Talk:Nickel–zinc battery/Archive 1

Dendrite problem?
I know that the classic problem with nickel-zinc batteries is the formation of zinc dendrites, which grow and eventually short out the battery. This should be addressed in the article.--Dwane E Anderson (talk) 12:27, 6 March 2009 (UTC)

Battery Life
Added a battery life section to address dendrites and cycle life. The battery cycle life of NiZn and NiMH are both similar. The number of cycles is dependent on temperature, charge/discharge regime, battery cell design (various cell designs may exist for the same cell chemistry), discharge current, and depth of discharge. Whatever number is specified it is important that the end-user of this information understands that both NiMH and NiZn when compared similarly have comparable cycle life specifications. —Preceding unsigned comment added by Sky1980 (talk • contribs) 17:07, 27 March 2009 (UTC)

Charging
The section on charging mentions "charge rates of C or C/2 are preferred." I do not think this is correct, but, in any case, the meaning of this statement should be clarified, and a citation added. Lovibond (talk) 03:22, 7 February 2010 (UTC)


 * Done - I've added a reference to PowerGenix's specsheet on NiZn AA cells confirming this. RanaChakra (talk) 07:44, 25 February 2010 (UTC)


 * The reference seems incorrect -- it refers to "C in amps". I was under the impression C, in this context, is charge, not current. If this is the case, the reference is indeed incorrect on this point and therefore unreliable. Is the symbol "C" used here for current or charge? Lovibond (talk) 00:53, 21 March 2010 (UTC)

Electrochemistry
This section is confusing. In one reaction we are talking about Zinc to its hydro-oxide. In another we are talking about Zn to its oxide. Aren't Zinc Oxide and Zinc Hydro-oxide two different compounds? —Preceding unsigned comment added by 123.201.38.103 (talk) 02:42, 10 April 2011 (UTC)

Damage from over-discharge / reverse discharge
My own personal experience with having lost several PowerGenix AA cells before figuring out what was going on: in multi-cell serial configurations, when one cell goes dead it can be reverse-charged by the other(s). This is certainly not beneficial for other cell types, but appears to quickly be fatal for NiZn - the cell no longer will hold a full charge, and rapidly deteriorates to the point the 'smart' charger will not restore it.

I'm not sure what sort of text or references would be appropriate to add to the main article, but here are a couple of links about the phenomenon:

http://www.candlepowerforums.com/vb/showthread.php?291828-Powergenix-NiZn-Poor-Performance http://www.candlepowerforums.com/vb/showthread.php?281051-Overdischarge-of-NiZn-Cells — Preceding unsigned comment added by Hizoomi (talk • contribs) 17:53, 5 March 2012 (UTC)

Dubious statement re. flash cycling speed
The section "Applications" contains the following statement; "Flash usually has a non-constant power, so a higher voltage means that a flash can be made ready to use faster."

I've marked this as "dubious" because it contradicts my experience with various flasguns over a period of nearly 40 years; I've found that using NiCd (and more recently NiMH) batteries invariably makes a flashgun cycle faster as compared to using alkalines in the same flashgun (typically 2 or 3 times as fast), despite the rechargeables producing a voltage of only 4.8v as compared to 6v. I suspect this is because rechargeables have a lower internal resistance (so I've heard) and hence presumably can make their power available more rapidly. -- 188.28.101.88 (talk) 18:59, 3 September 2012 (UTC)


 * I've now read a few other pages (mainly forum and blog posts), mainly from professional photographers who do a lot more photography than I do, and they all say that they use NiMH cells in flashguns rather than alkalines, for precisely the reason stated above, namely faster cycling. Those who have used NiZn cells report that they give faster cycling still, though how much of this is due to higher terminal voltage and how much due to low internal resistance is debatable, thus needing further research which is not the job of an encyclopedia. -- 188.28.101.88 (talk) 21:14, 3 September 2012 (UTC)


 * The inverter circuit in a typical flashgun requires quite a high current for it to operate in its intended manner. NiMH batteries are able to deliver the relatively high current required (several Amps in decent sized flashgun).  As you note, a primary alkaline battery has a much higher internal resistance and this limits the current that the invertor circuit can draw, in turn limiting the current it provides to the storage capacitor.  Hence, the flashgun takes longer to recycle with alkaline batteries than it does with MiMH.  Around 40 years ago, Sunpak made several flashguns that were able to be powered by Nickel Cadmium battery packs delivering the required 340 volts to recycle the storage capacitor directly.  The current availablility was much higher than that available from the inbuilt inverter circuit, and the result was a flashgun that recycled in under 200 miiliseconds!. 86.144.90.137 (talk) 12:36, 4 September 2012 (UTC)


 * You are not making the correct comparison here. The article is not about ordinary alkaline batteries.  I won't put the paragraph back, because it needs references, but I suspect that some of it might be true.    D b f i r s   10:40, 15 November 2012 (UTC)

What happens is that there is a voltage drop. Imagine any battery as an ideal battery with no internal resistance, with a resistor in series. If that resistor is large, it causes a large voltage drop. If small, a small drop. So when you draw a large current from the alkaline battery, you no longer have 1.5v. You have less, much less. But with the NiMH PR nizn batteries, the internal resistance is much less so your voltage won't sag as much (anonymous coward) — Preceding unsigned comment added by 172.56.39.108 (talk) 06:03, 2 September 2014 (UTC)

I have measured the internal impedence of these batteries and they tend to be as good as NiCd cells, which far exceed Alkaline for most of the alkaline discharge curve. I will have to say, given NiZn cells in good condition (which is the biggest problem with them in my opinion) - its low internal impedence and higher voltage will indeed allow flashes to charge faster - the combination of the two gives higher specific power (within same space constraints - we're not using a 200 cell pack to power a 2-AA photo flash) than Alkaline or even NiCd/NiMH. — Preceding unsigned comment added by 70.57.19.180 (talk) 15:35, 24 July 2013 (UTC)

Safe end-of-discharge voltage
I have seen lots of values (0V, 0.6V, 1V, the article currently states 1.3V) named by various people with complete conviction but never sourced. I would like to know where all those people take these values from, because right now it sounds like they were taken from their personal experience.B-2Admirer (talk) 11:44, 10 July 2015 (UTC)

Advantages Section: Health
The article simplifies zinc as "... not dangerous to health", which overlooks environmental quality: zinc is documented as a serious water-quality pollutant, widespread from industry and transportation corridors. — Preceding unsigned comment added by 76.21.7.83 (talk) 16:37, 19 August 2015 (UTC)

Disadvantages
The advantages section claims that these can be 100% discharged. The disadvantages section vlas they should never be fully discharged. This needs to be fixed whichever way it is. — Preceding unsigned comment added by 172.56.39.108 (talk) 05:57, 2 September 2014 (UTC)

I have found that the capacity of AA NiZn cells are currently rated at 1500mAh, lower than the typical 2000-2500 mAh for a NiMH AA cell. Due to the higher voltage, these have similar mWh capacity (something emphasized by PowerGenix repeatedly) compared to NiMH cells. However, the lower mAh capacity of the cells cause them to run low sooner than an equivalent NiMH AA cell. This might be seen as a disadvantage due to the shorter runtime, but the roughly equal mWh rating could balance this.

Any thoughts?

RanaChakra (talk) 07:32, 25 February 2010 (UTC)

The information in the book referred to by David Linden appears to contradict or differ from the figures at the top of this article and the Powergenix cell specifications. Compared to Lead Acid cells these cells have a higher specific energy, energy density and specific power. — Preceding unsigned comment added by Lkingscott (talk • contribs) 10:36, 3 March 2012 (UTC)

In 'Disadvantages', availability information is not correct. PowerGenix does not list AAA or SubC cells as available on their website (http://www.powergenix.com/?q=products). Honk Kong suppliers list SubC, AA, and AAA cells on ebay (http://www.ebay.com/itm/ws/eBayISAPI.dll?ViewItemNext&item=350564357529&pt=US_Rechargeable_Batteries&autorefresh=true#ht_3070wt_1002) and (http://www.ebay.com/itm/4-Sub-C-4500mWh-1-6V-Volt-NiZn-Rechargeable-Battery-Cell-Pack-With-Tab-Green-/150807598181?pt=US_Rechargeable_Batteries&hash=item231cd55465#ht_3348wt_1107).C0mpl1dyne (talk) 14:39, 24 May 2012 (UTC)

(Anonymous) I bought a bunch of these NiZn cells from PowerGenix. I've found they indeed have very low internal impedence and theoretically can supply a lot of current, but the faster they're discharged, reversal becomes a big problem. Because of the low mA*H rating these batteries should only be used in devices that truly require the higher voltage, or in devices that have switching power supplies that can reduce current drawn with higher voltage - and thus their mW*H number becomes important. And never wait till the batteries go dead before recharging them, that will reduce damage to them... It sounds like NiZn are more fragile than NiCd and NiMH. I suppose these facts of special attention needed for these batteries marks a huge disadvantage - thus the limited availibility and use of this technology. — Preceding unsigned comment added by 70.57.19.180 (talk) 15:10, 10 June 2012 (UTC)

Well, mAh is current, not power output, so is influenced by the voltage. As NiMH is 75% of the nominal output voltage of NiZn, isn't 1875 mAh for NiZn directly comparable to 2500 mAh for NiMH? — Preceding unsigned comment added by 176.249.62.114 (talk) 11:35, 25 August 2017 (UTC)

The first paragraph could totally be untrue. As many may notice, Alkaline batteries have a drop voltage as it being used and over time (let assume each have approximately 3000 mAh capacity) by discharging about just 15% of battery under a common load the voltage will decrease to about 1.3 which is close to NiMH or NiCd. It maybe better to notice it's a better replacement to Nickel oxyhydroxide batteries which have a higher voltage cell and it's being used in many digital cameras or high maintenance devices. — Preceding unsigned comment added by Known14 (talk • contribs) 17:55, 2 September 2018 (UTC)