Talk:Photoflash battery

AA
Were there really AA photoflash batteries? The idea of photoflash batteries was high current and short life, different from most other uses. But AA sort of by definition has lower current. All the flash units I ever had were (and still are) BC, which means battery and capacitor. A low current, higher voltage battery charges a capacitor, which then supplies the high current pulse. But for simpler cameras, and in earlier years, it was just two photoflash batteries. But now alkaline batteries can easily supply the current needed, and have a long shelf life, besides, so no need for photoflash batteries. Gah4 (talk) 09:51, 25 October 2018 (UTC)


 * Wouldn't AA photoflash batteries have been used in the "brownie" style of compact camera? Perhaps some ancient copies of Popular Science are on line that talk about photoflash batteries...must browse Google Books for this. --Wtshymanski (talk) 00:35, 30 October 2018 (UTC)


 * There are a lot of Brownies, some more compact than others. There is, for example Kodak Brownie Hawkeye, one has a flash in the picture.  I think at the time of the instamatics, they went to Alkaline, either AAA or PX825, and it might be that flashcubes take less current.  I have some #40 flashbulbs, which I believe are designed for 120V, but may work on less:  See: flashbulb technical data.  More usual sized, AG-1, M3, #5, and similar, I know say use 3 volts of more. Best is a battery-capacitor flash unit with a 15V or 22.5V battery.  I don't think I ever used a non-BC flash unit.  Confusingly, the batteries used with BC units might also be called photoflash batteries, but they don't supply the high current like C and D cells. Gah4 (talk) 01:27, 30 October 2018 (UTC)


 * Batteries manufactured for photoflash purposes were typically relatively high voltage and low current. Often a 15 or 22.5 volt battery, the latter of the same size as that used for the Regency TR-1 radio (it was the radio that used the photoflash battery not the other way round). As noted above, it was used to charge a capacitor which then provided the high current pulse to fire what was (at the time) a relatively large flash bulb (The no. 1, the same size as an Edison screw light bulb, down to the smaller PF-1). The batteries are still manufactured but not for photoflash purposes. A picture of the 22.5 volt version can be found here.


 * The introduction of zinc-chloride and particularly alkaline batteries coupled with smaller flash bulbs (the AG-1 size), permitted the use of AA size batteries to fire the flash bulb directly. This, more or less, coincided with the release of the 'Instamatic' camera from Kodak taking the cartridge 126 film. The batteries usually also powered the metering circuits of the camera, if present.


 * A bit of research shows that there are no AA size batteries sold specifically as 'photoflash' batteries for flash bulbs, either historically or now. However there are AA size batteries using Nickel-Metal Hydride rechargeable technology (See here), but even these are not sold specifically as photoflash batteries but merely as 'ideal for photoflash', a claim that would apply to any Ni-MH battery. But in any case these seem more marketed for electronic flash units. A number of battery sizes are marketed as 'photoflash' but these turn out to be regular camera batteries for either (semi-)automatic film cameras or digital cameras or high voltage (>300 volts) batteries to directly power an electronic flash unit.


 * Thus, this article is a total nonsense. DocFergus (talk) 17:59, 30 October 2018 (UTC)


 * I have to declare that the source used for this article is unreliable. That he discusses non existent photoflash batteries is a worry. That he fails to understand the basic physics and chemistry behind batteries is a bigger worry. He considers manganese dioxide as the cathode in the zinc-carbon battery (the clue really is in the name). Manganese dioxide is a non-conductor of electricity and by definition cannot be an electrode (and the linked article correctly states as much). Adding powdered carbon does not make the manganese dioxide conduct as he claims. It is the carbon that conducts. It seems that he, like most people, always wants the cathode to be part of the current producing reaction. In primary cells, the cathode almost always is resolutely not part of the reaction but is merely an electrode that allows the electrons to return to the cell (though choice of material does influence the cell E.M.F.). DocFergus (talk) 12:07, 31 October 2018 (UTC)


 * Well, the chemistry is pretty strange, but it is the same as Zinc–carbon_battery, where reduction of manganese dioxide is the cathodic half reaction, and oxidation of zinc the anodic half reaction. In most cells, both electrodes are metallic, but not in this one. To me, it is the manganese dioxide that is the cathode, and the carbon helps electrons get to it, but then again, the carbon is the cathodic terminal.  In any case, it is the same chemistry of zinc-carbon but different ratios of constituents to allow for high peak current. Since the carbon doesn't enter into any chemical reaction, I have a hard time calling it a cathode.  Gah4 (talk) 13:39, 31 October 2018 (UTC)


 * No, the chemistry isn't strange at all. It's just that most folks don't fully understand it (or probably more accurately: think they do but do not). There are different and unconnected reactions going on and they try to roll it all into one. To simplify matters (though this is not the fully simplified case as we shall see) consider a zinc-carbon battery with ammonium chloride only as the electrolyte. First, as I said before manganese dioxide cannot be an electrode or the cathode because it is a non conductor and fails the requirement by definition (it is also insoluble so it could not take part even if it wanted to). Adding carbon powder to it does not change that fundamental point - the carbon conducts, the manganese dioxide resolutely cannot. The purpose of the battery is to provide an electric current. The manganese dioxide can be removed from the battery without affecting its ability to produce that current precisely because it plays no part. The true current producing half reactions are.


 * Anode: Zn → Zn2+ + 2e−


 * Cathode: 2 NH4Cl + Zn2+ + 2 e− → ZnCl2 + 2 NH3 + H2


 * Overall: Zn + 2 NH4Cl → ZnCl2 + 2 NH3 + H2


 * The carbon cathode takes no part in the reaction other than to allow the electrons conducted out of the cell at the anode to return to it. Indeed a cell made from a zinc anode, a carbon cathode and ammonium chloride solution in water will produce an E.M.F. and current without any assistance from manganese dioxide.


 * There are two products of the reaction that introduce problems. The first, and visibly obvious is the production of hydrogen gas which appears as bubbles on the cathode and restricts its ability to return the electrons to the cell. This is called polarisation. The sole purpose of the manganese dioxide is to solve this problem and acts as a depolariser. Because it is a powerful oxidiser, it oxidises the hydrogen into water with the following unrelated reaction.


 * 2 MnO2 + 4 H → 2 H2O + Mn2O3 (The single H because the manganese dioxide reacts with the hydrogen atom the moment it is released)


 * The second product is the ammonia molecule released in the cathodic half reaction. Ordinarily it would react with the water to produce ammonium hydroxide. But: there is an inviolable rule in chemistry that if an insoluble compound gets a chance to form, it is formed. Thus the ammonia reacts with the zinc chloride produced to form the insoluble ammoniacal zinc chloride with the following also unrelated reaction.


 * 2 NH4 + ZnCl2 → Zn(NH3)2Cl2 + 2 H (These H atoms being oxidised by the manganese dioxide as before)


 * The ammoniacal zinc chloride, being an insoluble non conductor, raises the internal resistance of the cell as the discharge proceeds limiting its ability to produce current. This applies to the wet or dry cells because the ammoniacal zinc chloride is produced at the cathode (i.e. inside the porous pot).


 * Most folks try to show the all the reactions together as the current producing reaction, but it is strictly wrong to do so. Where zinc chloride is used in part or completely as the electrolyte, a similar reaction occurs but in this case there is no ammonia released and no ammoniacal zinc chloride produced, which is why this variation has an apparently longer life. The theoretical Ah capacity is similar but the internal resistance is not reduced as quickly.


 * If potassium hydroxide is substituted (producing an alkaline battery), the situation complicates itself slightly because although the potassium hydroxide electrolyte does take part in the half reactions, overall it is not consumed. Once again: the manganese dioxide can be removed without affecting the current producing reaction. The current producing half reactions are:


 * Anode: Zn + 2 KOH → ZnO + H2O + 2 K+ + 2 e-


 * Cathode: 2 H2O + 2 K+ + 2 e- → 2 KOH + H2


 * Overall: Zn + H2O → ZnO + H2


 * The polarising hydrogen produced at the cathode is separately oxidised by the manganese dioxide exactly as before. It is the potassium hydroxide not being consumed that is responsible for this cell's longer life (and nothing else). The electrolyte is not diluted as the active chemical is not consumed but instead, as the discharge proceeds, the electrolyte actually becomes more concentrated as the water is consumed. DocFergus (talk) 18:26, 31 October 2018 (UTC)


 * Taking that much explanation to me makes it pretty strange. Many cells can be explained by one half reaction at the anode, and one at the cathode, and you are done. As you say, the manganese dioxide can be removed without affecting the current producing reaction, but to keep the cell producing current, you need to keep the equilibrium going in the right direction. I suppose in a wet cell, you can let the hydrogen bubble out of the cell, though bubbles on the electrode will still have some effect. Depolarizing is still important in the long term for the cell.  To get back to the subject, for photoflash cells short pulses of high current are needed, and so depolarization can occur later.  Besides flashbulbs, I remember such cells also being used for model rocketry, which uses a nichrome wire to ignite the engine with much more current than a flashbulb.  Since I didn't have those, I could only use my rockets where I could get the car nearby, and use its battery. I think there also used to be cells optimized for low current drain, but longer life.  Hard to find now. And thanks for the more detailed explanation. Gah4 (talk) 21:02, 31 October 2018 (UTC)


 * Also reminds me, when I was young, I used to do some electrolysis experiments, such as with salt water making hydrogen and chlorine. My favorite anode was the carbon rod from a zinc-carbon D cell, which is pretty easy to get out. I remember also trying to electroplate magnesium from epsom salt solutions, but (obviously) that never worked. Gah4 (talk) 21:02, 31 October 2018 (UTC)

This varies greatly from my local battery reference, "Handbook of Batteries Third Edition" edited by by David Linden and Thomas Reddy. In Chapter 8 they describe the reactions as requiring the manganese dioxide. The battery won't work without it, the amount and composition of the MnO2 is critical to performance of the battery. --Wtshymanski (talk) 20:56, 31 October 2018 (UTC)


 * They are wrong. That is what makes it an unreliable source. They do not understand either the physics or the chemistry (and they are far from alone). Manganese dioxide as a non conductor cannot be an electrode because, it is an insoluble compound and cannot dissociate into ion radicals. Even the first sentence of the article at electrode, says, "An electrode is an electrical conductor used to make contact with …" (my emphasis).


 * I have no idea what your background is but if you did physics at school, you would almost certainly have made a simple cell (or had one demonstrated). But if you did not then try it for yourself. Put a zinc and carbon electrode into a solution of ammonium chloride (or potassium hydroxide) and measure the voltage produced. It will be around 1.4 volts (1.5 volts for KOH). The manganese dioxide's sole purpose is to oxidise the hydrogen produced as current is drawn and it is essential for this purpose alone as hydrogen gas will quickly throttle the current flow. The purity of the manganese dioxide affects its ability to oxidise the hydrogen quickly enough as current draw rises. The amount is to ensure there is enough that it is not consumed before the other active materials. DocFergus (talk) 08:28, 1 November 2018 (UTC)


 * Since the above post, I have been looking through a number of text books on the subject published from recently back to the 1930's. Over the course of this time there has been a change in which the subject matter is presented (not unsurprisingly). From the 1930's up to 1970's, there is consistency in that the books discuss the basic electrochemical cell (i.e. without a depolariser) and the reactions involved. They then follow it up with the development of adding the depolariser (describing a few depolarised cells). When they discuss the dry-cell, they (almost) consistently separate out the electrochemical reaction and (correctly) discuss the role of the manganese dioxide as a separate depolarising reaction. I do note that they do combine the electrochemical reaction and the reaction that produces the ammoniacal zinc chloride, but I can forgive that because that reaction occurs anyway so could legitimately be considered valid.


 * However after the 1970's, there is a trend of no longer discussing the basics of electrochemical cells and presenting the dry-cell as the sole example, rolling the entire reaction process into one equation. None of the works that I looked at claimed that the manganese dioxide was the cathode or claimed that it was essential to the electrochemical reaction.


 * More recently, the works introduce the alkaline battery into the mix and having noted that the potassium hydroxide does not take part in the reaction presents slightly different half reactions (rolling in the depolarising reaction) to give


 * Anode: Znundefined + 2OH−undefined → ZnOundefined + H2O + 2e−
 * Cathode: 2MnO2undefined + H2O + 2e− → Mn2O3undefined + 2OH−undefined


 * Now there is a problem with these equations. In the anode half reaction two OH- appear out of nowhere (with no explanation of where the corresponding + has gone), and in the cathode reaction two OH- are produced and remain unaccounted for as OH cannot exist in its own right (and particualry, the corresponding + still remains unaccounted for). Having stated that the potassium hydroxide does not take part, they are reluctant to include it and confuse the issue. The reality is, as I stated above, that the claim that the potassium hydroxide does not take part is incorrect. The OH comes from the potassium hydroxide leaving a K+. This K+ then recombines with the OH produced at the cathode. The upshot: that although the potassium hydroxide is involved in the reaction, the quantity of it remains unchanged (which may be why some think it does not take part). DocFergus (talk) 12:29, 1 November 2018 (UTC)

You are barking up the right tree. However your hypothesis that '... depolarisation can occur later' does not work. Although manganese dioxide is described as a powerful oxidiser, it is also a pretty lazy oxidiser in some circumstances. Manganese dioxide will not, by itself, oxidise hydrogen gas molecules (H2) to produce water. It will only oxidise the hydrogen atoms (nascent hydrogen) as they are produced, but before they can pair off.

As you note: in a wet non-depolarised cell, if enough hydrogen is produced it should escape the cell. However, enough of it clings to the cathode to lower the current sufficiently that that does not really happen. Of course, if you give the cell a sharp knock, the gas can be dislodged - at least temporarily.

You have mentioned 'photoflash' batteries again, but so far there is no evidence presented that such specialist batteries ever existed beyond the 15 or 22.5 volt (very) low current batteries for charging a capacitor and, as I have previously posted above, I can still find no evidence of their existence. If they existed it should be easy to find an on-line reference to them but there is nothing.

Then Kodak instamatic appeared in the mid 1960's (which did not use a capacitor to fire the flash bulb) and flash bulbs were still in use up to at least 1990 (now in the form of flash bars with multiple flash bulbs), so that is at least three and a half decades during which such batteries might have been produced. But there is nothing anywhere that I can find. DocFergus (talk) 12:29, 1 November 2018 (UTC)


 * Lead sulfate isn't a conductor, either, and yet is undisputedly (?) part of the reaction in a lead-acid battery. Some authoritative citations would clarify this for all of us. --Wtshymanski (talk) 18:20, 1 November 2018 (UTC)


 * This one explains that Kodak had Mallory make alkaline AAA cells for their cameras, which eventually included instamatics. Some instamatics used PX825, and alkaline button cell, but larger than most.  (and hard to find today.).  I suspect that new ordinary C and D cells would work fine, but less new wouldn't supply enough current, fast enough.  It is supposed to be timed to peak while the shutter is open, so a variable delay isn't good. The 15V and 22.5V batteries for BC flash units are also called photoflash batteries, though they are for low current use.  I suspect also that AG-1 and flashcubes need less current than the larger M3 and #25 bulbs, or even the earlier household lamp sized flashbulbs.  (The latter have ordinary lamp screw bases, and I believe could be powered by 120VAC.).  All the flash units I ever owned were (and still are, as I still have some) BC type.  But I do remember the C and D photoflash batteries.  One that they were used for is model rocket igniters, which take much more current than flashbulbs.  But big lantern batteries were a good choice for them.  More recent rocket igniters use smaller nichrome wire with something on them to help start the engine, and are powered by four AA alkaline cells (through way too small wire).  Gah4 (talk) 18:36, 1 November 2018 (UTC)


 * Here is the Estes Rocket Catalog which on page 91 shows a size D photoflash battery and claims 16A short circuit current when new. They have launchers that use between four and eight of them. Gah4 (talk) 18:48, 1 November 2018 (UTC)


 * The Mallory battery that that you pointed to is a 15 volt low current battery. It was never designed for and would be incapable of firing a flash bulb directly. You had to use it to charge a capacitor first.


 * It is interesting that the battery in the catalogue that you linked to is made by Ray-O-Vac. Ray-O-Vac was the only battery company that I am aware of that produced specialist zinc-carbon batteries for just about any application with their catalogues full of marketing bullshit about how their specialist batteries were better at what they were specifically marketed for than anyone else's (though I don't believe that the 'photoflash' range was ever marketed here). Ray-O-Vac batteries appeared in the UK somewhere around 1968 but disappeared less than two years later when the importers were prosecuted under our Trade Descriptions Act (in fact a later boss of mine was the 'expert witness' which is how I got to know about it). It transpired that like most other battery manufacturers, Ray-O-Vac only produced two types of battery. The regular zinc-carbon battery with ammonium chloride and zinc chloride mix and the 'high power' battery using only zinc chloride. Every specialist battery was simply one of these two types with a different outer casing and a higher price tag (often up to double).


 * Your catalogue claiming that the battery supplies up to 16 Amps under short circuit does not describe any type of specialist battery. Any zinc chloride 'D' size battery should easily be able to manage 16 Amps. I have just checked a box of unused 'D' size zinc chloride (took a bit of finding in our stores) and easily got an initial short circuit current of 19.5 Amps (you have to connect a few in series to overcome the burden resistance of the ammeter). And I just noticed the 'best before' date is March 2016.


 * A lead-acid battery is not a primary battery. Secondary batteries are a whole different electrochemistry (one essential difference is that unlike primary cells, the cathode (discharge case) does take part in the electrochemical reaction). The structure of the lead sulphate that forms during discharge is not strictly insoluble but is (sort of) semi-soluble in the dilute acid electrolyte (the form is 'spongy lead sulphate'). If allowed to remain in any partially discharged cell, it reforms itself into a truly insoluble lead sulphate structure from which it is impossible to take any further part in the cell's operation because being truly insoluble cannot dissociate into ions. Something similar applies to the lead dioxide but, unlike the lead sulphate, does not change form with lack of use.


 * This is the simple (and, admittedly, not entirely satisfactory) version. If want the more complete story, please indicate that here. I will, however, post it to your talk page as we really are well off on a tangent here. DocFergus (talk) 15:59, 2 November 2018 (UTC)


 * I take your point about Linden supporting the points in the article but we are still lacking evidence of any such batteries existing (which if they don't still makes Linden unreliable because he is describing the non existent (not related to batteryuniversity.com is he!?). DocFergus (talk) 16:18, 2 November 2018 (UTC)


 * I mostly try to buy alkaline, especially if they are on sale, but otherwise the only ones I see are 'heavy duty'. No-one wants to sell less capable ones now.  I also specifically remember Ray-O-Vac, as many battery companies guarantee to repair or replace your device damaged by their leaky battery.  At least twice I have had something damaged and sent it to them.  They nicely replaced my Fluke DVM, even with a newer model, though it took a while.  I believe that was alkaline, too, which seem usually less susceptible to leaks, but sometimes they still do.   Yes the 15V and 22.5V are designed for, and one hopes optimized for, BC flash units.  They do last amazingly long in such units even when not used, but I believe that they are marked as photoflash as they have no other common use, or at least did in years past.  I have a neat little BC flash unit, Agfalux C, that used to use a mercury battery, but now I can get a two cell lithium battery for it. Much fun to use with older film cameras, though I still haven't used it since I got that battery for it. I also remember transistor batteries, presumably designed for low current for a longer time, but maybe as you note, just the same inside.  Gah4 (talk) 20:16, 2 November 2018 (UTC)


 * Do not alter other people's posts in the way that you did. The indenting was exactly as I intended. Your alteration makes it look as though my reply to was being made to you.


 * Many battery companies offered a replacement for your device if one of their batteries leaked. They were, more or less, forced to as one company offered to do so as a way of selling their batteries. I believe, but could be wrong, that Duracell was the first to do so. I do not believe any battery company does anymore (but again, as ever, I could be wrong).


 * Zinc-chloride and zinc-carbon batteries are still made and still available but only from a small handful of battery manufacturers (mostly Chinese, many of which label and sell them as alkaline). I know GP still make them (largely as OEM batteries for supply with other products). A couple of years ago, I bought two smoke alarms. In spite of the instructions stating that only alkaline or lithium batteries should be used, they were nevertheless supplied with standard GP 6F22 zinc-carbon batteries (with expiry dates about two months later).


 * So called transistor batteries, as you surmised, were standard zinc-carbon batteries but constructed as layer cells rather than cylindrical. DocFergus (talk) 12:09, 3 November 2018 (UTC)


 * The problem with the indenting is that I couldn't figure out how much to indent mine. (I believe fixing indenting is allowed, but I haven't looked recently.).  If you want to do unusual indenting, sign at the end of each one, so we can separately reply to them. Otherwise, sorry about that. Gah4 (talk) 04:27, 4 November 2018 (UTC)
 * Indenting is a PITA and is why long discussions shouldn't happen on talk pages. Linden doesn't claim any size of photoflash battery was ever made; the reference only says that a photoflash chemistry with a 1:1 carbon/MnO2 mix was made for flashes. Chapter 8 of Linden's book discusses at length the non-conductivity of MnO2 and how that affects the design of dry cells.  Lead sulphate isn't conductive either - and we can't arm-wave that away. I also found the simplified overall reaction listed in "Standard Handbook for Electrical Engineers" showing zinc and manganese dioxide reacting to form zinc oxide and Mn2O3. I'm not a chemist, if two different McGraw Hill books give me the same chemistry who am I to dispute them?  Could we get a reference that says we can make a carbon-zinc battery without MnO2 ? --Wtshymanski (talk) 04:57, 4 November 2018 (UTC)


 * You could put a vacuum pump on to suck the hydrogen out. Gah4 (talk) 06:28, 4 November 2018 (UTC)


 * I'm not sure that it would work on a dry type battery. Plus you have to consider the power required to power the pump. DocFergus (talk) 14:53, 4 November 2018 (UTC)


 * I have known people to use batteries even when AC power was available, for the low noise. It was slightly supposed to be a joke, as I don't know the diffusion rate, but if there is a gradient it will eventually diffuse out. And yes, it might work better in the wet cell form. Gah4 (talk) 06:17, 5 November 2018 (UTC)


 * My point was and still is that Linden seems to be discussing that which does not seem to exist. Which begs the question: from where did he get the information?


 * As I said above almost any pre 1970 text on the subject discusses non-depolarised cells (and is where from which I got the equations at the top of my third post). Volta's original pile was just such a cell. Sodium Chloride solution with copper and zinc electrodes and no depolariser. It gave him about a volt per cell though precious little current before it polarised. You can substitute ammonium chloride for the salt without any problem. And substitute carbon for the copper which raises the E.M.F. to about 1.4 volts per cell. Still no Manganese dioxide. It still won't deliver much current, but the addition of MnO2 around the cathode fixes that.


 * As for that lead sulphate. Discussed on your talk page as promised as it is too much of a tangent for here. If anyone else is interested then it is thataway. DocFergus (talk) 14:53, 4 November 2018 (UTC)


 * Mercuric oxide is non-conductive as well, and was widely used in mercury batteries.--Wtshymanski (talk) 23:35, 6 November 2018 (UTC)


 * Interestingly, Indium_tin_oxide is both conducting and transparent, and even more, can be easily formed into thin films on surfaces. Gah4 (talk) 23:47, 6 November 2018 (UTC)


 * And the relevance to batteries is …? DocFergus (talk) 14:48, 7 November 2018 (UTC)


 * Relevant to the discussion on conducting oxides. I don't know of its use in batteries. I suspect that there are more conducting oxides, but that aren't transparent. Gah4 (talk) 15:28, 7 November 2018 (UTC)


 * Mercuric oxide is non conductive in its own right and insoluble in water and consequently non conductive in water. It is sufficiently soluble in sodium hydroxide or potassium hydroxide (mercury batteries used either with different results) that it dissociates and becomes conductive . Although soluble, the potential gradient between the cathode and the electrolyte keeps it from reacting unless a current flows (the same mechanism stops the lead dioxide from reacting with the acid in a lead-acid battery when no current is drawn). Mercury batteries are another chemistry where the electrolyte's active ingredient is usually omitted form the half reactions but OH- radicals appear out of nowhere. As with the alkaline battery, in reality, the NaOH or KOH does take part in the reaction but the amount produced at the cathode equals the amount consumed at the anode.


 * Because the cathode is mercuric oxide, it conveniently doubles up as the depolariser so that no separate depolariser is required. A little carbon is added as well to decrease the cell's internal resistance as well as to discourage the evolved mercury from forming droplets large enough to short circuit the cell. The carbon is usually in the form of graphite as purity is not important as it plays no part in the reaction but is something that the mercury can 'stick' to. Adding manganese dioxide to the cathode increases the cell voltage from 1.35 to 1.4 volts but with a greater voltage fall off as discharge proceeds (these were usually sold as hearing aid batteries). DocFergus (talk) 14:48, 7 November 2018 (UTC)


 * For ones that ionize, like NaOH and KOH, I wouldn't consider the cation part of the reaction, but is there to keep the pH appropriate, so that there are enough OH- around. Gah4 (talk) 15:28, 7 November 2018 (UTC)


 * I was always taught that reaction equations should be complete. Further when a negative ion or electron is produced, the equation should show where the corresponding positive ion is in order that the equation is balanced. DocFergus (talk) 16:31, 7 November 2018 (UTC)


 * I was looking up something else, and found this indicating the chemistry of alkaline cells. Note again the zinc and manganese dioxide, with the cathode specifically being described as manganese dioxide. They may not be a WP:RS, but they should know the chemistry. Gah4 (talk) 05:44, 11 February 2019 (UTC)

AA (continued)
See this link : https://www.flickr.com/photos/48441030@N00/2124400146 (Yes -- See PHOTO in Link: https://www.flickr.com/photos/48441030@N00/2124400146.  If there were AA then there were also size C.  Do an image search via google please!!!)

(The above is from User:Klimot. I don't know how to make an actual signed post for it.)


 * Encouraging, but we need a valid citation. Anyone can put any kind of Photoshopped image on Flickr. --Wtshymanski (talk) 19:34, 5 December 2018 (UTC)

Eveready 497 Battery
The Eveready 497 Battery had a voltage of 510 volts. It also had a tap at 180 volts. If you do image searches, you should be able to see an example of this. (Here is a link, not sure how long this will last: https://www.ebay.com/itm/VTG-EVEREADY-NINE-LIVES-PHOTOGRAPHIC-FLASH-BATTERY-497-510-VT-LEATHER-CASE/201911969737?hash=item2f02e427c9:g:YO4AAOSwtGlZBikZ:rk:2:pf:0   ) -klimot


 * Also, I suspect that eBay is not a WP:RS. Gah4 (talk) 01:07, 24 January 2019 (UTC).


 * Yes, but a photo of the actual item in question is - the photo of it just happens to be on Ebay. In many cases, those photo's only last until the item is no longer for sale. Many disputes here can be resolved by doing image searches of items that were actually made.  Not sure why the photographs of actual items cannot count as an expert source. 29 January 2019 - klimot


 * Wikipedia has funny rules on sources. Not so obvious, secondary sources are preferred over primary sources. Reminds me, in a book on famous (or maybe not so famous) computer scientists, there was mention of a case where the primary source was wrong. As is often the case, it was written for a conference paper sometime ahead. Between submission and publication, it was found to be wrong. Secondary sources included the fix. Primary sources are on the cutting edge of science, often before things are understood as well as they should be. Gah4 (talk) 05:51, 11 February 2019 (UTC)