New Nickel Zinc AA Batteries

Hello there,


Recently i had acquired a set of four Power Genix nickel zinc AA cells that came with a charger. The cells are very different from the typical NiMH cells, mostly because the characteristic cell voltage is higher at 1.6v as compared to the NiMH which is 1.2v. This is exactly what i was looking for as some devices still like a higher voltage that normally only comes with a regular alkaline cell.

So far i havent tested them yet but i intend to soon. I was wondering if anyone else has used these kinds of cells yet and if so what results they got.

The strange thing that hit me right off was that the charger is advertised as a 1 hour charger yet for full charge it will take 4 hours. The other thing was that the charger will do four AA cells at one time, but will only do two AAA cells at one time (i dont have any AAA cells yet though, but might want some in the future).

The nice thing of course is that the cells exhibit a 1.6v cell characteristic but then again i dont know what the entire discharge profile is so i cant really say yet if the cells stays higher or dies down quickly...that will have to be tested. I also dont have any idea what the self discharge is for these kinds of cells. I normally go with NiMH like Eneloop or equivalent these days because that suites my applications best, but i have no long term data on these cells yet.

Any experiences or comments anyone would care to share would be appreciated.
I bought the package from Amazon for about 20 dollars US. I didnt think that was too bad but i just hope they really work as good as they seem to say they do.

Thanks...

Nickel-zinc battery - Wikipedia, the free encyclopedia

Ken

They appear to be a good type of rechargeable battery. They have a higher watt-hour rating but a smaller ampere-hour rating than a typical NiMH battery so their operating time, as compared to NiMH, will depend upon the load characteristics. Supposedly they work better in high power applications such as digital cameras.

The self-discharge rate seems comparable to standard NiMH but higher than the pre-charged, low self-discharge NiMH batteries now available. I like the low self-discharge NiMH batteries since, in many of my applications, the self-discharge of the standard batteries seemed to be the main factor discharging the batteries, not the normal load. For example I have a beard trimmer than used to require recharging every few months with a standard NiMH. It's now gone over a year without requiring a recharge after I installed a low self-discharge NiMH.

Hello again,

Ken:
Thanks for the link. I am hoping to dig up some other users too that have first hand experience. I'd like to hear some real life stories.

Carl:
What, you only shave once a year?
Seriously though, i have to charge mine once a month. Not sure what chem inside, probably NiCd i bet.
I really like the low self discharge type NiMH too. I have several of the Kodak brand, and now also one set of the illustrious Eneloops. Walmart used to sell the Kodak brand, not sure what happened to that deal though as i never see them there anymore. I actually tested very carefully one set of Kodak's and they did perform very well after a full 6 months of sitting on the proverbial shelf. All my other NiMH cells would be dead to the world after that long.

MrAl said:

Carl:
What, you only shave once a year?

Click to expand...

That's my beard trimmer for the parts I let grow, which I only use a few times a month. My shaver for the rest, I do use once a day, more or less.

The cell impedance is very important for many users. But here:
https://www.electro-tech-online.com/custompdfs/2010/08/powergenix-specs-aa.pdf

It seems pretty low. 3C (4.5A from the AA) is not an unacceptably high drop in voltage.

The exciting part is the charging cycle appears to be one where the cells could be paralleled to scale up to a larger batt, which can't reliably be done with NiMH. And the charge termination is straightforward like lithiums, not that transient dv/dt dip of NiMH which can be missed.

I wonder how the cycle life is? I didn't see a figure, and it's kinda beside the point because mfg-supplied figures and real-word figures are often two different things. And will they be damaged by deep discharge? NiMH can be taken down to 0V without damage. Lithium ion/li-po/lifepo4 will be damaged if you go below a certain voltage.

Note they can't be trickle charged like NiMH. The charge MUST be terminated.

The difficulty in scaling this up is that nickel is VERY expensive, and in limited supply. Like $60/lb IIRC. If you want much more for everyone to have an electric car, well, there isn't much more even if the price goes up. Lithium, however, well the brine pools it comes from now seem to have quite a bit, and if more is needed, it's a common element and there are plenty of other sources it might be possible to get it from.

A no name-brand "manufacturer" is advertising a "new" rechargeable battery? Who says so?
Why didn't name-brand battery manufacturers beat them to the market? Luck?

So Tesla has no place in building good electric automobiles because is not a "name brand" automobile factory ? Does it need to be government bailed to qualify ? Or they came up with their product because of luck ?
MrAl is simply exposing a new technology.

audioguru, no one beat anyone to market, these kinds of batteries have been around for a long time, they just weren't practical to make until relatively recently. There might be legal issues for commercial devices as well, while some loads might not mind the 1.6volt nominal voltage, other devices might go up in flames if used with them.

My Energizer AA alkaline battery cells are slightly more than 1.6V when brand new and none of my products using them have burst into flames.
My Energizer AA Ni-MH cells are 1.5V when fresh from the charger.

Oznog said:

The cell impedance is very important for many users. But here:
https://www.electro-tech-online.com/custompdfs/2010/08/powergenix-specs-aa-1.pdf

It seems pretty low. 3C (4.5A from the AA) is not an unacceptably high drop in voltage.

The exciting part is the charging cycle appears to be one where the cells could be paralleled to scale up to a larger batt, which can't reliably be done with NiMH. And the charge termination is straightforward like lithiums, not that transient dv/dt dip of NiMH which can be missed.

I wonder how the cycle life is? I didn't see a figure, and it's kinda beside the point because mfg-supplied figures and real-word figures are often two different things. And will they be damaged by deep discharge? NiMH can be taken down to 0V without damage. Lithium ion/li-po/lifepo4 will be damaged if you go below a certain voltage.

Note they can't be trickle charged like NiMH. The charge MUST be terminated.

The difficulty in scaling this up is that nickel is VERY expensive, and in limited supply. Like $60/lb IIRC. If you want much more for everyone to have an electric car, well, there isn't much more even if the price goes up. Lithium, however, well the brine pools it comes from now seem to have quite a bit, and if more is needed, it's a common element and there are plenty of other sources it might be possible to get it from.

Click to expand...

Hi Oznog,


Some good questions.

I didnt think yet about parallel operation, but yes that is probably an option. I dont like paralleling the other battery types. Yes, the charge termination is quite simple really, which i also like very much.

I dont know how the cycle life is yet. We'll have to see i guess as i test them as time goes on. I also dont know if deep discharge hurts them, but i dont think so at this point except they may not charge on the charger as with their charger the thing looks for various fault conditions. All they say is (get this), "If they dont take a charge because the charger rejects them, try again in 24 hours". All i could think was, wow, that's nasty.

Well, they actually are to be trickle charged to get the full charge but only for 4 hours, not to exceed 48 hours. That's after the fast charge of 1C or something like that though, not a full trickle charge to full charge. The trickle charge for the AA is 75ma but again it is really only supposed to be for 4 hours and only AFTER a normal fast charge.

Yeah i guess we'll have to see how the pricing goes over time too.


So far i found out a few more things about these cells after some tests which i'll enumerate here...

1. The cells come depleted, and when i first tried to charge them they didnt take a charge but the next day they did.
2. The terminal voltage is not 1.6 really, it goes as high as 1.8v after a full charge. That's pretty high so i would want to be careful about what i used them in. I had seen on the web that some people blew their flash units out, but that was because they were heating up (supposedly) from the more rapid cycle times. Still, 1.8v is considerably higher than 1.6 when there are a number of cells in series. This gets a big "CAUTION" from me anyway.
3. The Watt Hour capacity is different than the Ampere Hour capacity, im sure most of us know already, but for these cells that means the capacity in Ah comes out to only 1500mAh. That's a bit low these days. To top it off, one cell tested in at only 1000mAh and i wrote to the manufacturer about this. It could be because the impedance goes down with more charge cycles (this was the first one) and makes the voltage stay higher so the capacity can be measured as higher, but i'll have to wait till i drain them a few more times to tell for sure.
4. I have read that the Sub-C size was being used in Europe for cordless power tools, but was unable to find a supplier.


Conclusions so far:

Because there seem to be pro's and con's for these cells, it's starting to look like the only time we would want to use them is when we have a device that absolutely needs higher voltage to work properly, and doesnt work well with regular NiMH. NiMH are tried and proven, and yes their terminal voltage is lower, so that seems to be the technology to stick with unless you really need the higher voltage.
Supposedly they handle the high current demands of cordless tools so the Sub C size is supposed to be good for them. This could be a big boom to the industry for this application but i still have to see it work to say if it is really good or not.

Here are the discharge profiles for two cells:
**broken link removed**

audioguru, your alkalines read 1.6 volts for what, a few seconds maybe a minute after they start discharging? Notice the 1.8 starting voltage and it maintains 1.6 for 2 hours of the Nickle batteries. Most battery powered devices go straight to a regulator that should have decent tollerances, but some devices would be damaged by the extra voltage.

Sceadwian said:

audioguru, your alkalines read 1.6 volts for what, a few seconds maybe a minute after they start discharging?

Click to expand...

It depends on the load current. It might be seconds or hours.

Hi again,

Audioguru:
I just wanted to warn people just in case, knowing that some devices would not have a problem with the higher open circuit voltage. It is considerably higher than most other cells though, and even 0.2v is enough of a difference sometimes for a device designed for 1.5v with loaded alkalines. I have to leave it up to use end user to decide if their device can take it or not, i dont want to make any assumptions either way.

Anyway, i forgot to mention that that little blip in the green trace of one of the cells voltage curve occurred when the load was changed. At the start of the run i had a 10 ohm resistor across the two cells and the cells were in series. As cell #1 died down, i quickly disconnected it and connected the load of 10 ohms across the only cell left which was cell #2 of course. Now 10 ohms across two cells in series is like 5 ohms across each cell individually, so i later connected another 10 ohm resistor across cell #2 so that it's profile could be compared to the profile of the first cell more easily. That means first the voltage jumps up a little as the load changes to 10 ohms, then back down as the load changes back to 5 ohms.
The nice thing is, because of that small blip we can get a rough idea what the internal R is for this load current, and it came out to about 0.2 ohms which is fair i guess. That's the equivalent internal series R and not the impedance however.

I almost forgot to mention that i tried these cells in one of my Streamlight LED lights. That has 7 small white LEDs in it. The NiZn power it at about 220ma, and the LEDs get hot fast. The Eneloops power it at 120ma and the LEDs get warm.
I mention this light because with my other several LEDs blew out after using it with standard alkalines, which have a starting voltage around 1.6 and load down to 1.5v. The LEDs would get hot, start blinking on and off, and then blow out completely.
With an even higher voltage they get hot even faster, so i dont think i would use these NiZn cells in that light for example.
Back in the early to mid 1990's however, i used to use a calculator model TI85. It's no longer made but it was a nice calculator for it's time. Anyway, that thing would eat AAA alkalines for breakfast, lunch, and dinner, so i invested in a set of NiCd cells which were the only type made at the time that were rechargeable. What happened though is the display on the calculator didnt work well with the lower voltage of those cells so they had to be recharged really a lot even once per day or more. I turned to Rayovac for their new line of rechargeable alkalines, and well we all know that story, they work at a higher voltage but the cycle life is really junk being about 8 recharges or so. They advertised 50 recharges which wasnt bad really, but that was only if you dont deplete the cell all the way, which is not really a full charge either. They did work however and with the higher voltage (like alkalines) the display worked better until the cells got old after 8 recharges.
What i wanted to mention here is that i think these new cells would have been ideal for that application, because it really did need a higher voltage to work the display correctly. If they were around back then im sure i would have tried them. The new calculator i have (the TI85 eventually bit the dust and they didnt repair them after some years) i dont know if they would be required or not, but the only problem is that both calculators take AAA not AA, and the NiZn is not available yet in AAA size, only in AA size. That's a shame really as i have other apps i might like to try the AAA's in if they made them. As far as calculators with displays however, or maybe other devices that have LCD displays like that, the AA might work if they take that size of course. It's still a little bit of a gamble though if the 1.8 x 4 will burn up the calculator. I've seen fresh alkalines as high as 1.65v, and times 4 that's 6.60 volts total, and for the NiZn that would be 1.80 times 4 which is 7.2, so we're talking an extra 0.6 volts which for low voltage devices could be significant, so it's a little bit of a gamble.
While we're talking about applications, another no-no application would be some cordless phones that take AAA or AA size cells. Some phones say right in the manual NOT to use alkalines nor NiCd's, as NiMH is the only proper cell for that phone, so these would not be good for those phones.
Also as i have read on the web, the cycle time for camera flash units goes down with these new cells, which means you would be able to take more pictures in a given amount of time. The only problem is if the unit heats up too much it might blow out so you'd have to be careful there too.