Talk:Battery room

Seawater + battery acid =
Since several editors seem confused about this, I'm leaving a note here. Hydrogen_chloride states (with reference!) that sodium chloride + sulfuric acid = hydrogen chloride (definitely not chlorine); but that even this reaction only works with dry reagents. Since seawater is over 95% water, and battery acid is usually over 50% water, it is highly improbable that contamination of battery acid with seawater will produce appreciable amounts of hydrogen chloride gas. (There is a slight chance it would produce hydrochloric acid and/or sodium sulfate, or simply dilute the acid, any of which could be highly damaging to the battery, but that's a completely different matter (and one that should be noted in the article, if a reference can be found).) Mysterious Whisper (SHOUT)  11:46, 18 September 2012 (UTC)
 * Ninety seconds with Google Books, or we could debate it for weeks. People who seem to know what they are talking about say "chlorine" and who are we to dispute with the submariners? --Wtshymanski (talk) 15:11, 18 September 2012 (UTC)
 * Hmm... yes. 'Cause you were the first one to provide a reference (any reference) to support your changes. Incidentally, I checked the reference, and touched up a few errors. Page 1 doesn't mention chlorine; page 2 does, but doesn't mention 'electrolyte' or 'acid', simply "contact of saltwater with the submarine's batteries". To me, that says electrolysis, but I'll stick with what the book says. Mysterious Whisper (SHOUT)  17:17, 18 September 2012 (UTC)


 * On the other hand, good rewrite (not the least because it cuts down on the unreferenced material) Mysterious Whisper (SHOUT)  17:17, 18 September 2012 (UTC)


 * I have spent far to many dull days aboard Royal Navy diesel-electric submarines. The danger is sea water coming into contact with the sulphuric acid electrolyte of the lead-acid batteries.  Chlorine gas is evolved.  The reaction is purely a chemical one - no electricity involved.  DieSwartzPunkt (talk) 16:31, 19 September 2012 (UTC)


 * My last statement: "...but I'll stick with what the book says." I quote the reference: "Chlorine gas could also be produced from the contact of saltwater with the submarine's batteries." Notice how my alteration to the statement in the article does not state whether it's a chemical reaction or electrolysis (or anything else); that's because the reference does not state whether it's a chemical reaction or electrolysis (or anything else). If you insist on changing the passage in the article, you'll have to find a reference that supports that change. Oh, and why did you delink the referenced work, and revert the page number? Mysterious Whisper (SHOUT)  16:56, 19 September 2012 (UTC)


 * Deletion of your reference was unintentional. Apologies.  However, you are suggesting that toxic gases are produced when sea water comes into contact with the battery - any part of the battery including its case?.  This is not the case, it is specifically the electrolyte.  The reaction is between dilute sodium chloride and dilute sulphuric acid = chlorine and a whole lot of other stuff.  As noted concentrated sulphuric acid on dry sodium chloride produces hydrogen chloride.  It's the water that changes it.  Almost any high school chemistry text book will have these chemical reactions in. DieSwartzPunkt (talk) 17:36, 19 September 2012 (UTC)


 * It's not my reference, and you didn't delete it (you just reverted it to a clearly inferior version). I'm not discussing chemistry anymore, I just don't want the statement in the article to declare anything the reference does not. If the reference said something like: "saltwater getting inside the submarine's batteries" we wouldn't be having this conversation. But it doesn't; it's dreadfully ambiguous. And without a better source, so must the sentence in the article be. Of course, it seems like the important thing to note is batteries + seawater = chlorine gas, which both versions communicate, so I don't understand what is so problematic about not mentioning acid. Mysterious Whisper (SHOUT)  18:01, 19 September 2012 (UTC)

 Hey, did you know if you type "submarine seawater battery acid" into Google Books, you can get literally *scores* of references? You should try it. True, it's not as much fun as edit warring to the death about trivia. Now we can stop waving them about and tuck them back into our pants. --Wtshymanski (talk) 21:53, 19 September 2012 (UTC)


 * No, but it's a good thing you knew that, because (as I'm sure you know) the burden is on you to reference the information you want to keep. One problem, though. Once again, I've checked the ref. Once again, it does not support what it's supposed to. Have you got the right page number? Page 319 doesn't seem to mention chlorine at all. Mysterious Whisper  (SHOUT)  23:08, 19 September 2012 (UTC)


 * If the reference fails to support the point then you should tag it with a tag, which appears thus .  Such material may then be treated as uncited.  However, as Wtshymanski points out there is no shortage of material that supports the claim (Such as this - 4th para.  Even Edison himself was aware of the danger .  A good book with a few examples: The list goes on.  If something is that much common knowledge there is no real need to cite it but as citations exist a plenty, why not? (See WP:CK and possibly WP:BLUE).  DieSwartzPunkt (talk) 12:24, 20 September 2012 (UTC)
 * Fixed the page number, page 361 (no idea why I got the page wrong, must have been another window I had open), which says in part "...The loss of many WWI boats was attributed in part to gas generated when battery acide poured out and mixed with seawater...." - yesterday Google Books let me see the whole page, now it's just a snipped but the significant line is there. --Wtshymanski (talk) 13:18, 20 September 2012 (UTC)

BATTERY ACID, SEAWATER, AND CHLORINE

There is much debate about what happens when "battery acid used in lead storage batteries is mixed with seawater." Some claim that chlorine gas (Cl2) is formed, others claim that hydrogen chloride gas (HCl) is formed, and others claim that neither gas is formed.

The confusion lies in the phraseology.

Let's differentiate between battery acid, which is approximately 35% sulfuric acid (H2SO4) and battery electrolyte, which is 35% H2SO4 in contact with the lead battery electrodes.

First, mixing battery acid with seawater, which contains about 3.5 % sodium chloride (NaCl), will not generate either chlorine gas or hydrogen chloride gas. A strong oxidizing agent is needed to convert chloride ion to chlorine, and it can be shown thermodynamically that sulfuric acid is too weak an oxidizing agent to do this.

Second, although dry NaCl in contact with concentrated sulfuric acid can produce hydrogen chloride gas under the right conditions, the conditions in dilute aqueous solution resulting from mixing seawater and sulfuric acid do not allow for the volatilization of the HCl. This means that attempts to explain chlorine-like physiological symptoms as being caused by gaseous HCl, rather than by chlorine, are incorrect.

Third, there are two ways that chlorine can be generated when it comes to batteries:

(1) If seawater gets between the terminals of any battery, chorine can be generated by electrolysis―a well known boating concern.

(2) If seawater gets into the cells of a lead storage battery, i.e., into the electrolyte, the lead dioxide in the electrodes, which is a strong oxidizing agent, can convert chloride ion to chlorine:

2Cl- + PbO2 +SO4 +4H+ =  Cl2 +PbSO4 + 2H2O

Fourth, lead dioxide is very insoluble in battery acid, so if electrolyte is poured out of a battery and is no longer in contact with the electrodes, there is too little PbO2 in solution to form any significant, noticeable amount of chlorine when mixed with seawater.

In conclusion, the statement that should be used when referring to the effects of seawater on batteries should be "Seawater contamination of the battery cells in lead storage batteries can produce chlorine." Expressions such as "mixing battery acid and seawater can produce chlorine" are misleading and fundamentally incorrect.

MANNY JA (talk) 01:19, 2 May 2015 (UTC)

Gasses evolved by overcharging batteries
It would be helpful to the project if Wtshymanski dod not edit on subjects that he does not know anything about. Something for which he has frequently been critisised.

First: as any high schoool student will tell you, the atmosphere is not 100% oxygen as you claimed (in the edit summary to this edit ). Second: overcharging batteries generate both hydrogen and oxygen gas. Since the hydrogen comes from the electrolysis of the water, where do you think the oxygen goes? For every litre of hydrogen produced, you also get $1/2$ a litre of oxygen. This oxygen is an extremely important part of the danger of explosion.

As hydrogen starts to be produced, there is little initial danger. The proportion of hydrogen evolved (assuming no oxygen for now) has to be within certain limits before its mixture with air becomes explosive (for hydrogen/air it is between 4.1 and 74.8% (v/v) hydrogen [Ref: any table of explosive limits - pick one, though most round to whole numbers]). So it would appear to be in a battery room. The proportion in the air has to be within the limits I have given before explosive combustion will occur. There is an obvious complication because hydrogen is lighter than air so the concentration at the top of the room will be higher than the concentration at the bottom.

The issue here: is that the evolved oxygen changes the lower limit quite considerably because the proportion of oxygen in the 'air' rises. In this case, the lower limit reduces to just 1.1% at the point where just enough hydrogen and oxygen have been produced. The upper limit is irrelevent in this context (even though it doesn't reduce by much) because you would have to have a serious overcharging problem to evolve that much hydrogen and oxygen. It doesn't take a genius to figure out that the size of the room relative to the batteries is irrelevant, other than that a larger room will obviously take longer to reach that explosive proportion. DieSwartzPunkt (talk) 17:08, 19 September 2012 (UTC)
 * For Jimbo's sake, don't tell my boss I know nothing, I'll never get to design a battery room again. They never have oxygen monitors. --Wtshymanski (talk) 21:53, 19 September 2012 (UTC)
 * I'm sure if your boss reads Wikipedia, he will figure it out for himself. I don't know how they do it in the US, but here we don't have oxygen monitors either.  There is no need.  What we do have to have is a hydrogen monitor.  They have to be set at 1% (v/v) minus the detector system uncertainty.  The 1% is determined by the lower explosive limit of the combined air, evolved hydrogen and evolved oxygen.  The stupid bit is that you have to have a hydrogen monitor even if the batteries are sealed maintenance free types.  The charging system for these should ensure that gases are never produced.
 * Since no attempt has been made to make this point in the article, the above is all rather academic. This is an encyclopedia.  Charging batteries give off both hydrogen and oxygen so why not say so?  If a cite is wanted for that point then I probably cannot dig up more than a few thousand.  Stating that the batteries give of oxygen as well as hydrogen does not invalidate the point being made in the article as it does not state what the problem magnitude of the LEL is.  If anything it makes the first part of the sentence more correct. I B Wright (talk) 14:46, 21 September 2012 (UTC)
 * Wow, too bad we don't have batteries that can store the energy that has been expended on this question. I can think of two reasons for not going into detail here:


 * 1) Wikipedia is not Wikihow. An encyclopedia is not for saying people should do a thing for some reason or another, though we say what they do a thing for some reason or another.
 * 2) This is the room article, not the battery article, so something like "Battery rooms are ventilated in order to avoid accumulation of hazardous gases" seems more appropriate than broaching the technicalities here of what is hazardous and why. Jim.henderson (talk) 23:05, 22 September 2012 (UTC)