Any thoughts about NiZn battery, PKcell, EBL ?

[Constellation (Ryan)]

Hi guys,

Rechargeable batteries was my nightmare since my childhood, I remember the first day when my dad bought me a charger and batteries, after hours of waiting for the batteries to get fully charged, the first time that I put those batteries in my RC car, what a disappointment and heartbreak for me, It was like 50% used alkaline battery, lights are not that shiny and speed is not even close to that, even though I was so little, I clearly remind that I just suspected something was wrong with that batteries, so I asked my father, and he didn’t explain something useful , even now when I use my Phillips nose trimmer with NiMh batteries, it sounds like it’s dying; so low voltage has always been my problem.
Anyway, I didn’t find any informative chart/numerical based test about PKcell or EBL NiZn batteries, are they improved compared to their rivals ?

Or even 4150Mwh/2500 mAh XTAR Li-ion batteries compared to Kentli?

[raccoon]

Thanks for joining the party, Constellation!
For 1.5 volt (or 1.2 volt) rechargeable AA and AAA batteries, Eneloop batteries are king.
They last over a decade, and they’re not that expensive considering how awesome they are.
There are a couple of other brands that are up there with Eneloop, such as Ikea Ladda batteries, but for many people, Eneloop batteries are the way to go.

[gravelmonkey]

Welcome to the forum!

Generally, modern tech works well with NiMh.

Let’s start with: what specifically are you trying to power?

The voltage and current draw requirements are needed to give a good reccomendation.

Note also the (much) higher voltage of NiMh may damage certain devices.

Have a look at the charts on the comparator by HKJ.

It has not been updated in some time, but the comparisons are still valid-

Compare, eg, quality NiMh (eneloop 2450mah) with quality alkaline (Duracell Ultra Power AA).

Each line represents a discharge current, I’ve selected 0.2, 0.5, 1 and 2A as I dont know what your device(s) power demands are:

The line with most “voltage sag” on the leftmost side of the chart are the higher current draw, with decreasing current draw, the alkaline is able to maintain voltage- you’ll see the NiMh lines all track closely, this is due to 2A being “easy” for the NiMh to supply so the voltage doesn’t “sag”.

You’ll observe that the NiMh voltage is actually greater than alkaline for the majority of the discharge curve, due to the nature of the NiMh chemistry.

For a second comparison, you could plot, eg, quality NiMh (eneloop 2450mah) with the NiZn chemistry AA cells by PowerGenix that were tested:

For a 0.5a current draw, the Eneloop provides ~3Wh and the NiZn cell 2.1Wh. Total energy is greater from the Eneloop, so long as your device can utilise voltage down to 0.9V/cell.

I’m yet to see a device with low voltage protection configurable for NiZn- because these cells have much greater voltage, devices expecting alkaline or NiMh voltages will over discharge the cell perhaps to the point of damage. NiZn never really took off due to the “weird” chemistry, the low capacity, the requirement for a specific charger, and low longevity.

The third category of cells you asked about were lithium ion cells with built in converters. Most rechargeable lithium chemistry operates between 2.5v to 4.20v, it’s the physical property of the chemistry inside.

To get 1.5v for devices, these cells have a tiny electronics module soldered to the end(s) of the cells which convert the ~4v to 1.5v.

Cons:

1. No major manufacturer makes these (Duracell or energizer etc), you’ll have to get them from Amazon/eBay/AliExpress- I don’t own any myself so can’t reccomend specific brands, but there are a few guys here who do use these.

2. most need a dedicated/special charger

3. sudden shutdowns - when the lithium ion cell inside reaches 2.5V, the circuit will turn off the power as this is “empty”. Over discharging lithium ion cells is bad. I only know of one brand (xtar?) who have developed cells which will reduce voltage output when they are nearly empty so that your device (might) can alert you of low artery status.

Pros:

(Generally) Stable 1.5v output.

There are plenty of folks here more knowledgeable than I who have contributed to battery reviews, have a look through the forum for NiZn and Lithium ion AA reviews for “real world” experiences. Good luck with your search!

[Constellation (Ryan)]

Hi raccoon,
I would be join much sooner If I knew such a warm welcome awaits me

[Constellation (Ryan)]

Thank you for your complete explanation
And here I want to thank HKJ too, for his comprehensive work, hope he continues to do the great job.

[flydiver]

Suggest you read the reviews on NiZn. I had some long ago. They seemed like a good replacement for ‘old style’ NiMh that WERE disappointing. They did work…for awhile. Life span was short, charging was flaky, and capacity was low. They died pretty quickly. It does not seem like they have improved much, if at all.

The 1.5v AA lithium rechargeable DO work. At least some work. They come from relatively cheap to damn expensive. Unfortunately the cheap ones are often disappointing, and the expensive ones are quite expensive, but generally much better quality.
Xtar and Tenavolt seem to be the top performers in that field.
I’ve had OK short term results with some IMREN for half the price of the above.
No idea of long term viability yet.

If you want to risk an experiment I have a 3.2v LiFePO4 14500/AA in my Panasonic nose hair trimmer. Runs like crazy and hasn’t burned out yet . Electric motors are a bit more tolerant of overvoltage than some devices, but do so at your own risk.
You can also use these in some 2xAA devices with a dummy cell to slightly overvolt the device and it works fine if things fit correctly (length discrepancies between the dummy and the LiFePO4). I do this in a portable toothbrush.

You WILL need a special charger to deal with the lower lithium voltage. You CANNOT use a ‘regular’ lithium setting on a charger. SOME multi-chargers have a setting for this.
The Liitokala Liitokala Lii - 100 Mini Multi Function USB 1.2V 3.7V 3V 3.85V Battery Charger works fine.
(note-you need a dedicated charger for NiZn too. Most multi-chargers will not do NiZn).

[Constellation (Ryan)]

Thank you for sharing your experience, I will take the risk and try that 3.2V one for trimmer

[Mandrake50]

Just a great write up. Thanks!

[zerodish]

I had some in 2010. I was a bit worried about the high voltage of 1.9 volts and donated them to freegeek.org These would be useful for a 3 battery LED light. Kodak made a bunch of cameras that took 2 lithium AA batteries. These would work for about 2 photos with NiMh batteries. There is a place for them.

[flydiver]

A long time ago I had a bunch of NiZn due to disappointment with old chemistry NiCad/NiMh. With no evidence that the chemistry has been improved, I think the lithium rechargeable AA would work in that kind of application and probably be a lot more reliable…at least the decent ones, since there is an unfortunate amount of crap.
All my NiZn had low capacity and a short life. I’ve been using Li rechargeable AA/AAA for a several years now. All are in constant use, not a one has died. Capacity on ‘most’ is below claimed, but OK for the higher end ones like Tenavolt and Xtar. Too bad those are so expensive.
Capacity on cheap AAA has been pretty pathetic. They hold their voltage OK. Some handle OK current, others not so well. Tenavolt AAA are the only one’s I’ve tested that have been satisfactory.

[VgerSD (Virgil B)]

Ive been using NiZn for many years, and for some applications they’re great. Specifically high drain, low usage devices like an electric razor. With alkaline, the suggested, or nimh, the panasonic model my partner and I use is marginal. It doesn’t cut all that well, and occasionally grabs. With the NiZn, it cuts really well, and rarely grabs. I haven’t tried the lithium ion rechargeable, though looking at the power curves, it would probably be somewhere between alkaline or nimh, and NiZn, and probably OK. I also used to use a reach brand removable battery inexpensive toothbrush. it was pretty devent with NiZn, and not very good with other technologies.

As to battery longevity. I originally had 8 Powergenix cells, which are over 15 years old. One is still usable, though capacity is significantly lower than original, but it is still better in the shaver than alkaline or nimh. The first replacements are about 10 years old, are ultracell brand, 4 of 8 still working, and again still better in the shavers than standard alternatives, though they again drain significantly faster than new. Newest are EBL, 3ish years old, and the 4th one may have just died today. it came out of the original charger indicating charged, was put in a shaver, which barely operated, showed very low current when tested, faulted when put back in EBL charger, but seems to be charging OK in older urtracell charger. so status is unknown up to now. So batteries don’t last as long as nimh, but in some applications, work much better. Making a so so shaver and toothbrush work mcuh better, as you’d suspect from the voltage at high amperage curve charts.

As to device longevity. The toothebrush and shavers have had zero issues using the higher voltage/currect of the NIZN batteris. One had to be replaced because it was dropped, but was used consistently for 10 years with NiZn with no problems. 2 others for 3 years. toothbrush is only used occasionally, but is just fine. Ive also used them in LED flashlights, and they are a little brighter, but they’re not great for self discharge, so only good for times when you’re wanting slighly brighter for moderate amounts of time, and not for emergency when the lights go out flashlights. (so not a great trade off, not really recomended…) DON’T use them for old incandescent bulb flashlights. NiZn batteries burn out the bulbs in seconds.

So in my experience, for some applications, NiZn is distinctly superior. Specifically for high drain low to moderate duty cycle applications. None of the many articles I’ve seen have discussed this. Failure rate is higher, though some cells last for many years with lower amp hours, but still are better than mainstream alternatives for shorter periods of time. I think there is a significant chance that with more R&D, as has been applied to NiMh and Lithium Ion already, with significant improvements to the reliability of these technologies, NiZn could be a superior technology in some applications, with acceptable longevity.

I don’t have a PKcell vs EBL comment. I’m about to order some PKcell AA’s, as the EBL’s are starting to get questionable, but it will be 8 EBL aa’s vs 8 PKcell’s, and so not really a valid test.

I’ve also never seen any other reviewer comment on where NiZn can be superior to other technologies. Specifically high drain high power applications like a shaver or toothebrush. One article I looked at showed voltage at 3 amp drain, and all other technologies were almost immediately under 1.3 volt, with NiZn maintaining 1.5 volt plus for most of it’s curve, and 1.4 almost it’s entire curve. That’s a major advantage for some applications, and the author didn’t even bother to include the technology in the watt hour charts at the end of the article. Just saying it wasn’t popular earlier in the article. This is similar in almost every write up of the technology vs other more popular options, and seems pretty stupid and short sighted to me.