OT Car Battery Explodes

You didn't say or imply it was the same design as an auto battery, you identified it _as_ an auto battery. That makes readers think that you don't know what you are talking about.

Now you label the design as defective, implying that you think you know more than the battery designers.

You implied the same in an earlier post where you wrote: "Over the last few years, it has become clear to me that many 'professionals' provide information that is dangerously incorrect."

What you originally objected to was: "Wash and clean the battery, battery terminals, and case or tray with water. The corrosive acid can be neutralized by brushing on some baking soda (sodium bicarbonate) solution. If the solution does not bubble, the acid is probably neutralized. Rinse the battery with water to remove the baking soda solution."

Now you omit the last step - yet in your previous post you advocate rinsing the battery with clear water.

You seem to be grasping at straws, desperately trying to find some way to get some amount, however miniscule, of baking soda into the battery. Just how often does your car owner's manual or battery manufacturer's instructions tell you to fill your modern battery? Or is your "thoughtful maintenance", that ignores your own recommendation to rinse the battery with clean water, based on something else?

Oh, my. Reverse charging a cell in a lead acid battery?

What amount of baking soda is going to get into a battery cell in the maintenance scenario you mentioned above? How much will that amount weaken the acid concentration in the cell?

What method(s) have you used to determine that it is normally the result of a weakness in just one cell? How have you measured the individual cells? What sample size allows you to determine that the word "normally" (which you emphasised) is appropriate?

First, you need to be specific about what you mean by "a weakness". Second, you need to be specific on the method(s). Third, you need to define the sample size required to determine what the normal failure cause is.

Did you purposely ignore "We're not talking about a battery that has been uncapped.", or did you simply miss reading it?

I not only don't own one, I don't even play a NAPA shop owner on TV. :-)

You believe and imply that you know more about correct battery design and maintenance than the professionals. Perhaps you do, but given the opportunity to post data to back up your belief, all you've offered is handwaving and bobbing and weaving.

Ed

For the purposes of the discussion it is form, fit and function the same. You could drop that battery into a car with little or no modification and it would work properly.

I agree that it is not the best possible battery for every possible car.

Is this an issue?

I know considerably less than the designers do. The designers only follow the instructions given to them by management. I feel the design is defective in terms of longevity for it's intended purpose. I think the managers are completely aware of that fact.

Think 'Challenger O-Rings', but less dangerous and 'way more profitable.

:)

I was attempting to imply that these 'professionals' were deliberately providing dangerously incorrect information for their own venal profit, not necessarily out of stupidity or ignorance.

Yes. Simply rinsing the top of the battery is not guaranteed to remove enough of the base. The problem is not the clear-water rinse. The problem is bringing a base anywhere near a lead acid wet cell battery. It is unnecessary and uneconomic.

The combination of the 'funnel top' battery design and bringing a base into contact with that battery is what I find objectionable.

Let me come at the issue in a slightly different way.

You are idly thumbing through a magazine at the dentist's office and are nonplussed and appalled to see a discussion of what shampoo to use to clean the gasoline out of your toddler's hair after his morning dousing. Your first reaction might be 'golly it is totally unnecessary to douse a toddler in gasoline at any point in the day! Why are these folks discussing the proper shampoo to rinse the Ethyl out of little Johnny's tresses?'

The douse is unnecessary and uneconomic (at the very least!) We don't really need to discuss whether a *cup* of 85 Octane is safer than a whole body drenching. My point is that *any* is 'way too much.

Ya see where I'm headed with my subtle metaphor?

My goal is to *prevent* the addition of baking soda or anything that is not distilled water into any battery cell as part of routine maintenance. Have I not made that point sufficiently clearly?

It would not take much bicarb to make the battery fail. Bicarb and car batteries are not a good combination.

In another week or so, I will be running thin on ways to present the concept.

About never. What's your point?

Sure! My example (of the owner removing the battery caps and swabbing the top of the battery with a slurry soaked rag) is something that I can see someone doing quite readily.

Our Internet Experts are telling him that it is OK to swab a bicarb slurry over the top of the battery, so it couldn't be inadvisable to just go the extra step logically, yes?

USENET and the Internet is a marketplace of ideas. There is a lot of 'garbage info' present in both. However, I've discovered a lot of interesting information on USENET and the Internet. I appreciate it when others point out flaws in that information because it stimulates me to think about the subject at hand.

As a denizen, I feel an obligation to help others the same way. I think you do, too. Otherwise we would be talking about politics.

Yes. The resistance of a weak cell can increase so much that the cells connected in series with it will tend to bias it backwards. That is when we buy a new battery.

Too much, likely.

That is up to science to reveal, and that research would be kept confidential, IMHO. Any quantity will tend to imbalance one cell in relation to the others, reducing the reliability of the battery, IMHO. I don't know if there *is* a dose that is small enough to leave 50% of treated batteries unaffected.

Measurement of the voltage of each cell in the battery. Measurement of the comparative specific gravity of electrolyte in each cell.

Multimeter set for 'D.C. Volts'.

I do a quick inspection of every battery I replace. Without exception, they tend to have one cell that is at significantly lower voltage than the rest of the cells. That is normally what I see; I have not seen a variation in that trend.

One or more cells at significantly lower voltage than the rest of the cells in the battery.

Cell voltage measurement and specific gravity comparisons.

Ideally, a complete postmortem on every battery that has ever failed. I limited my sample to just those batteries I've replaced over the years.

As I mentioned previously, a tap water rinse will not necessarily remove enough base to be economically safe. On the next battery service, that dried base is very likely to fall into the uncapped cell. Bases should not be applied to the case of a battery. It is unnecessary and uneconomic.

Me neither. :)

No. The battery designers forgot more about lead-acid chemistry during lunch last Thursday than I will ever know. They are constrained by Management to do things that are not necessarily in the best economic interest of the customer. DAGS on 'planned obsolescence' for example.

I agree that it would be much better to do the science and settle the question. Everything I have said comports well with objective science, IMHO.

I offer a maintenance method that is safe and economical on any kind of wet cell lead-acid battery as an alternative to an obsolete method likely to shorten the life of a large portion of modern wet cell lead-acid batteries.

--Winston

--- If you don't know, then that compounds the absurdity of the situation.

From a few sentences down:

"If you know that the slurry will dry and leave baking soda powder around the filler caps, then it seems if one would think about it a little one would hose off the slurry until only water was left around the filler caps, the result of that being that when the water evaporated, Voila, no residue."

The stupidity lies in not taking the preventive measure of thoroughly rinsing a battery with water after exposing the battery case to a baking soda - water slurry, when one knows that when the water evaporates from the slurry the remaining baking soda can inadvertently fall into a cell when its cap is removed and believes that will damage the cell.

---

--- I said that further down, with repect to the Na2SO4 generated by the H2SO4 - NaHCO3 reaction, not to the hydrogen ion lost by the H2SO4 during the reaction.

As a matter of fact, if the reaction ran to to the point where there was no baking soda left on the surface of the battery, the white, crystalline material present would be Na2SO4 and if it fell into the battery would not affect it one whit.

---

--- had you rinsed the battery properly after using the slurry, the answer would be obvious.

Whether a cell was "damaged" or not depends on how much NaHCO3 was allowed to fall into it and how long before the lost acid was replenished.

---

--- Nonsense.

Since a lead-acid battery loses acid during normal operation, that acid can settle out onto the battery case and holder and a simple rinse with water won't determine if all of the acid has been washed away.

A simple way around that problem is merely to neutralize the acid with baking soda or a baking soda - water solution and to follow that up, when the fizzing has stopped, with water rinse.

---

--- Nonsense, see previous.

---

--- Where on Earth did you get that from???

Let's look at the reaction again:

H2SO4 + 2 NaHCO3 --> 2 CO2 + 2 H2O + Na2SO4

First, notice that what we start with, on the left hand side is sulfuric acid, H2SO4, and sodium bicarbonate, NaHCO3.

Second, notice that there's an H2 in the H2SO4; that's what makes it an acid.

Now, if we start with 1 molecule of H2SO4 and 2 molecules of NaHCO3 and mix them together, the electrons around the atoms will be very unhappy and will rearrange themselves into states that make them happier.

At the end of the process, the 2 sodium atoms from the baking soda will have joined up with the sulfate ion from the sulfuric acid and formed the salt, Na2SO4, sodium sulfate.

That leaves us with 2 hydrogens from the H2SO4, 2 more from the

2 NaHCO3, and also from the 2 NaHCO3, 2 carbons and 6 oxygens, all unhappy alone.

So, they hook up with what they can and we wind up with 2 CO2 molecules, (which uses up the 2 carbons and four of the oxygens) and 2 water molecules, which uses up the 4 hydrogens and the remaining 2 oxygens.

So, in the end, we will have neutralized the acid by changing it into a salt as well as having created CO2, which will bubble away, and H2O, into which the salt will dissolve, yielding an aqueous ionic solution with a pH of 7.

---

--- I never said it wouldn't.

---

--- I see.

---

--- Well, heretic isn't exactly what I had in mind, but yes, of course it would.

---

--- Why?

The cells are each chemically independent, with their own cache of electrolyte, and we know from the chemistry described earlier that any acid neutralized is turned into sodium sulfate, carbon dioxide, and water, so the net effect of adding baking soda to the electrolyte is that of taking some acid out of the cell and adding some water, thus raising the pH.

In order to lower the pH, then, it seems like (since the sodium sufate is neutral, as far as pH is concerned) adding enough acid to lower it to the value of the pH in the other cells would do it.

But, since testing pH is tricky way down there, I'd probably just use a hydrometer and be done with it.

---

--- "neutralization of the cell"???

---

--- Damage to a battery is unavoidable and cumulative in normal use, so if you dropped a couple hundred milligrams of baking soda into a cell and as much acid was neutralized as could be, and then you added enough acid to replenish what had been lost plus whatever extra was needed to compensate for the extra water made by the baking soda, why would the cell deteriorate in other than a normal manner?

--- JF

Let's agree to disagree about the wisdom of exposing a lead acid wet cell to a basic slurry. I will not change your mind on the subject and you will not change mine.

I am certain that a tap water rinse is not guaranteed to remove enough of the base and you are certain that a tap water rinse is not guaranteed to remove enough of the acid. :)

September 4, 2010 at 10:29 AM local time, someone calling themselves "John Fields" said: "The Na2SO4 should be innocuous since it won't even change the pH of the solution,.."

Perhaps that wasn't you with the misleading statement, John?

(...)

Today the pH neutralizes! Good. We agree at last.

Perhaps it wasn't you? Or is 'never' shorter than 1 day long? September 4, 2010 at 10:29 AM local time, someone calling themselves "John Fields" said: "The Na2SO4 should be innocuous since it won't even change the pH of the solution,.."

Perhaps that wasn't you with the misleading statement, John?

Now we are getting somewhere! :)

Adding a base to the acid in the cell tends to neutralize the acid, yes? Even this afternoon? The cell is compromised and does not perform nearly as well as it did before. The resulting 'sulfation' is likely to progress to the point that the cell (and the battery it resides in) will be discarded.

If that ain't 'neutralized' then what is? :)

Yes. I agree. The effect of a few molecules of baking powder can probably be overridden by a good equalizing charge.

Because the battery is highly likely to undergo several charge / discharge cycles before the pH of the affected cell is corrected. I assume that sulfation would have caused irreversible damage to the cell by then, as you implied earlier. I expect that the battery would be tossed out before the pH were ever corrected. I have never even attempted to 'repair' a battery in that manner.

Perhaps you have?

--Winston

--
What's misleading about it?

Will adding Na2SO4 to the electrolyte change its pH?

One final swat, bicarbonate of soda is a weak acid. Dissolve some in water and measure the pH (before and after if you need to).

I've reduced the file sizes and add another photo related to the venting of the battery. See ftp://ftp.meraka.csir.co.za/pub/in/Battery_Explode/

The battery does not vent through the filler caps but through a vent on the side. There seems to be a vent channel that interconnects all 6 cells and exits through a single vent at the right hand (positive pole) side of the battery. The vent hole is sealed on the negative pole side of the battery. I photographed the vent after I found it and dropped it on top of the battery.

This vent was blown off during the explosion and was picked up from the floor. It has been slightly dosed with baking soda in nutralising the acid on the floor. The vent wasn't blocked after the explosion :-).

Any gas generated in the one cell could spread to all cells in this type of design. A hot spot in any of the cells could therefore ignite the gas. Interconnecting the vents between cells could therefore enhance the chance of an explosion.

This type of venting does have its benefits. It prevents acid residue forming on top of the battery and helps to keep acid from collecting on the battery poles. It also helps to prevent ingress of dirt and other stuff from the top surface of the battery. I haven't cleaned the battery top before I took the photos and it provides some proof that this venting design keeps the battery top free of acid residue.

Regarding the origin of the battery. I could not determine where the battery was manufactured. We have or use to have a local Willard factory but I doubt that they manufacture all Willard battery models.

Many thanks for all the feedback on the possible causes of the explosion. There seems to be a couple of possible scenarios that might result in the rapid disassembly of a lead acid battery when connected to a heavy load.

Gerhard van den Berg

Who cares? Dancing around the cell naked won't change it's pH either.

It is doubletalk to *imply* that the pH of the cell would not change as a result of the addition of a base by saying that a separate chemical change would not *in itself* cause the pH to change.

Look, we've made real progress here. Let's not backslide.

"Neutralize" means "to make inactive or ineffective". We agreed that the cell would be damaged. A damaged cell is in the process of becoming inactive and ineffective.

We agree two days in a row! Wonderful!

Yes. Who cares?

I was just asking if we still agreed or not. Apparently we do. Good! :)

(Whoops. Spoke too soon.)

Yup. Increasing the pH of the electrolyte in that cell will imbalance the performance of the cell vis a vis the other cells in series with it. This will result in accelerated damage and eventually the early failure of the battery as a whole, as compared to the reliability of a properly maintained battery.

Have I really been pompous or patronizing John? :)

Because I have other, more important things to do with limited resources and time. You do as well, I assume.

Got me! Baking soda is the correct term. Forgive my hyperbole. The fact remains that bases and wet cell lead acid batteries don't mix.

Real life is different from theory. Our hapless consumer wasn't even aware that he caused the battery to fail earlier than it would have had he though more carefully about putting a base on top of it. (Battery manufacturers like that.)

We agree the cell would be damaged and the battery as a whole would fail earlier than it would have otherwise. Good!

(...)

Neither of us has the time, resources and inclination to do the real science, and we both have much better things to do with our lives than to produce a conclusion that is likely to raise the attention of the rich and powerful.

Let's agree to disagree (occasionally).

--Winston

Compared to battery acid, Sodium bicarbonate is basic (more alkaline).

Sodium bicarbonate is an amphoteric compound. Add it (in solution) to either an acid or to a strong base and it will tend to push either mixture toward neutrality (pH of ~ 7).

Is that incorrect, Joseph?

--Winston

The ends of the container have not been displaced very far, which suggests that only a small volume of gas was involved in the explosion.

With a sealed battery, or one which only vents under pressure, the space above each cell will retain the stoichiometric hydrogen/oxygen mixure resulting from charging for a very long time. This is almost certainly what exploded - but the question is "why".

If an internal connection of the battery had become unsound, the heavy starting current would be the first thing to show this up. The mass of metal in a high resistance joint might take a while to heat, but the voltage drop across it may be sufficient to cause a very small and low energy spark. Very little energy would be needed to ignite a stoichiometric hydrogen/oxygen mixture.

If you have not thrown the remains of the battery away, you might investigate the condition of the inter-cell dividers. If some of them are bent one way and the rest are bent the other, this would suggest that the explosion occurred in only one cell. Close examination of the lead straps and joints in that cell may give you the explanation you are seeking.

--
~ Adrian Tuddenham ~
(Remove the ".invalid"s and add ".co.uk" to reply)
www.poppyrecords.co.uk

It is *not* a base. It is a buffer.

Correct (for once). It is a *buffer*, not a base. No matter how concentrated it will not result in a PH < 7. Well, some screwy things happen in pool chemistry, but organics are a lot more complicated.

(...)

6,000 (Six thousand) degrees C.

I expect that would be sufficiently hot.

--Winston

I've reduced the photo's file sizes and add another photo related to the venting of the battery. See ftp://ftp.meraka.csir.co.za/pub/in/Battery_Explode/

The battery does not vent through the filler caps but through a vent on the side. There seems to be a vent channel that runs through the top of the battery and interconnects all 6 cells. It exits through a single vent on the right hand (positive pole) side of the battery through a 90 degree elbow. There battery design caters for the elbow to be mounted on either side of the battery The vent hole on the negative pole side of the battery is sealed and there is no vent elbow. The vent elbow was blown off by the explosion. I picked it up from the floor and drop on top of the battery for the photograph. It has been slightly dosed with baking soda while nutralising the acid on the floor.

The vent elbow wasn't blocked after the explosion :-).

In this type of battery vent design any gas generated in one cell could spread to all cells. A hot spot in any of the cells could therefore ignite the gas. I am of the opinion that interconnecting the vents between cells could increase the chances of an explosion.

This type of venting does have its benefits. It also prevents acid residue forming on top of the battery and helps to keep acid from collecting on the battery poles. A small pipe is often connected to the elbow to channel acid droplets to below the cassis level. It prevent ingress of dirt and other stuff from the top surface of the battery (the cell caps have no vent holes). I have seen car batteries been cleaned using pressure sprays at the car wash.

I haven't cleaned the top of the battery before I took the photos and it provides some proof that this venting design keeps the battery top free of acid residue.

I could not determine where the battery was manufactured. We have, or use to have a local Willard factory, but I doubt their capacity to manufacture all the Willard battery models.

Many thanks for all the feedback on the possible causes of the explosion. There seems to be a couple of possible scenarios that might result in the rapid disassembly of a lead acid batteries when connected to a high current load.

Gerhard van den Berg

It is clear you do not appear to quite understand the concept of weak acid. Washing ammonia is also a weak acid.

True so far. And a property that earned it the nickname "washing soda".

Well, make that strong acid as well as strong base.

And in solution by itself, it is not neutral but lowers pH.

This is total gibberish. The pH of aqueous sodium bicarbonate is around

8.3 and it doesn't dissolve particularly well in water.

Sodium bicarbonate is well known as the mildest of the sodium alkalis which makes it useful for mopping up acid spills. It is used in cooking.

No. It is *very* clear that you do not understand this stuff at all.

What do you mean by washing ammonia? Aqueous solutions of ammonia are strongly alkaline. Not quite as potent as caustic soda but still strong.

Ammonia can technically behave as a weak acid in some circumstances but that is not helpful in this discussion.

Wrong again. Sodium bicarbonate (sodium hydrogen carbonate in modern parlance) is *BAKING* soda. It is normally a very weak base.

Washing soda is (di)sodium carbonate and a lot more soluble in water and a moderate alkali at about pH 11.6 in water. The surface of washing soda crystals is inclined to react with atmospheric CO2 in moist conditions and form a layer of the less soluble sodium bicarbonate.

And finally sodium hydroxide is a vicious alkali with pH around 14.

Absolutely clueless does not do justice to your claimed knowledge.

It isn't so effective on strong alkalis and caustic. But in large amounts it will help soak up any spills and bring the pH away from the dangerously corrosive to skin levels. It is useful for this purpose in labs - you can't do much harm with it on most chemical spills.

Total rubbish. What planet are you on? What have you been smoking? Aqueous sodium bicarbonate 0.1M is pH 8.3 see for example its MSDS

Regards, Martin Brown

Are you saying that sodium bicarbonate mixed with an equal quantity of sulfuric acid solution will *not* result in a solution of higher alkalinity than the original sulfuric acid solution?

How can that be? Your later reply supports the contention that the resulting solution *will* be more neutral.

Yes, I agree. Good catch.

When combined with a base, yes.

More to the point, when mixed, it will tend to *increase* the alkalinity of a strong acid; tending to neutralize it as well, correct?

--Winston

(Corrected chemical information)

Thanks for the information, Martin.

I readily admit to severe retardation WRT chemistry. I just assumed that mixing in sodium bicarbonate would tend to make a sulfuric acid solution less acidic and tend to neutralize it, for better or for worse.

This was a lot more controversial than I thought it would be.

--Winston

--
Apparently, you do, since you accused me of making a misleading
statement, which I didn't, and now you're trying to brush off the
responsibility for the accusation.

--
Oops...

should read ... "innocuous sodium sulfate."