogen sulfate which is usually caused by overcharging. I would look for cells with low water and also check the alternator voltage output. It may be excessive and has cooked the weakest cell.
 
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