Anyone still here still using NiZn AAs?

[wus]

I'm thinking of buying NiZn AAs to power an electric razor, but I'm reluctant because I find nearly no newer posts here on NiZn. I realize that the application windows for this sort of rechargeables is pretty small, but is it diminishing? Has there been any newer development which made NiZns obsolete?

Does anybody here still use NiZn? In which application? How do you avoid overdischarge?

Also, even after reading a lot about them (although mostly older posts from around 2010 to 15), I don't remember having read anything about their self discharge. Can they hold their charge over, say, 2 months, or half a year, without loosing a significant portion of the capacity?

 

[TinderBox (UK)]

All Dead, LOL

 

[fmc1]

I have used NiZn batteries for many years. I still have some. The last time I used some was in my grandson's nurf gun about 5 years ago or more and the extra voltage made a big difference in the distance the gun fired.


I would first try LSD NiMh AA's for your application because they are way better in every way the capacity, durability and cycle life are all way better. They are more readably available and way more tolerant to over discharge. The NiZn self discharge is way higher than modern LSD NiMd batteries but in my opinion about the same as older non LSD NiMh or NiCd's. They also don't like to be discharged below 1.2V so depending on your application this may not work for you. The only NiZn advantage is high voltage 1.65V nominal and 1.9V hot off the charger. They also hold the higher voltage even after steady discharge and they can handle high current discharge.


You also need a NiZn charger or a multi chemistry charger that supports NiZn. Powergenix stopped making AA NiZn batteries about 10 years ago. They were the most popular by far but if you see them for sale now it's very old stock or fakes. I have tried the Pkcell ones and they are just too inconsistent in capacity to be useful in series. Ansmann sells them and as a company I have always regarded their products as high quality, those would be the only ones I would even consider buying at this point in time. If a reputable vendor in the USA sold them, I would have tried them but to date I have not found one.


Frank

 

[n3eg]

I am using Ultracell NiZn batteries. I've had them for a few years now and they are still holding up. One application I've used the same 4 cells in is a Dremel tool for more RPM. They get reasonably hot in some grinding use with the Dremel and discharge to where it slows down, and then go right back in the charger. I also use them in old Kodak cameras that don't work with NiMh voltages.

I'd tell you how many years I've had them, but Ebay won't go back that far.

 

[wus]

I just realize I didn't follow up here, but can do that now.

I did not buy NiZn then, instead replaced the 2 AAs by 1 LiFePo4 plus 1 dummy AA. This works great, and even though I have to recharge the LiFePo4, whose capacity is closer to 500 than to the specified 600mAh, quite often, they still hold up well after all these years.

@fmc1 (if you are still here ): LSD NiMH is what I wanted to replace. The razor is likely designed to run off 2 alkalines, and as long as their voltage is near 1.5V it runs sufficiently fast. But they don't last long and since I didn't want to consume alkalines all the time I tried LSDs. But their lower voltage makes the razor too lame.

When I first tried the LiFePo4 I was a little afraid that its voltage of 3.6V would be too much, but after 4 years of use I can say, it still works, so it is fine.

 

[vicv]

I just realize I didn't follow up here, but can do that now.

I did not buy NiZn then, instead replaced the 2 AAs by 1 LiFePo4 plus 1 dummy AA. This works great, and even though I have to recharge the LiFePo4, whose capacity is closer to 500 than to the specified 600mAh, quite often, they still hold up well after all these years.

@fmc1 (if you are still here ): LSD NiMH is what I wanted to replace. The razor is likely designed to run off 2 alkalines, and as long as their voltage is near 1.5V it runs sufficiently fast. But they don't last long and since I didn't want to consume alkalines all the time I tried LSDs. But their lower voltage makes the razor too lame.

When I first tried the LiFePo4 I was a little afraid that its voltage of 3.6V would be too much, but after 4 years of use I can say, it still works, so it is fine.

Glad it worked out. As some more info, lifepo4 are actually 3.2V. They charge to 3.6v, but immediately drop to around 3.3v in a few seconds after being taken off the charger. And under load drop to around 3.2v and stay there until dead. So it makes sense a single cell would provide around the same voltage as two fresh alkalines. But unlike alkalines, they won't drop voltage in use. You'll be overdriving the motor a bit, but not too much

 

[Kestrel]

Strange coincidence, but for whatever reason I was thinking about NiZn & their self-discharge when I was running my (LiIon) electric razor this morning.