NiZn AAA Batteries - Just received - Testing them

I just received 4 UltraCell AAA NiZn batteries from GreenForceCells
GreenForce UltraCells

The advertised capacity is about 700mAh (1145 mWh converted). However, so far in my test and in HKJ’s tests, they fall far short of that.
Interesting to note that PowerGenix 1.6v AAA batteries are advertised as 900mWh or 560mAh. Probably closer to an honest rating.

They all were sitting at 1.68v when they arrived and I thought “Hey, that’s good”…they were all alive and all had a reasonably good charge on them.

I’m running discharge tests on them now. The test is at .5 amp current down to 1.2v
They drop from about 1.9v to 1.65v VERY rapidly once I start the discharge cycle. (less than 60 seconds).

I’m using a fully regulated DC Power Supply to charge them (CC/CV).
The good thing about the DC power supply is that it automatically decreases the current as the battery reaches the preset voltage so overcharging is not a concern. REALLY handy on that.

So far here are my results …
Round 1 - (charged to 1.9v at 200mA, discharged to 1.2v at 500mA)
Cycle 1 - 150mAh
Cycle 2 - 340mAh
Cycle 3 - 479mAh
Cycle 4 - 475mAh
Cycle 5 - 461mAh

Round 2 - (charged to 1.8v at 110mA, discharged to 1.2v at 100mA)
Cycle 1 - 490mAh

I would consider 600mAh as success with these….but that aint happening.
It does seem the capacity is improving a lot with each cycle. By the 4th or 5th cycle I’ll probably know where they’re going.
My hope is to use these in my various automotive alarm remotes for my cars, vans and motorcycles… That’s why I bought them.
But I also have some CREE flashlights I could use them in and my new 700lm dual LED headlamp.

For discharging, I’m using a Turnigy Accucell 6 and discharging them at .5amps with a pre set cut off at 1.2v
The hobby charger is set to NiCd for the discharge but I don’t think that matters on the discharge cycle.

After I’ve cycled them 5 times I’ll post back the capacity results.

old imax B6 have a problem on lithium discharge not lowering the current at the end of the cycle, so often people use NiCd with the cutoff voltage you want

the cells are charged CC CV, so put on a DC power supply is an option to charge em

Thanks. The capacity seems to be bouncing back nicely so far. Hoping for a good outcome.

I tested them (Or some other generation of them) some time ago and was not very impressed with the capacity: http://lygte-info.dk/review/batteries2012/UltraCell%20NiZn%20AAA%201150mWh%20(Blue)%20UK.html

I saw your review and kinda hoped maybe they had improved over time. In your test, the best capacity result was only 475mAh when charged at 100milliamps. My results seem to be about the same with the “UltraCells” I received yesterday.
Your test results always seem to be very accurate.

From your charts, it appears your cutoff voltage was 1.1v whereas I used 1.2v for the cutoff voltage in my tests. I think the difference probably would have only been about 5mAh anyway because the voltage on these drops really fast once below 1.3v

PowerGenix AAA NiZn’s are “honestly” rated at 900mWh which is about 560mAh….so that is close to what I’m getting with Ultracells. I think I’ll achieve that on the ones I received by the 5th cycle…or close.

Kentli AAA cells are $7.50 PER CELL (lowest price I could find). More than I care to spend on AAA’s

Cycle 4 and 5 seem to have gone the wrong direction……

03 minutes - 25mAh - 1.60v
10 minutes - 82mAh - 1.54v
15 minutes - 124mAh - 1.64v
20 minutes - 166mAh - 1.65v
25 minutes - 207mAh - 1.64v
30 minutes - 249mAh - 1.63v
35 minutes - 291mAh - 1.61v
40 minutes - 332mAh - 1.58v
45 minutes - 374mAh - 1.53v
50 minutes - 415mAh - 1.44v
55 minutes - 457mAh - 1.23v
57 minutes - 461mAh - 1.20v

Not sure why. Charging anomoly ? I’m pretty sure I charged them the same each time but then with a CC / CV charger it’s possible to be off 50-100mAh maybe.

To anyone considering purchasing these cells……I can’t recommend them….EXCEPT……
In a VERY low drain application where the device has a built in discharge voltage cut off of 1.2v or higher.
In that particular application, the higher voltage of these batteries could be a perfect fit.

They are losing capacity with each cycle when charged to 1.9v and discharged at 500mAh to 1.2v.
The ones tested above are now only reaching 445mAh after just 5 or 6 cycles.
They are dropping in capacity fairly quickly. Again, they were charged to 1.9v on a CC/CV stable DC power supply and never discharged below 1.2v
I am adjusting the charge maximum voltage to 1.8v and 100mA charge current and adjusting the test discharge current to only 100mA

Maybe the PowerGenix cells are better quality?

Ironically, there are people who bought them on ebay and commented they are quite pleased with them.
I would assume those are people who don’t test their capacity.

I can’t see these as a good fit in most flashlights or any high current drain app or any device without a 1.2v or higher built in discharge cut off.

I bought the same cells months ago, They have to be charged gently and not discharged as low as possible, even so one of my cells died within the first week, I stopped using the cells.

I read this thread a couple of day`s ago but i could not remember what capacity i was getting, so i have put my cells though a refresh on my mc3000, And will post the results when they finish.

EDIT: My 3 AAA NiZn cells, 421mah, 412mah, 414mah

These NiZn cells are a waste of time really and i am glad i did not pay a lot for them, And would not buy them again.

John.

Thanks John.
Did you ever try the PowerGenix AAA NiZn cells?
I wonder if it’s the exact same cell……different wrapper?

I have two more of these that I have not yet “cycled”
I think I will lower the final charge voltage to 1.8v instead of 1.9v and see if that makes any difference.
The charge current has only been 100 - 300milliamps. Mostly around 150milliamps
I will limit charge current to 100 milliamps for the other two.

And because I intended to use these in VERY low drain devices that have a built in cutoff voltage of 1.3v I will limit discharge current to 100 milliamps also.

They still “might” work fine for the purpose I want them for.

I have only used the UltraCell NiZn, I bought them to use them in my old Sony mp3 player it takes an single AAA alkaline, I tried NiMh but the battery gauge only shows 3 of 4 bars when the NiZn shows all 4 bars, I think that`s what killed my first NiZn i forgot to remove the battery when i was not using it for a week and it went flat, the NiZn would not charge after that.

John.

I did a quick google search wondering what the advantages of NiZn batteries were (summary: not much - a tiny bit of extra voltage when fresh off the charger, and “theoretically” higher discharge capacity if you believe the marketing materials).

But self discharge is high, and reliability seems to be a MAJOR issue with NiZn - users report time and time again that many of their NiZn batts (like 50, 80, even 100%) are dead and useless (like 30mAh capacity) after a year of only 10 or 15 cycles total.

I’m trying mine in my alarm remotes which only draw .5mA current.
Even at just 400mAh capacity, I calculate they should power it for a month. That’s about what I get out of alkalines in them.
I’m using them in the remotes now to get the real world results but it will be about a month (or less)

At this point, I really believe they have to be VERY gingerly charged (like 100mAh current and only charged to 1.8v (not 1.9)
Then, they can’t be used in a high drain application. They are just not able to handle any stress it seems.
Also, any application that does not have a built in discharge voltage cut off will end in a dead cell.

I think there is a perfect use for these in 1.5v devices that draw VERY low current AND have a built in discharge voltage cut off of 1.2v or higher.

I will know in about a month.

I think HKJ (or somewhere it was said) that these cells can take a fairly high rate of charge.
That hasn’t been my experience. They seem VERY fragile and need low low rates of charge and discharge.

The NiZn chargers that most people use probably damage the batteries if the current is over 100mAh.
I don’t see 1amp charge on these batteries. I used 500mA and the capacity is down.
Maybe it was charging them to 1.9v? Maybe they’re just garbage inside?

Needing to handle them with such care and special regimens would hardly seem to make it worthwhile except in extrememly limited use scenarios. (Why can’t you just use NiMH in your remotes, do they specifically need the 1.5V?) Especially when part of the advertised advantage was supposedly that they were better for high drain devices.

As you said in the last few words above, I also wonder how much of the problems are:

  1. inherent to the engineering/design/chemistry of the cells, and
  2. simply shoddy manufacturing.

The fact that some cells survive but many die indicates problems with manufacturing, but the fact that no other company seems to be interested in the NiZn chemistry also tells me there may be issues with item 1.

The alarm remotes I use only run about 5 days on even the very best NiMh batteries because of the cut off voltage of 1.34v.
The NiMh batteries drop voltage rather quickly compared to the NiZn’s

The NiZns are pretty darn good at holding voltage ABOVE 1.3v for a much longer time it appears. Significantly longer.
They are similar to Alkalines in terms of time vs voltage drop.

For some reason, they like to hover between 1.5v and 1.6v for a very long time, then drop sharply once below 1.4v.

This is ideal for my low current devices that need voltage above 1.34 but can tolerate voltages as high as 1.8v.

For me charging them is no more complex than any battery charger. I pop them into a AAA cradle connected to my CC/CV DC power supply and go.

Has anybody tried the li-ion AAA cells that have an micro usb built in to charge them, They are regulated to 1.5v but what capacity are they.

I have a pack of 4 but i have not done any tests on them.

John.

Havent seen those. Have a link?
I’m interested in Kentli batteries.
They are LiPo inside I believe but are usually around $9.00 PER CELL (Yow!!)

I have the ZNTER AAA 400mah 4.25v 1.5v written on them.

EDIT: I think i tried to do a capacity test when i got them, but the low voltage protection must have kicked in so i lost the capacity information.

John.

I got 490mAh out of one of the test AAA’s by charging it at 100mAh and discharging it at 100mAh.

I’m not knowledgeable on how the lower discharge rate affects the discharge capacity results.

But……it appears that with 490 mAh, I can run my intended devices for a month or more. That’s more than enough to suit my needs for these batteries.

If they run the devices 2 weeks and 1 day I’ll be satisfied. Thrilled if they can run it for a month.

Just found another potentially stellar use for NiZn batteries.

Smoke detectors / CO detectors

Mine started beeping today. It had top quality Alkalines in it. The cut ouff (warning beep) voltage was 1.46v (I have no idea why so high, but that’s what it is)

In my book, alkalines have a LOT more life at 1.46v, but for some reason maybe smoke detectors have a high voltage threshold.

Anyway, this seems to be yet another superb application for NiZn batts. Just ordered a batch of PowerGenix AA’s for this application.

My only concern is that it uses multiple AA’s (3) and so the initial voltage will be 5.4v instead of 4.6v (ish)

But I’m fairly sure it will handle that difference ok.

I wonder if those Batteriser/Batteroo AA adapter sleeves would work they put out a constant 1.5v at low current, HKJ did a review of them a week or two ago and said they might be of use in certain circumstances.

John.