# Ni-Zn from UltraLast



## Mr Happy (May 8, 2010)

I made the mistake of going into Fry's and I saw these on the rack. Couldn't resist:







I'll test them and see how they do.

(Updated 12 May)

Here are some preliminary test results.

The cells are labelled 1.6 V, capacity 1350 mAh minimum.

Size: diameter 14.3 mm, length 50.3 mm. Standard AA size.

Weight: 25 g. About the same as a typical NiMH cell (cf. Eneloop 26 g).

The charger weighs 120 g and has a foldaway plug with no external power cord. It has worldwide voltage input and would be conveniently compact for travelling, dimensions about 115 mm x 68 mm x 38 mm.

It can charge 1-4 AA cells individually (but only 1-2 AAA cells). Charging time is about 1.5 hours according to the manual. That is about right for one or two cells, but may be longer for three or four cells. I have not tested that yet.

I had some trouble getting consistent discharge measurements on the cells, but they seem to agree reasonably well with the quoted 1350 mAh capacity. My problems with consistent discharge measurements might be because the charger is still charging when the green light comes on. To reach full capacity it may be necessary to leave the cells on the charger for a while to finish topping off before removing them.

A family of discharge curves for the same cell tested at different constant resistance loads is shown below.

I estimate the DC internal resistance to be about 25 mΩ, which means you could expect a voltage sag of about 0.025 V per amp of load. On that basis perhaps 5 A would be a reasonable working limit for these cells.






The high working voltage and low voltage sag is going to put a lot of power on tap. Rechargeable alkaline cells these are not.


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## Conan (May 9, 2010)

Nice to see NiZn getting to be more popular!


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## Bapman (May 9, 2010)

Mr Happy,

Do you think they're rebranded powergenix?

Ben.


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## Paul_in_Maryland (May 9, 2010)

That would be my guess. the charger looks awfully similar, and we've seen one rebranding, I think by Frye's or Ritz. Powergenix seems to have a powerful lock on the patents. Years ago, when small companies tried to muscle in on the lithium primary-cell AA market, we saw Eveready's lawyers fight them viciously. I doubt that Powergenix has Eveready's legal muscle, but it seems likely that the emergence of new brands can be explained by the company reaching out for partners.


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## ^Gurthang (May 9, 2010)

Looking forward to a review / comparo w/ NiMHs.....


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## 45/70 (May 9, 2010)

The NiZn cells do peak my curiosity, as well. It's good to see them becoming more available.

The only drawbacks I see with them are the shorter cycle life, and the limited number of chargers offered. The cycle life is not likely to be an issue for most people, myself included, but I've always been leery of bundled chargers. Some are good, most are not. Hopefully, as the NiZn chemistry catches on, this will change.

Looking forward to your observatins, Mr H. :thumbsup:

Dave


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## MarioJP (May 9, 2010)

I wonder whats the capacity on these cells??


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## core (May 9, 2010)

This looks like a potential support nightmare for them.

How are they going to explain to the average Joe that he can't charge his new "Ultralast Green" cells in any of the the "Ultralast Green" chargers that he has?

Some folks seem to be already confused by the PowerGenix cells and using NiMH chargers on them. :thinking: But when the brand name is exactly the same I gotta admit having a little more sympathy for them.


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## Mr Happy (May 9, 2010)

core said:


> This looks like a potential support nightmare for them.
> 
> How are they going to explain to the average Joe that he can't charge his new "Ultralast Green" cells in any of the the "Ultralast Green" chargers that he has?
> 
> Some folks seem to be already confused by the PowerGenix cells and using NiMH chargers on them. :thinking: But when the brand name is exactly the same I gotta admit having a little more sympathy for them.


Yes, I have the same thoughts. The instructions that say you should only charge the NiZn cells in the NiZn charger and only NiMH cells in NiMH chargers are hidden in small print and IMHO are not prominent enough. The average person is very easily going to miss this and not realize the difference. 

When I picked the batteries off the rack I only recognized they were NiZn because I already know what NiZn is all about. Most people do not have that knowledge and will just assume they are "rechargeable batteries". The charger itself says nothing on the front at all to indicate it is not for NiMH.

I often observe people buying batteries and chargers in Fry's and generally they have no clue what they are looking at. Throwing something like this into the mix without marking it out as special in big bold letters is not going to lead to good results. It's also a marketing opportunity missed. These batteries are indeed special: why not make a big song and dance about it?


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## Flying Turtle (May 9, 2010)

I think these batteries may be just what my digicam needs with that extra bit of voltage. And the flashlights will be happier, too. Very close to pulling the trigger on some of these.

Geoff


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## jasonck08 (May 9, 2010)

Looking forward to discharge graphs...


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## core (May 9, 2010)

Mr Happy said:


> It's also a marketing opportunity missed. These batteries are indeed special: why not make a big song and dance about it?



I think that big yellow sticker with the "PUNCHES UP" very nearly qualifies as song and dance.  They definitely should have called them something else though. Now they've got Ultralast Green Everyday Rechargeables, Ultralast Green High Power Rechargeables, Ultralast Green PowerPunch, Ultralast Solar Light Rechargeables, all different chemistries and that's not even getting into the Li-Ions they got. They all look nearly identical.

At least with the PowerGenix ones you can't miss the "High Voltage" printed on it. And most importantly a PowerGenix charger will charge your PowerGenix cells. Nice and easy to keep straight.

Not sure if the boxing-related slogan goes so well with the save the earth "green" they're trying to push.

Slightly catchy though. I got one for them:
"Punch up the performance. TKO your bulbs!" Hah.

Anything is better than Mary Lou Retton saying it's *super* charged.


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## Mr Happy (May 9, 2010)

core said:


> I think that big yellow sticker with the "PUNCHES UP" very nearly qualifies as song and dance.


Yes, I was overlooking that when I wrote it. 

But the outer wrapping gets removed and thrown away, and then the charger and batteries look entirely similar to regular NiMH chargers and batteries. The lettering that says "Charge ONLY in a NiZn charger" is in the smallest possible type and at the very end of all the other yada yada yada warnings about disposing in fire etc. OK it says NiZn 1.6 V in slightly bigger lettering, but is a non-technical person going to know what that means?


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## Paul_in_Maryland (May 9, 2010)

*Re: Ni-Zn from UltraLast: capacity*



MarioJP said:


> I wonder whats the capacity on these cells??


about 1600 mAh at a discharge rate of 1 amp, 1500 mAh at 2A. Subtract 8 percent a month for self-discharge. Four or five charging cycles are needed to achieve full capacity.


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## PhantomPhoton (May 9, 2010)

I'm curious whether they'll handle a ~5A draw and what the voltage sag will be if they can handle it.


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## MarioJP (May 9, 2010)

PhantomPhoton said:


> I'm curious whether they'll handle a ~5A draw and what the voltage sag will be if they can handle it.



I would not be surprise if they can handle that kind of current draw with little voltage sag I remember seeing a chart that at 10A the voltage was around 1.5v. Cant find that chart I know its somewhere here on these forums.

Though I would imagine at those current draw the cell would have a very limited cycles.

These cells are true heavy duty cells for the most part.


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## Curious_character (May 9, 2010)

Boy, those things sure walk, talk, and quack like the old rechargeable alkaline cells first marketed in the '70s or earlier, then some time later, dying out both times. The capacity of the rechargeable alkalines would drop considerably each charge cycle, and the internal resistance would increase pretty dramatically. So they became useless for even moderate drain applications after a few cycles. NiMH were vastly superior for high drain applications, and primary alkalines more practical for low drain applications. So, try as the marketers did, they never really caught on.

Are there any good specifications for these cells? I'd like to see if they're (yawn) the same old thing with some lipstick on, or if they're really something new.

My experience with Fry's Ultralast lithium cells was dismal, so I wouldn't judge all NiZn or any other cell by how Ultralast brand cells perform.

c_c


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## Mr Happy (May 9, 2010)

There seems to be a bit of variability between cells. Or maybe they need a few cycles to break them in. I'm trying to find out what's what.


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## Mr Happy (May 10, 2010)

Preliminary test results added to first post.


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## Lynx_Arc (May 10, 2010)

makes you wonder if it is possible for them to make a charger for nimh and nizn both. It would make things simpler if you only had one charger to prevent accidental charging of cells in the wrong charger. would nimh cells even charge in this charger or is it an accident waiting to happen?


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## core (May 10, 2010)

Mr Happy,

Did you use the included charger or another CC/CV charger? Assuming you used the stock charger, how did you determine when the cells were fully charged?

The manual that came with my PowerGenix charger left a lot to be desired. It states that once the green LED turns on, the quick charge is complete and it has switched to trickle charge. But there is no indication for when the cells are 100% charged.

It does say "up to" 4 hours, but given that they don't even explain that the current is halved when charging 4 cells at a time, I have little faith in the PowerGenix manual as a whole. And the current draw is too small to be measured with my Kill-A-Watt.

So short of getting an ammeter in the middle, I'd love to have another way to know for sure when they are fully charged. Especially before I do any measured discharge tests.


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## Mr Happy (May 10, 2010)

core said:


> Mr Happy,
> 
> Did you use the included charger or another CC/CV charger? Assuming you used the stock charger, how did you determine when the cells were fully charged?
> 
> ...


I used the included charger. The UltraLast manual does not say anything about a topping off phase, it just says the charge is 80-90% complete when the green light starts flashing and is 100% complete when the green light goes solid. However, given my difficulties in obtaining consistent discharge measurements I began to suspect the cells are still topping off when the green light comes on. What you say about the PowerGenix manual appears to confirm it.

As to the charging time, the back of the charger implies the charging current is halved with 3-4 cells compared to 1-2 cells. The UltraLast manual says nothing about this, it just says the charging time is "~1.5 hours". Perhaps it is just following the PowerGenix manual there.

Regarding the actual measured capacity the graph in post #1 can be taken as typical. The final measured capacity may vary by ~50—100 mAh according to how much topping off the cells get. I did several discharge tests and they were all in the same ball park.


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## jcw122 (May 10, 2010)

I'm eager to see how NiZn mature as well. I'm hoping for a safer alternative than Li-Ion, while being powerful and long lasting.

Can I assume that these cells would be safe in my Quark? The limit is 4.2v, and 2x1.6=3.2v.....should that yield slightly higher brightness such as 1x Li-Ions would because of a higher voltage?


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## MarioJP (May 10, 2010)

These do look like Nimh cells lmao. I am guessing if you put them in a nimh charger i think the cells won't charge or the charger will refuse to charge them as it would think you have inserted a alkaline cell??.


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## core (May 10, 2010)

Mr Happy said:


> The UltraLast manual does not say anything about a topping off phase, it just says the charge is 80-90% complete when the green light starts flashing and is 100% complete when the green light goes solid. However, given my difficulties in obtaining consistent discharge measurements I began to suspect the cells are still topping off when the green light comes on. What you say about the PowerGenix manual appears to confirm it.



Yeah my manual mentioned a "flashing" indication as well but the charger has never flashed. Guessing it was a translation issue. The cells are definitely just starting to top off when the solid green comes on. And unfortunately the solid green never goes out.

Which really is starting to tick me off. The only way to ensure they're fully charged is to simply leave them on there for an enternity and guess?? I'm somewhat surprised you only found 50-100mAh difference regardless of how much you charged them: 20% of 1350mAh is still 270mAh. And worse yet, that 20% you're losing is all in the higher voltage phase! (You know, the whole reason we bought the things?)

Actually I'll just quote from the PowerGenix manual:

_5. After quick charge is completed, the green LED will flash and light to indicate that the quick charge is completed and batteries are ready for use. However once the green LED lights, the charger switches to "trickle" mode. Leaving the batteries on charger *up to 4 hours* (charger will terminate charge automatically) will provide maximum capacity_

I'm hoping/assuming that this 4 hours is in the constant voltage phase and thus won't be affected by having 3 cells in there vs. 2. Yet another unknown. Plug 'n pray. 

Really love the cells but someone needs to come out with a real charger.

If I sound a little irritated it's because I just popped open my device and found that one of the cells had been driven down to 1.30V open circuit while the other was just starting to drop below 1.6V. These were charged at the same time yesterday. I guess I didn't wait enough hours eh? And with only 1 LED how does the 4 hour limit work? Whole charger shuts down if the first cell hits the time limit? At any rate, they obviously didn't get charged properly.



MarioJP said:


> I am guessing if you put them in a nimh charger i think the cells won't charge or the charger will refuse to charge them as it would think you have inserted a alkaline cell??.



The BC-700 will happily attempt to charge them. Found that out the hard way when I missed the end of a discharge test.


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## MarioJP (May 10, 2010)

core said:


> The BC-700 will happily attempt to charge them. Found that out the hard way when I missed the end of a discharge test.



Oh that's right with the exception of the La crosse. Weird how things works like that now doesn't it lol. Isn't just me or are the powergenix chargers look god awful lol. How do you know when the cells are fully charged. Don't like chargers with basic indicators.

This reminds me of the 15 min energizer charger. Manual says batteries are charged when the light turns green. Turns out not all cells are getting charged equally and I found that out when one cell would die quicker than the other and their manual was confusing lol.


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## Bapman (May 10, 2010)

Core,

Another drawback of the nizn batteries is that according to 
maintenance charging procedure you have to recharge every month,
or if the volts per cell < 1.68v (see link below)

http://www.powergenix.com/charging.php


Ben.


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## core (May 10, 2010)

MarioJP said:


> This reminds me of the 15 min energizer charger. Manual says batteries are charged when the light turns green. Turns out not all cells are getting charged equally and I found that out when one cell would die quicker than the other and their manual was confusing lol.



Ah yes, in my younger foolish days I too had an Energizer 15 "Battery Toaster". It became quickly apparent to me that they weren't charging equally because I'd get one out of the bunch that wasn't quite hot enough to burn my hand. So he got placed back in the oven for another pass. 

Got fed up with trying to determine which ones were properly charged and just started charging them one at a time. That was feasible with the 15 minute Enertoaster. But doing one NiZn cell at a time when it takes 1.5+4 hours? Errr nope can't do that.



Bapman said:


> Another drawback of the nizn batteries is that according to maintenance charging procedure you have to recharge every month, or if the volts per cell < 1.68v



I don't mind that actually. These aren't claiming to be low self discharge, and a month is a long time for a cell not to get used. It's not like you'd keep these around in your emergency light, portable radio or anything else that just sits around. Those devices generally wouldn't need the extra voltage and Eneloops would work fine for those cases. Only time I'd see this being a drawback is for those folks that use them in remote controls for the extra range.


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## MarioJP (May 10, 2010)

Bapman said:


> Core,
> 
> Another drawback of the nizn batteries is that according to
> maintenance charging procedure you have to recharge every month,
> ...



I guess that's one advantage that Eneloops has is storage.


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## Mr Happy (May 10, 2010)

core said:


> Yeah my manual mentioned a "flashing" indication as well but the charger has never flashed. Guessing it was a translation issue. The cells are definitely just starting to top off when the solid green comes on. And unfortunately the solid green never goes out.


It's true, I've not seen the green light flash either. As far as I can tell, the red light goes out and the green light comes one.

For my discharge test in post #1 the cell was removed soon after the green light came on. I didn't time it exactly, but it would have been after 1.5 hours and less than 2 hours. I will look more closely into this now I'm starting to get the picture.


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## r1gm1n (May 10, 2010)

The company that makes these batteries moved their offices from San Diego to Tijuana last month.


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## Mr Happy (May 10, 2010)

r1gm1n said:


> The company that makes these batteries moved their offices from San Diego to Tijuana last month.


It was a sales office apparently. They must really be going through hard times if they felt the need to move a sales office from the USA to Mexico. Or maybe Uniross is a hard-hitting corporate slave driver...

Anyway the corporate organization of UltraLast is something you could make a separate thread. It has little to do with NiZn batteries. Keep this thread on topic.


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## r1gm1n (May 11, 2010)

Mr Happy said:


> It has little to do with NiZn batteries.


Quantaray Super Z, UltraLast PowerPunch, and PowerGenix NiZn not only share a common chemistry but also share a common defect. The nipple is so short that the body, _*in some applications*_, makes contact with the battery holder and the nipple cannot reach the positive contact. This commonality MIGHT be explained by a little snippet from the San Diego Union-Tribune a few days ago:
*N B* has been named director of consumer sales at PowerGenix, a San Diego company that makes rechargeable batteries. B previously was vice president of sales at Ampergen


Mr Happy said:


> Keep this thread on topic.


Trying to show why I think that *Ni-Zn from UltraLast* is just a rebranding of the same batteres I have been using for 6 months seemed on topic to me. Sorry.


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## HarryN (May 11, 2010)

They look like interesting cells for a lot of applications. 

I am guessing though that my 1 yr old Triton II can't charge them though. :shrug:


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## 45/70 (May 11, 2010)

HarryN said:


> They look like interesting cells for a lot of applications.
> 
> I guessing though that my 1 yr old Triton II can't charge them though. :shrug:



That's funny Harry, I've been thinking how one might charge NiZn cells with a hobby charger.

This probably wouldn't work, but I thought of putting two NiZn cells in series and charging on "LiPo storage" charge. Since NiZn cells use a CC/CV algorithm for charging, you'd have the two cells charging during the CV stage at 3.8 Volts, which would be 1.9 Volt/cell. Humm :thinking:

Dave


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## bigchelis (May 11, 2010)

These batteries are miracle enablers:thumbsup:


I got these DX MC-E P60 drop-ins that have been tested (3 samples) both by MrGman and myself at 350ish OTF with an IMR 18650 cell.

Then I got the Javeling 3AA hosts. I put 3 Tenergy NiMH AA cells and got 450ish OTF, not bad right. Wait; theres more!!!!

I put 3 of these Ultralast Green NiZn AA cells. I got 580ish OTF and the lumens were not dropping like I expected. I then re-tested the 2 other P60 MC-E samples and I got the same spectacular results. That is nearly 600 OTF lumens with a P60 hosts.

bigC


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## Mr Happy (May 11, 2010)

45/70 said:


> This probably wouldn't work, but I thought of putting two NiZn cells in series and charging on "LiPo storage" charge. Since NiZn cells use a CC/CV algorithm for charging, you'd have the two cells charging during the CV stage at 3.8 Volts, which would be 1.9 Volt/cell. Humm :thinking:


As far as I can tell they have limited self-discharge so they wouldn't self-balance very well if you charged them in series. When they come off the charger they seem to sit at about 1.84 V or thereabouts and unlike LiFePO4 cells this voltage does not drop down to a lower resting voltage at any great speed. They will still be at 1.84 V the following day.


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## HarryN (May 11, 2010)

I wonder if some kind of voltage divider could be rigged up to charge them from the Triton? Maybe I could make it look like a 1 cell Pb acid or 2 cell NiCd, and charge up a batch in parallel. It sounds like since they don't self balance very well, then it sort of forces one to do the balancing actively.

BigChelis - that sounds neat. I need to come to a GTG sometime and try out that sphere.


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## jcw122 (May 11, 2010)

I wanna see NiZn's in a TK40 haha


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## bigchelis (May 11, 2010)

jcw122 said:


> I wanna see NiZn's in a TK40 haha


 

I want to see that too.....The TK40 is regulated so, I don't think the current will go up much or anything at all.


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## Mr Happy (May 11, 2010)

jcw122 said:


> I wanna see NiZn's in a TK40 haha





bigchelis said:


> I want to see that too.....The TK40 is regulated so, I don't think the current will go up much or anything at all.



Don't the TK40 instructions specifically say not to use Energizer Lithiums? I would say if you tried to use NiZn cells your expensive light would go  and take a dump:


That would leave you feeling :eeew: if not .


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## jcw122 (May 11, 2010)

Mr Happy said:


> Don't the TK40 instructions specifically say not to use Energizer Lithiums? I would say if you tried to use NiZn cells your expensive light would go  and take a dump:
> 
> 
> That would leave you feeling :eeew: if not .



Do energizer lithiums run around 1.8v as well? I couldn't figure out what voltage they ran.


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## Mr Happy (May 11, 2010)

r1gm1n said:


> Trying to show why I think that *Ni-Zn from UltraLast* is just a rebranding of the same batteres I have been using for 6 months seemed on topic to me. Sorry.


Perhaps you should just come right out and say what you want to say, rather than quoting random press cuttings that leave everyone clueless?

I think we all understand that these NiZn cells share common PowerGenix technology and come from the same factory in China. However, I can find no obvious evidence that PowerGenix is the same company as Ampergen, the owners of UltraLast. Ampergen has a different HQ and different shareholders. My assumption is that Ampergen has a redistribution agreement and is putting their own branding on them.

This thread is about the performance and availability of the cells. The UltraLast angle is of interest since it indicates these cells are finding more retail outlets and are becoming more widely available.


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## Mr Happy (May 11, 2010)

jcw122 said:


> Do energizer lithiums run around 1.8v as well? I couldn't figure out what voltage they ran.


Yes, they have a much higher operating voltage than alkalines or NiMH.


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## TakeTheActive (May 11, 2010)

Mr Happy said:


> ...I would say if you tried to use NiZn cells your expensive light would go  and *take a dump*:


Thanks for using  in context - I never watched it (Knight?) long enough on the *More Smilies* screen   :eeksign: to understand its meaning.


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## 45/70 (May 11, 2010)

Mr Happy said:


> As far as I can tell they have limited self-discharge so they wouldn't self-balance very well if you charged them in series. When they come off the charger they seem to sit at about 1.84 V or thereabouts and unlike LiFePO4 cells this voltage does not drop down to a lower resting voltage at any great speed. They will still be at 1.84 V the following day.



Well, if they respond to series charging like Li-Ions do, then it wouldn't work. It just seemed like the "LiPo" (lithium polymer, not LiFe) storage charge setting would work out almost perfectly for two NiZn cells in series. I read somewhere that the CV stage for these NiZn AA cells terminates at 75mA. You could set the charge rate at 700mA, most hobby chargers terminate at 1/10th C, so the charge would terminate at 70mA/3.80 Volts. Oh well, another bright idea . 

I'm keeping an eye out for some of these NiZn cells. So far I haven't seen any yet. I would really prefer to not have to have another charger, especially one which is pretty much unproven, such as is bundled with the cells. It would also be much nicer to be able to monitor the charge, have a discharge function and so on, as with a hobby type charger.

Dave


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## Mr Happy (May 12, 2010)

45/70 said:


> I'm keeping an eye out for some of these NiZn cells. So far I haven't seen any yet. I would really prefer to not have to have another charger, especially one which is pretty much unproven, such as is bundled with the cells. It would also be much nicer to be able to monitor the charge, have a discharge function and so on, as with a hobby type charger.


The "one hour" charger that comes with these cells seems pretty reasonable. It charges one or two cells at least in under two hours and the cells remain entirely cool during charging. I have been able to discharge the cells in the C9000 and get capacity measurements that way.


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## core (May 12, 2010)

It charges them to 'some unknown state of charge' in under 2 hours. Which in real world use I've found to be terribly uneven at worst, and lucky voodoo at best.

This does not fall under my definition of "pretty reasonable" by any stretch.


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## Mr Happy (May 12, 2010)

Updated post #1 with discharge graphs at different loads. These cells seem to take high loads very well. They handle a 2C discharge at about 2.5 A with no trouble at all.

I'm measuring a working capacity close to 1300 mAh in most of my tests. At one point I got nearer 1350 mAh, but I can't seem to reproduce it now. Later I will cycle and measure a set of four cells to get an idea of the variability between them.


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## core (May 12, 2010)

It might be beneficial to leave one of the cells only shallowly discharged before charging the group, if you're looking at variability. I was planning on doing something along those lines but I don't have the fancy tools at my avail for the data logging. 

Not to mention these beasts are running me 2 cycles a day per cell (not necessarily a bad thing) and I have few spare cells as a consequence. Good excuse to buy more I suppose.


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## TakeTheActive (May 12, 2010)

Mr Happy said:


> ...I estimate the DC internal resistance to be about 40 mΩ...


For the curious, would you please explain how you arrived at the following resistance numbers:
'_I estimate the DC internal resistance to be about *40 mΩ*_'
*2.2Ω* (~0.7A, 0.5C)
*1.1Ω* (~1.4A, 1.0C)
*0.6Ω* (~2.5A, 1.9C)
Thanks! 

An '_Aside Question_': Is there a shortcut to displaying *∆* and *Ω* in forum posts? (Copying Character Map / Font SYMBOL / '*∆*' shows up as a '*D*' for me.)


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## Mr Happy (May 12, 2010)

TakeTheActive said:


> For the curious, would you please explain how you arrived at the following resistance numbers:


I have since updated my estimate from 40 mΩ to 25 mΩ.

Here is a sample calculation. I put two different loads on the cell and measured the voltage and current at each load, switching rapidly back and forth between each load and waiting a second for the voltage to stabilize each time.

First load: V1 = 1.640 V, I1 = 1.477 A
Second load: V2 = 1.612 V, I2 = 2.594 A

The internal resistance is then given by

Ri = (V1 - V2) / (I2 - I1) = 0.0251 Ω

Such a measurement can only be an estimate. The value obtained this way tends to increase as the cell discharges. It is perhaps 30 mΩ at the mid-point of the discharge.

The values 0.6 Ω, 1.1 Ω and 2.2 Ω are the load resistances I used to discharge the cell under test. I measured these resistances more accurately as 0.621 Ω, 1.11 Ω and 2.10 Ω for the actual calculations.

(To get the Ω and ∆ symbols I just copy/paste from Character Map and assume that "magic happens" behind the scenes.)


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## 45/70 (May 12, 2010)

TakeTheActive said:


> For the curious, would you please explain how you arrived at the following resistance numbers:



In addition to the info Mr H provided, I think that it is important to note that there are a lot of possible variables when determining internal resistance of cells, or any other resistance calculations.

The "test setup" is prone to a lot of variability in and of itself. The means of connecting the leads, ambient temperature, temperature of the cell, the quality of the DMM and the leads/probes/connectors, or whatever you're using to measure'/calculate the resistance, and so on. Unless you're using high end equipment, the results likely will be more or less meaningless, except for relative comparisons, using the exact same setup. Even with good equipment, the results can be suspect due to the many variables involved. Unless a large sampling is used, multiple measurements are conducted on each sample, and the overall end results averaged out, the results are more of a "guesstimate".



Mr Happy said:


> (To get the Ω and ∆ symbols I just copy/paste from Character Map and assume that "magic happens" behind the scenes.)



That's how I do it. Love the "magic" part! :naughty:

Dave


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## Mr Happy (May 12, 2010)

45/70 said:


> the results likely will be more or less meaningless





While I agree with your observations about measuring a consistent value for this parameter, I think I would say the results are "less" meaningless. They do tell us something.

For instance, the IR of these cells is measurably less than typical NiMH cells, maybe even half or one third of the value. When looking at voltage sag and cell heating at high discharge rates this is useful to know.

These cells barely get warm at 2.5 A discharge, whereas I think Eneloops do get quite warm at the same rate. Maybe I can do some temperature measurements to compare.


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## 45/70 (May 12, 2010)

Mr Happy said:


> While I agree with your observations about measuring a consistent value for this parameter, I think I would say the results are "less" meaningless. They do tell us something.



I agree, your results do have value for comparison, that's not what I was getting at. As I mentioned, you are using your setup, and that is a relative constant.

What I'm saying is that when two people try to determine the IR of NiZn cells, one out in his shop in the snow at the North pole, and the other in So Cal, one is using his Toys"Я"Us DMM with coat hanger leads, the other is using a Fluke 8xxx bench meter with gold plated leads with soldered connections, the results may be the same, but more than likely, they will be different.

I think TTA possibly, is looking for a definitive value for the IR of NiZn cells, but I don't think there is one, short of what for example, a battery manufacturer comes up with. And even these lab type results would be subject to the conditions under which the values were obtained.

If ten of us tried to determine the IR resistance of the same NiZn cell we passed around, I'm certain we'd come up with ten different answers. I wouldn't be surprised if the results varied by as much as 25%, or more. As you said a couple posts back, we're dealing with estimates here. I was just pointing out some of the reasons why that is. 

Dave


----------



## HKJ (May 12, 2010)

The problem with measuring the Ri of a cell is that it is depending on a lot of parameters, like age of cell, temperature of cell, charge condition of cell, connection to cell and measuring method, it is very difficult to standardize all these parameters.
I could add a description to my DMM guide, but that would only fix one of the variables and only for people that read that guide.


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## 45/70 (May 12, 2010)

Mr Happy, what is the actual circuit voltage of these cells when being charged?

The reason I ask, is that in the "Quick Charger" .pdf it states the charger output as 1.6V for 1, 2 ,3, or 4 cells. Looking at the "Fast Charger" .pdf however, it states this charger's output as "3.2V*2". Does this not imply that the cells are being charged in series?

I apologize for going a bit OT here, but I'm still thinking about using a hobby charger to charge these cells. Of course, I still have to find some. 

Dave


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## Mr Happy (May 12, 2010)

45/70 said:


> Mr Happy, what is the actual circuit voltage of these cells when being charged?
> 
> The reason I ask, is that in the "Quick Charger" .pdf it states the charger output as 1.6V for 1, 2 ,3, or 4 cells. Looking at the "Fast Charger" .pdf however, it states this charger's output as "3.2V*2". Does this not imply that the cells are being charged in series?
> 
> I apologize for going a bit OT here, but I'm still thinking about using a hobby charger to charge these cells. Of course, I still have to find some.


I have the "Quick Charger". I have not measured it, but according to spec the cells are charged to 1.9 V. The Fast Charger may well charge pairs in series, but perhaps it also includes an internal cell balancer?


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## MarioJP (May 13, 2010)

whoah only 300mA. I thought these cells can't be slow charged??


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## Conan (May 13, 2010)

core said:


> It charges them to 'some unknown state of charge' in under 2 hours. Which in real world use I've found to be terribly uneven at worst, and lucky voodoo at best.
> 
> This does not fall under my definition of "pretty reasonable" by any stretch.



Please define "terribly uneven". My cells normally come off the charger with three cells at 1.83 and one at 1.82.


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## Mr Happy (May 13, 2010)

Conan said:


> Please define "terribly uneven".


Well, for instance, after I finished plotting discharge curves for these cells I charged all four of them fully and ran a discharge test on the C9000 at 500 mA. I got the following capacity measurements:

1365 1465 1370 1413 mAh

This is a lot more variation than I was expecting.

Unfortunately I didn't keep track of which cells had more discharge cycles on them than others, so I can't relate this variation to the amount of use. That will have to wait for another test where I take four fresh cells and treat them all equally.


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## 45/70 (May 13, 2010)

While not terribly out of balance, those figures would put a big dent in the use of these cells in series applications, without watching them closely. On the other hand, if the cells were kept and used in "sets", maybe the results would be closer. Or, maybe these cells are more resistant to reverse charging. I know, it's too early to tell. 

After observing from the sidelines for a while now, I'm starting to get worked up about this NiZn chemistry! That's all I need, more cells appropriate only for specific purposes..... and maybe a charger, as well. 

Dave


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## MarioJP (May 14, 2010)

Ok finally I am trying these cells and first thing I am realizing is that these cells do not like to be over discharged AT ALL!. Did 2 cycles on them so far and everything was going good until I left it in my mobile usb charger and realized they have been severely over discharged. One cell in particular is stuck at 0.46v .

No way in hell are these are THAT FRAGILE?? Anyone encountered this problem with the nizn cells yet?


----------



## Lynx_Arc (May 14, 2010)

MarioJP said:


> Ok finally I am trying these cells and first thing I am realizing is that these cells do not like to be over discharged AT ALL!. Did 2 cycles on them so far and everything was going good until I left it in my mobile usb charger and realized they have been severely over discharged. One cell in particular is stuck at 0.46v .
> 
> No way in hell are these are THAT FRAGILE?? Anyone encountered this problem with the nizn cells yet?



it is possible the charger is like many smart charger and won't even try and charge cells below a certain voltage. try and hook the cell in parallel with a charged cell for a very short time to give it a boost and then the charger may go ahead and charge it. be careful not to leave it connected and overheat though as I don't know how hard the charged cell would try and recharge the dead one for sure.


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## MarioJP (May 14, 2010)

Lynx_Arc said:


> it is possible the charger is like many smart charger and won't even try and charge cells below a certain voltage. try and hook the cell in parallel with a charged cell for a very short time to give it a boost and then the charger may go ahead and charge it. be careful not to leave it connected and overheat though as I don't know how hard the charged cell would try and recharge the dead one for sure.



1+:thumbsup:. Thank You! this method worked!. I used the multimeter to measure the amount of current going in to the dead cell. That cell is now recovered and back to normal.

I hope these cells are forgiving for deep discharges.


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## Lynx_Arc (May 14, 2010)

MarioJP said:


> 1+:thumbsup:. Thank You! this method worked!. I used the multimeter to measure the amount of current going in to the dead cell. That cell is now recovered and back to normal.
> 
> I hope these cells are forgiving for deep discharges.



my bc900 won't charge cells when they get too low, I put them in my rayovac 1 hr charger. Some people keep dumb timer based chargers around just for the purpose of zapping overdischarged cells up high enough to be recognized by smart chargers.


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## MarioJP (May 14, 2010)

It happened again (dammit lol) this time on another cell while being used in my usb charger, severely drained the cell. What I did this time is I left the cell to idle to see if the cell would recover by itself.

That's the weird part is that the cell did not recover on its own. I let it sit idle for 3-4 hours and took the measurement and the voltage is still at 0.46. Nimh cells would recover once idled. 

These ni-zn are just plain weird. I also noticed a pattern. When these cells are drained like that the voltage reading is always 0.46v and just floats there.

After that cell sat there for 3-4 hours and not recovering I did the trick again and when it got to 1 volt the cell started to recover on its own back to 1.3v. Drained it a bit to test the self recovery and voltage went back up on its own pretty quickly.

So what I am learning here about these cells is if you severely discharge them, you end up turning off the self recovery and would require to "jump start" the battery manually.

With NiMh this rarely happens even if left discharged for days. Voltage will eventually recover. Might take couple min or hours depending how long its been discharged.

Now to figure out way for this not to happen again lol.


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## core (May 15, 2010)

Mario, can I ask what the _other_ cells were at when that one got sucked dry? Were they above the knee?

I just had another incident myself, although nothing like yours. I had one at 1.28, one at 1.37V, and one up in the normal range still. 3 cell device, all 3 charged same day.

I keep saying this, and I know you guys get tired of hearing it, but that green light means freaking nothing. If you "always" charge your **** in perfectly balanced groups all the time it's not an issue at all, but otherwise this charger leads to problems. On the tail end of the discharge.

According to the manual, fully charged means 4 hours _after_ green light. I don't know if they're full of **** or not, they probably are, but definitely we can't start making 3rd party charts claiming any kind of credibility when the cells aren't charged in the first place.


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## Mr Happy (May 15, 2010)

core said:


> I just had another incident myself, although nothing like yours. I had one at 1.28, one at 1.37V, and one up in the normal range still. 3 cell device, all 3 charged same day.
> 
> I keep saying this, and I know you guys get tired of hearing it, but that green light means freaking nothing. If you "always" charge your **** in perfectly balanced groups all the time it's not an issue at all, but otherwise this charger leads to problems. On the tail end of the discharge.
> 
> According to the manual, fully charged means 4 hours _after_ green light. I don't know if they're full of **** or not, they probably are, but definitely we can't start making 3rd party charts claiming any kind of credibility when the cells aren't charged in the first place.



IMHO it's not to do with the green light or how long you leave the batteries in the charger after it comes on. These cells just have a lot of variation in capacity -- if you take any set at random they are almost certain not to be a matched and balanced group. This means that one cell will discharge long before the others.

Watch this thread where I will soon post some results concerning cell matching.


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## 45/70 (May 15, 2010)

Humm. Sounds like you're thinking more along the lines that the cells are not uniform, than just having been discharged/treated differently in your tests. That doesn't sound so good.

I wonder, and this is pure speculation, if UltraLast is getting second tier cells, as compared to PowerGenix? Doubtful, I guess.

Looking forward to your observations.

Dave


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## Mr Happy (May 15, 2010)

Capacity variation

Recall that for the first set of four cells under test I measured the following capacities (C9000, 500 mA discharge):

```
Cells 1-4 (mAh)
1365 1465 1370 1413
```
This is a variation of up to 100 mAh between cells, but as I had subjected different cells to different test cycles I was not sure if I had influenced the numbers.

For a second test I took a new set of cells and gave each of them exactly similar treatment. Here are the results:


```
Cells 5-8 (mAh)
 946  744  769  849  Factory charge from package
1427 1323 1369 1421  Cycle #1
1420 1333 1382 1424  Cycle #2
1437 1324 1401 1418  Cycle #3

1428 1327 1384 1421  Cycle average
```
There is again up to 100 mAh variation between the cells. In cycle #3 I rotated the cells to different charger slots in case different slots were charging differently, but this didn't seem to be the case. For each cycle I left the cells on charge long after the green light came on (sometimes overnight), but I don't have the impression that much further charging happens after the green light shows.

If you will use these cells, my suggestion would be to buy several and arrange them into balanced sets after testing them (a C9000 would come in handy). For instance of the cells I have I could make better balanced sets out of (2,4,5,8) and (1,3,6,7).


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## Mr Happy (May 15, 2010)

45/70 said:


> I wonder, and this is pure speculation, if UltraLast is getting second tier cells, as compared to PowerGenix?


That's an interesting thought. We would need someone to report on genuine PowerGenix brand cells to find out. Maybe the manufacturing tolerances are just not that good? Eneloops have set a very high benchmark for consistency these days.


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## Mr Happy (May 15, 2010)

Quick Charger

I monitored the charging voltage of the Quick Charger while charging a single empty cell.

The charger apparently does not use a true CC/CV algorithm, it uses a pulse charging method instead. Seemingly it applies short current pulses to the cell and then measures the resting voltage between pulses. Early in during the charge voltages as high as 2 V are applied to the cell and there is a big difference between the charging voltage and the resting voltage. Later on the pulses appear to become shorter and closer together, making it harder to separate the max and min voltages during a pulse. An oscilloscope would be helpful here but I don't have one.

The graph below shows my estimate of the cell voltage during charging in the off-current periods. This involved some interpolation of the data, so it may not be exactly right.

As can be seen, when the green light comes on the voltage drops sharply and continues to drop. I do not think any significant charging continues to happen during this period.







The red dashed line shows the maximum voltage I saw at the cell terminals, presumably corresponding to the "on" period of the current pulses. It leaves me curious as to exactly what algorithm the charger is applying.


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## HarryN (May 15, 2010)

Thanks for the info and testing Mr. Happy. Is it just me, or does that charging approach seem more similar to how you charge a Pb acid car battery?


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## core (May 15, 2010)

Thanks for your hard efforts and the detailed posts, My Happy! That's quite interesting there. You may make a believer out of me yet. And the physical design of the charger makes it a real bear to set up measurements, doesn't it?

If this is indeed the exact same charger as the PowerGenix, I find it quite interesting that they don't even use their _own_ recommended charging method. For better or worse -- I surely don't know.

Noticed you recommended the C9000 for discharge tests. Do you think it is wise discharging these all the way down to 0.90V repeatedly? The number 1.3V sticks in my head, although I'm not sure where I got that.


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## r1gm1n (May 15, 2010)

This is from the PowerGenix FAQ:

*Two Step Charge*


Temperature Compensated Voltage (TCV) = 1.90 - (0.003 x (T-25ºC) V/Cell
Constant Current 2A to TCV
Constant Voltage TCV to I < 90 mA
*Fault Conditions*




Stop Charge if the any of the following conditions occur:

Total charge time exceeds 2.5 hrs
Temperature of the cell rises by more than 15ºC
Temperature of the cell exceeds 40ºC
Voltage is less than 1.6V


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## Mr Happy (May 15, 2010)

HarryN said:


> Thanks for the info and testing Mr. Happy. Is it just me, or does that charging approach seem more similar to how you charge a Pb acid car battery?


I think you can charge any cell CC/CV if you know the exact parameters of the cell you are charging. For instance you could charge an Eneloop quite nicely using CC = 2.0 A, CV = 1.5 V. This depends on knowing all Eneloops behave the same way.

The reason CC/CV is not generally used for NiMH chemistry is because cells from different sources have different voltages due to variations in the exact formulation.

CC/CV can be used for these NiZn cells because they all come from the same factory and all behave in the same way.


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## Mr Happy (May 15, 2010)

r1gm1n said:


> This is from the PowerGenix FAQ:
> 
> *Two Step Charge*
> 
> ...


I think this is a case of "Do as I say, not as I do." Apparently the official charger for AA cells does not apply this charging method. (Unless the UltraLast charger happens to contain different electronics inside exactly the same case.)


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## MarioJP (May 16, 2010)

well this sucks. Looks like that one cell out of 8 that had the lowest voltage of 0.46V to whatever reason I can't figure how this happened will no longer hold a charge. It self discharge very fast.

After charging the cell at 1.9v. I let it sit for the next day. I take the readings and reads 1.3v.???. Furthermore I did a dead short and immediately free fall from 6A to 0.9A in 2 seconds. what gives.

Though the rest of the powergenix cells reads 1.86v so far. If these cells are this fragile I am sticking with eneloops lol.


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## Paul_in_Maryland (May 17, 2010)

My 12 NiZn AAs have performed consistently. They come off the charger at 1.65 to 1.7V. I apply a 1A load for 30 seconds, and the voltage under load drops to 1.59 to 1.66V. For some reason, I'm not seeing the 1.8V that other owners see. At least, not as reported by my MAHA C-9000 in discharge mode.


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## MarioJP (May 17, 2010)

Paul_in_Maryland said:


> My 12 NiZn AAs have performed consistently. They come off the charger at 1.65 to 1.7V. I apply a 1A load for 30 seconds, and the voltage under load drops to 1.59 to 1.66V. For some reason, I'm not seeing the 1.8V that other owners see. At least, not as reported by my MAHA C-9000 in discharge mode.



Sounds like the cells are not fully charged. They are suppose to come off the charger close to 1.9v


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## Mr Happy (May 17, 2010)

Paul_in_Maryland said:


> For some reason, I'm not seeing the 1.8V that other owners see.


Are you measuring them with a voltmeter? When they come off the charger I find they read 1.83 V +/- 0.01 V.


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## Navin_R_Johnson (May 17, 2010)

Mr Happy said:


> Capacity variation
> 
> Recall that for the first set of four cells under test I measured the following capacities (C9000, 500 mA discharge):
> 
> ...



There must be something I'm missing here. To me these numbers look fine. Was there something about NiZn as a technology or Ultralast as a company that would lead to a high expectation for uniform cell capacity? 

I'm going to assume you are benchmarking against Eneloops? If so, I fully agree that compared to Eneloops these fall just a little bit short as far as variation in cell capacity. But, Eneloops are really a top of the line cell based on a very mature chemistry. Compared to say my CTA 2700 NiMH AA's, these NiZn's look wonderfully consistent. Would it not be a more fair comparison to benchmark against multiple Ultralast AA NiMH cells? If Ultralast doesn't sell NiMH, would perhaps a Ray-o-Vac hybrid (good, but not top of the line cell) make a good basis for comparison?


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## Mr Happy (May 17, 2010)

Navin_R_Johnson said:


> There must be something I'm missing here. To me these numbers look fine.


This depends on how we define fine. Comparing to customary standards of the manufacturing industry is one thing. But what happens when a group of these cells is used in series, as with many applications? What we may find in that case is that one cell becomes completely discharged while the others still have a very high voltage, leading to reverse voltage applied across the depleted cell. In general nickel chemistry cells do not tolerate this and the reverse charged cell will be damaged. I think that given the higher operating voltage of these cells such an event is more likely to happen -- the low battery warning is less likely to occur with these cells than with NiMH.


----------



## Navin_R_Johnson (May 17, 2010)

Mr Happy said:


> This depends on how we define fine. Comparing to customary standards of the manufacturing industry is one thing. But what happens when a group of these cells is used in series, as with many applications? What we may find in that case is that one cell becomes completely discharged while the others still have a very high voltage, leading to reverse voltage applied across the depleted cell. In general nickel chemistry cells do not tolerate this and the reverse charged cell will be damaged. I think that given the higher operating voltage of these cells such an event is more likely to happen -- the low battery warning is less likely to occur with these cells than with NiMH.




I think what I was missing is your assumption that multicell applications have a low voltage warning or cutoff based on NiMH chemistry. I do understand the pitfalls of a multi-cell series configuration. The issue is not unique to NiZn though right? It can happen to NiMH cells if there is no warning or cutoff circuitry. Unless I'm not understanding your numbers, for any combination of your cells there would be less than 10% capacity left in any of the cells when the reverse charging occurs. Seems like any reverse charging would be pretty minimal, but I'm not really a battery expert.

I may not be properly interpreting your conclusion or statement either. In my opinion your data doesn't necessarily show a NiZn deficiency as far as uniform capacity between cells. NiMH cells can have just as high of variation, right? I would like to think that if a top manufacturer such as Sanyo were to start putting out NiZn cells those numbers would be a little tighter for their cells. Also as the chemistry becomes more familiar the numbers would likely get tighter for all the manufacturers.

I guess I was asking how you defined "not fine" and suggesting that "fine" be defined as comparing the capacity variation to a good NiMH cell, but not the Eneloop. I have some data for breakin on some of my NiMH cells I have purchased over the years. I have a Maha 9000 and ran the breakin cycle according to the specified capacity on the cell. This is not as good of data as what you did with the Ultralasts (multiple cycles, averages, changing charging slots, etc.) but it's something. Maybe you have some data on a good but not Eneloop NiMH cell? Maybe to satisfy my own curiosity I should devise an experiment to compare my Powergenix cells to my RadioShack cells. Suggestions and pointers would be appreciated.

8 cells of Eneloop - max 1971mAh min 1947mAh
16 cells of Radio Shack - max 1954mAh min 1866mAh
8 cells of CTA 2700 - max 1517mah min 766mAh

Eneloops are Eneloops and I'm sure you are very familiar with them. The Radio Shacks have been in use a couple years and still work just fine. I consider them good NiMH cells. 4 of the CTA's were sent to the recycle bin in less than a year and the other 4 get used in my kid's stuff. These are garbage. I am completely unfamiliar with Ultralast and have no idea where they would fit as far as a manufacturer.

I understand my data is not perfect and multiple cycles, averages, throw out high/low, etc. should be used, but if someone were to ask me how much the capacity varies amongst my Radio Shack cells, I'd tell them "Oh, they are all within about 100mAh of each other" which seems to be what you concluded for the Ultralast NiZn cells.


----------



## Mr Happy (May 17, 2010)

Navin_R_Johnson said:


> I may not be properly interpreting your conclusion or statement either. In my opinion your data doesn't necessarily show a NiZn deficiency as far as uniform capacity between cells.


I should have clarified this before, so let me clarify it now.

I do not see that I made any statement or drew any conclusion about the cells being deficient. I simply gave the results as I measured them and left conclusions to the reader. My use of "fine" and "not fine" was in response to your first use of the word.

I stated as fact that I discovered a variation in capacity between different samples of the cells. I later mentioned (again, as fact) that such variations can have an untoward outcome when groups of cells are used in series. The same can happen with other cells, and people hereabouts have gone to great lengths to form cells into balanced packs to mitigate any problems.

It seems perhaps you are reading more into my post than is actually there?


----------



## Paul_in_Maryland (May 17, 2010)

Mr Happy said:


> Are you measuring them with a voltmeter? When they come off the charger I find they read 1.83 V +/- 0.01 V.


No, I don't own a voltmeter. To get these readings (1.6 to 1.7V), I charge the NiZns overnight in the PowerGenix "1-hour" charger; stick them in my MAHA C-9000; set the MAHA to discharge them at 1000 mA; and look at the MAHA's LCD, one cell at a time, to read the voltage under this 1-amp load.


----------



## Mr Happy (May 17, 2010)

Paul_in_Maryland said:


> No, I don't own a voltmeter. To get these readings (1.6 to 1.7V), I charge the NiZns overnight in the PowerGenix "1-hour" charger; stick them in my MAHA C-9000; set the MAHA to discharge them at 1000 mA; and look at the MAHA's LCD, one cell at a time, to read the voltage under this 1-amp load.


To understand this, take a look at the discharge graphs in post #1. You will see that the voltage starts out above 1.8 V, but it drops almost immediately below 1.7 V as soon as the load is applied. This happens in seconds, much too quickly for the C9000 to show. To capture the "fresh off the charger" voltage, it must be measured using a voltmeter with no load at all.


----------



## Apollo Cree (May 18, 2010)

Paul_in_Maryland said:


> No, I don't own a voltmeter.



Spend $10 to $20 and buy at least a cheap voltmeter. Even a cheap one will be good enough to measure accurately enough to do what you need.


----------



## FlashPilot (May 18, 2010)

It will be interesting to see if this technology catches on in the future and how the batteries survive as they age and get cycled. With the sustained voltage during discharge, I cant think of any negatives for my flashlights.


----------



## MarioJP (May 18, 2010)

FlashPilot said:


> It will be interesting to see if this technology catches on in the future and how the batteries survive as they age and get cycled. With the sustained voltage during discharge, I cant think of any negatives for my flashlights.



I can think of one actually. These cells are not forgiving if they are overcharged or over discharged. after that they become paperweight. But other than that these are good cells for sustaining higher voltage.


----------



## Conan (May 18, 2010)

MarioJP said:


> I can think of one actually. These cells are not forgiving if they are overcharged or over discharged. after that they become paperweight. But other than that these are good cells for sustaining higher voltage.



It seems you're the only one with problems, didn't you charge them repeatedly in your BC 900 charger?


----------



## MarioJP (May 18, 2010)

I would have to say thath these cells last slightly longer than eneloops by merely 5%.

So how does a 1500mAh-1600mAh beats eneloop 2000mAh-2100mAH in my mobile usb charger?

I know this as the eneloops would charge my phone up from 8% to 85%. Same test with these cells ony my phone would be charged from 8% to 92%??

How is this possible??

I also figured out the problem and everything is all good lol.


----------



## Mr Happy (May 18, 2010)

MarioJP said:


> 1500mAh-1600mAh


I think that's a bit optimistic, actually. In my tests above I observed a range from 1350 mAh to 1450 mAh.


----------



## ampdude (May 18, 2010)

MarioJP said:


> I would have to say thath these cells last slightly longer than eneloops by merely 5%.
> 
> So how does a 1500mAh-1600mAh beats eneloop 2000mAh-2100mAH in my mobile usb charger?
> 
> ...



Well for one thing watt hours is a more accurate representation of the cell's capacity than amp hours when you are comparing different chemistries.


----------



## TakeTheActive (May 18, 2010)

ampdude said:


> Well for one thing *watt hours* is a more accurate representation of the cell's capacity than amp hours when you are comparing *different chemistries*.


Is it '*different chemistries*' or different voltages? :thinking:

Wouldn't a CAPACITY comparison between NiCd and NiMH be accurate?


----------



## Mr Happy (May 18, 2010)

TakeTheActive said:


> Wouldn't a CAPACITY comparison between NiCd and NiMH be accurate?


Not necessarily...for instance Eneloops have higher operating voltages than some other NiMH cells so they can deliver more energy than those other cells even when both have the same capacity.


----------



## 45/70 (May 18, 2010)

Mr Happy said:


> Not necessarily...for instance Eneloops have higher operating voltages than some other NiMH cells so they can deliver more energy than those other cells even when both have the same capacity.



OT, but this is also why 850mAh NiCd's could outperform the early 1200mAh NiMH cells under medium to high current loads. The voltage dropped so much more with the NiMH's that this resulted in the NiCd's of those days actually matching, or outperforming higher capacity NiMH's. You don't see any NiCd's anymore that are capable of this, unless you get a hold of some Cadnica's, or the like. Most consumer sized NiCd cells today seem to only work well at low current rates.

Dave


----------



## ampdude (May 18, 2010)

TakeTheActive said:


> Is it '*different chemistries*' or different voltages? :thinking:
> 
> Wouldn't a CAPACITY comparison between NiCd and NiMH be accurate?



Yes, thanks for the clarification. My statement could have easily been misinterpreted, I was indeed referring to the different voltages of NiMh and NiZn.


----------



## ampdude (May 18, 2010)

Mr Happy said:


> Not necessarily...for instance Eneloops have higher operating voltages than some other NiMH cells so they can deliver more energy than those other cells even when both have the same capacity.



But don't eneloops and other LSD to include hybrids have a slightly different chemistry than regular NiMh cells?


----------



## Mr Happy (May 18, 2010)

ampdude said:


> But don't eneloops and other LSD to include hybrids have a slightly different chemistry than regular NiMh cells?


Yes, but this is true in general across a whole variety of NiMH cells. Manufacturers have made various "tweaks" to the design and formulation so that it may be said that no two NiMH cells are alike in their chemistry. You can make an educated guess as to the original type of a given cell by close examination of the voltage on charging and discharging. This is a bit like a "fingerprint" for the cell.


----------



## TakeTheActive (May 18, 2010)

Mr Happy said:


> Not necessarily...for instance Eneloops have higher operating voltages than some other NiMH cells so they can deliver more energy than those other cells even when both have the same capacity.


IMO, you're getting 'too technical' here, i.e. comparing GOOD apples (1.2VDC under load) to BETTER apples (1.3VDC under load) when we're actually comparing apples (NiMh 1.2VDC under load) to oranges (NiZn 1.6VDC under load).

I know VERY little about Lithium-based cells but an example would be comparing a NiMh cell (1.2VDC, 2000mAh) to a Li-Ion (3.6VDC, 1000mAh - 'made-up' numbers both to make the calculations simple and since I don't have any Li-Ion specs memorized). In this case, although the NiMh has more CAPACITY (2 vs 1; amp-hours), the Li-Ion has more energy (2.4 vs 3.6; watt-hours).


----------



## Mr Happy (May 18, 2010)

I don't think I'm getting too technical. What really matters to people in the real world is the run time they get (or number of photos, number of flashes), and the quality of that run time (brightness of light, recharge time between flashes).

In a regulated light, camera or flashgun this depends mainly on the amount of energy stored in the battery and how effectively it can be delivered. In most cases higher voltage gives an advantage and capacity alone in mAh does not tell the whole story.

For instance the NiZn cells have an approximate energy of 1.6 V x 1400 mAh = 2250 mWh. This compares with Eneloops that are more like 1.2 V x 1900 mAh = 2300 mWh.

Where the NiZn have an advantage is in their instantaneous power delivery. They can supply 5 A while maintaining 1.5 V output voltage (mid-discharge) giving 7.5 W per cell. An Eneloop would maintain only about 1.1 V at 5 A, giving 5.5 W.

This extra "punch" from NiZn cells can in some cases be too much for devices to handle. Some flashguns for instance have failed under sustained use with such a strong power source.

To quote a saying, "it's all about the power".


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## TakeTheActive (May 18, 2010)

Mr Happy said:


> I don't think I'm getting too technical. What really matters to people in the real world is the run time they get (or number of photos, number of flashes), and the quality of that run time (brightness of light, recharge time between flashes)...
> 
> ...For instance the NiZn cells have an approximate energy of 1.6 V x 1400 mAh = 2250 mWh. This compares with Eneloops that are more like 1.2 V x 1900 mAh = 2300 mWh...


To clarify my previous statement:
When comparing cells of DIFFERENT CHEMISTRIES with DIFFERENT 'Under Load' VOLTAGES, watt-hour provides a better picture than amp-hour of energy available for use. (NiMh vs NiZn or NiMh vs Li-Ion)
.
When comparing cells of DIFFERENT CHEMISTRIES with SIMILAR 'Under Load' VOLTAGES, watt-hour provides a similar picture to amp-hour. (NiMh vs NiCd)
.
When comparing cells of the SAME (or very SIMILAR) CHEMISTRIES with SIMILAR 'Under Load' VOLTAGES, watt-hour provides a similar picture to amp-hour. (NiMh non-LSD vs NiMh LSD)
The point I'm trying to make is while 2000mAh is greater than 1400mAh (the consumer reading the label), 1.6VDC vs 1.2VDC evens things up (probably unknown to the average consumer).

If you want to talk Eneloop vs 'Other', ~1.25VDC x 2000mAh = ~2500mWh vs 1.2VDC x 2000mAh = 2400mWh (100mWh) is not as drastic a change as 1.6VDC x 2000mAh = 3200mWh vs 1.2VDC x 2000mAh = 2400mWh (800mWh).

This is for the folks that don't have V=IR, P=VI, etc... memorized.


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## Canuke (May 18, 2010)

45/70 said:


> I wonder, and this is pure speculation, if UltraLast is getting second tier cells, as compared to PowerGenix? Doubtful, I guess.



I wouldn't be surprised. Most of a 40-cell block of Ultralast alkalines I had leaked. I retired those cells with prejudice, and won't touch that brand again.


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## MarioJP (May 19, 2010)

Mr Happy said:


> I don't think I'm getting too technical. What really matters to people in the real world is the run time they get (or number of photos, number of flashes), and the quality of that run time (brightness of light, recharge time between flashes).
> 
> In a regulated light, camera or flashgun this depends mainly on the amount of energy stored in the battery and how effectively it can be delivered. In most cases higher voltage gives an advantage and capacity alone in mAh does not tell the whole story.
> 
> ...



So you are saying even though these cells has a slightly lower mAh rating but the higher voltage makes up those few mAh every bit of juice efficient??.

I guess the only downside to these cells is don't treat them as they were your emergency batteries. I doubt they would hold their charge for long. I call these cells "short term use only cells" But other than that you get a punch out of these cells. Though can't say for certain if your device will be K'O after that punch as in my experience with these cells is right off the charger voltage is 2V! wow.


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## ampdude (May 20, 2010)

TakeTheActive said:


> To clarify my previous statement:
> When comparing cells of DIFFERENT CHEMISTRIES with DIFFERENT 'Under Load' VOLTAGES, watt-hour provides a better picture than amp-hour of energy available for use. (NiMh vs NiZn or NiMh vs Li-Ion)
> .
> When comparing cells of DIFFERENT CHEMISTRIES with SIMILAR 'Under Load' VOLTAGES, watt-hour provides a similar picture to amp-hour. (NiMh vs NiCd)
> ...



Haha, great explanation. I think everyone who wants to compare the power of different cells should always have those basic formulas in mind, as they tell the real story. People are used to (mainstream) rechargeable cells (NiMh & NiCd) having the same voltage so people have become used to the whole amp hours rating as a true measure of power when it is NOT AT ALL!!!

Voltage = Current x Resistance and Power = Voltage x Current. I think :thinking:


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## HKJ (May 20, 2010)

ampdude said:


> Haha, great explanation. I think everyone who wants to compare the power of different cells should always have those basic formulas in mind, as they tell the real story. People are used to (mainstream) rechargeable cells (NiMh & NiCd) having the same voltage so people have become used to the whole amp hours rating as a true measure of power when it is NOT AT ALL!!!



But you must also be aware that for some flashlights it is the amp-hour that is relevant not the watt-hour (energy):


Flashlights with direct drive and maybe a series resistor will have shorter runtime with higher voltage, even for batteries with the same amp-hour.
Flashlights with a constant current driver (7135 driver chip), high voltage will make the light hotter, but give exactly the same runtime for the same amp-hour.
Flashlights with boost or buck drive will use the watt-hour rating.


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## Lynx_Arc (May 20, 2010)

HKJ said:


> But you must also be aware that for some flashlights it is the amp-hour that is relevant not the watt-hour (energy):
> 
> [*]Flashlights with boost or buck drive will use the watt-hour rating.
> [/LIST]


actually boost designs should run better with higher voltage as they are usually more efficient when the voltage doesn't have to be boosted as much while buck circuits are more efficient when the voltage input tends to be closer to the output of the circuit so the more voltage they have to convert to current the less efficient the output tends to be. It is possible that 2AA boost circuits may have problems with these cells as they can put more voltage out than what the boost circuits do. This can possibly cause the circuit to overdrive the LED beyond design or if the circuit design permits.... dropping into direct drive mode instead. 
These cells would probably be good for taking 2AA lights and direct driving low Vf emitters without boost circuits in them at slightly lower than full output. Perhaps instead of getting 200 lumens you would get 105 lumens direct driving a cree.


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## Mr Happy (May 20, 2010)

I did a test on a Fenix LD10 and the NiZn cell gave a somewhat brighter turbo mode than an Eneloop, but not as bright as a LiFePO4 cell.

I don't have the exact numbers to hand, but as I recall the relative numbers were about like this:

NiMH ........ 120 lm
NiZn ......... 150 lm
LiFePO4 .... 180 lm


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## 45/70 (May 20, 2010)

Mr Happy said:


> I did a test on a Fenix LD10 and the NiZn cell gave a somewhat brighter turbo mode than an Eneloop, but not as bright as a LiFePO4 cell.



Just curious Mr H, were you using one of the Westinghouse LiFe's, or from some other source? The reason I ask, is I seem to remember your observing that the Westinghouse LiFe cells didn't seem to hold up well at high current.

Dave


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## Mr Happy (May 20, 2010)

45/70 said:


> Just curious Mr H, were you using one of the Westinghouse LiFe's, or from some other source? The reason I ask, is I seem to remember your observing that the Westinghouse LiFe cells didn't seem to hold up well at high current.


Yes, the Westinghouse cells. I think they probably hold up as well at high current as any other LiFePO4 cell does. They shouldn't be compared with nanophosphate cells like A123 Systems as those are special.

According to my meter, the tailcap draw in turbo mode is as follows:

Eneloop .... 1.7 A
NiZn .......... 1.8 A
LiFePO4 .... 1.0 A

The Eneloop will give the longest run time, but the LiFePO4 is much the brightest.


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## core (May 27, 2010)

I made it a point today to examine two particular PowerGenix cells hot off the charger. 

Results: 1.71 and 1.74V
(This is rather low)

The reason I even bothered to look was because they were quite low coming out of the device. One much lower than the other, but both low.

They were placed in the charger in the middle two slots, no other cells in there at the time. They sat in there with a green light for many many hours.

I power cycled the charger and they have been actively charging (more) now for a half hour and counting.

I tell you, there is something up with this charger. It is getting to be a thorn in my side. (See previous posts) I'll give them the benefit of the doubt and say that the manual included with it was probably for an entirely different model which isn't on the market yet.


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## core (May 27, 2010)

Ok, mystery solved as far as I'm concerned.

After I popped those two cells back in the charger for more, they charged for what I estimated to be 70-80 minutes. That's as long as it usually takes to "charge" completely dead cells!

Cell temperatures peaked at 121F and 114F. I would have stopped it but I'm stubborn and wanted to see what would happen. They both started to cool down about 7-10 minutes _before_ the green light came on, for what it's worth. Ending voltage 1.85V on both.

It's quacking like a duck to me. Conclusion:

*The Quick Charger is a dumb timed charger* using who-knows-what for the pulsed charging algorithm. No independent channels, no nothing. 

This completely explains the uneven states of charge, and also explains why I frequently find myself with a seriously drained cell unexpectedly.

All that's left is for the fat lady to sing.


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## Mr Happy (May 27, 2010)

That's odd. I'm going to parallel the test with my charger. I have two cells: one fully charged and left for two weeks, resting voltage 1.804 V; one partially used and left for two weeks, resting voltage 1.778 V. I'll put them on the charger now (7:47 pm, middle two slots) and see what happens.


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## Mr Happy (May 27, 2010)

Update: the green light came on at 7:59 pm, indicating charge finished. Both cells are ice cold.

Cell voltages "hot" off the charger are 1.879 V and 1.875 V.

Perhaps your charger is defective?


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## Mr Happy (May 28, 2010)

It occurs to me to wonder about the low voltage on the cells. Due to the CC/CV algorithm they should charge up to 1.9 V before the charger will reduce current and switch off. If they are only reaching just over 1.7 V the charger will continue to apply full charging current until the back-up timer cuts in.

Did these cells charge successfully to begin with or have they always had such a low voltage? Can you associate this with any event in the cells' history, such as a large number of charge cycles, or perhaps a deep discharge?


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## core (May 28, 2010)

Thanks for giving that a go. And with chock full charged cells I get the same results.

After an overnight rest the two cells were 1.80 and... get this... 1.71V! Put them on the charger separately this time: The normal looking one took 6 minutes and the low one took (well it's still going.. I'm sure it will sit there and bake for 70+ minutes).

[Edit: It ended up charging for 120 minutes. Peak temperature 152F! That cell is now safe to eat according to USDA standards. Wow.]

Looking over my notes, the low one does in fact have a mildy interesting history. Looks like there were multiple occasions where I found it with 1.71V when it should have been charged. I chalked it up to not being fully charged at the time. (Silly assumption on my part!) All my cells have the same number of cycles as they have been kept in ordered rotaton. Less than 20 cycles total for each.

It has had at least two deep discharges. One down to 1.34V when I ran out of juice unexpectedly way early. And the real kicker is I discharged this on the BC-700 all the way down to 0.90V once. Just once. Worse yet, during that same discharge test I missed it switch into CHARGE mode so it got charged for a couple minutes. I doubt a few minutes of the BC-700's charge treatment would have destroyed it but that's the history of the thing.

So I seem to have a bad cell here, or maybe quite a few of them. There's definitely something up with this one of the pair.

However that doesn't explain why his counterpart (which seems to be good) only charged up to 1.74V the first time when they were in the charger together for the better part of the day. If they were truly independent channels that shouldn't have happened.

One thing that jumped out at me was you mentioned the back-up timer. I wonder if it's possible that the timer setting is not high enough to always charge fairly empty cells? Nah strike that, mine "usually" don't get low enough for that to matter.

Looks like the first thing I need to do is go through all my cells and find these "bad" ones. And then at least I may be able to find out why that effects the charging of other cells at the same time.


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## Conan (May 28, 2010)

My NiZn Pwergenix cells never get hot (not even warm) while in the charger.


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## MarioJP (May 28, 2010)

Ya if they get hot something is wrong.

I am doing a self discharge test I let them sit after 3 days and all 4 cells reads 1.86V

They should not get warm may a little but not close to getting hot.

This might be off this topic a bit but I am stuck on the MAh vs mWh thing. I just can't figure out how these cells beats the eneloops in run time???

I even went as far as had the phone drain down to 8% battery left, turned off the phone completely and let it charge until the eneloops were drained. Find out it only charges up to 83%

Same test with the Ni-Zn cells. These cells not only performed really well it actually topped my phone battery as the green light came on. Battery was at 100% when I turned my phone on.

so question I have if a D Cell battery has Higher mAh but voltage is 1.2v. Does the wattage stays the same??


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## alpg88 (May 28, 2010)

would nizn cells be suitable for a pack of 12 in series??


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## Mr Happy (May 28, 2010)

alpg88 said:


> would nizn cells be suitable for a pack of 12 in series??


Is your application suitable for an input voltage of 20 V or more?


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## alpg88 (May 28, 2010)

Mr Happy said:


> Is your application suitable for an input voltage of 20 V or more?


that is the idea.
12v 20-35w long life halogen bulb, via aw soft start


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## Mr Happy (May 28, 2010)

alpg88 said:


> that is the idea.
> 12v 20-35w long life halogen bulb, via aw soft start


Perhaps, but you might want to check the incan forum. I have read somewhere that massively over driving a 2000 hour ambient light bulb is less satisfactory than slightly over driving a 50 hour projector bulb. All the good hotwires are based on projector bulbs.


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## Bullzeyebill (May 28, 2010)

Mr Happy said:


> Perhaps, but you might want to check the incan forum. I have read somewhere that massively over driving a 2000 hour ambient light bulb is less satisfactory than slightly over driving a 50 hour projector bulb. All the good hotwires are based on projector bulbs.



Actually just the opposite. Many of the good hot wires are derived from 2000 hour bulbs. They re-rate very well. The 50 hr bulbs are already on the edge.

Bill


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## alpg88 (May 28, 2010)

Mr Happy said:


> Perhaps, but you might want to check the incan forum. I have read somewhere that massively over driving a 2000 hour ambient light bulb is less satisfactory than slightly over driving a 50 hour projector bulb. All the good hotwires are based on projector bulbs.


i already tried, it works, with 5x 18650, but 5 of those cells make too long of a light, worst case if i keep blowing bulbs, i'll just swap 1 cell for 1 dummy.
the reason i,m asking is that previously it was posted different capacity of 4 cells (if i understood correctly) from 1 pack, will this inconsistency hurt the cells in 12 cells pack? i will have to charge them out of the holder in special charger thou.


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## Mr Happy (May 28, 2010)

The inconsistency of capacity will only hurt them if you discharge them too much. You must avoid reverse polarization of any cells. I would calculate 75% run time and stop there.

For charging you will indeed have to charge them out of the pack, unless you can come up with a cell balancer designed for 1.9 V per cell.


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## Paul_in_Maryland (May 30, 2010)

*Re: "dumb charger" from UltraLast*



core said:


> Conclusion:
> 
> *The Quick Charger is a dumb timed charger* using who-knows-what for the pulsed charging algorithm. No independent channels, no nothing.


Are you positive that you mean the Quick Charger (the so-called 1-hour charger), and not the poorly (and deceptively) named Fast Charger (3 to 5 hours)? I use the Quick Charger--the white one. It's true that my cells never get warm and the voltage off the charge is on the low side (1.65 to 1.71V), even after the cells have been charging all night. But the Quick Charger uses four independent channels, letting you charge 1, 2, 3, or 4 cells at a time; that's a big reason I bought it.

But hey: If I can get another 0.1 to 0.2V per cell by using the black charger, I'd gladly give up the white cell's speed (which I never need) and independent channels.


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## Bapman (May 30, 2010)

Beyond the upcoming second generation(hope better consistency)of NiZn cells,is there information of a new (better) charger too?

Ben.


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## core (May 30, 2010)

*Re: "dumb charger" from UltraLast*



Paul_in_Maryland said:


> Are you positive that you mean the Quick Charger (the so-called 1-hour charger), and not the poorly (and deceptively) named Fast Charger (3 to 5 hours)? I use the Quick Charger--the white one. It's true that my cells never get warm and the voltage off the charge is on the low side (1.65 to 1.71V), even after the cells have been charging all night. But the Quick Charger uses four independent channels, letting you charge 1, 2, 3, or 4 cells at a time; that's a big reason I bought it.



Yes, I have the white 1-hour charger which charges 1-4 cells. At the start of the charge it blinks at you to tell you how many cells it recognized. Model #F100011-14. And I'd just like to add that when I accused it of being a dumb timed charger, it seems it was actually a damaged cell causing it to act like a timed charger.

1.65V is _far_ too low right off the charger. I'd guess you also have at least one wrecked cell which is causing that. Sounds like you are in the habit of leaving your cells in the charger for extended periods of time after the green light comes on? I used to do this too, because the silly manual basically said to do so.

But what I think may be going on is the bad cell (or cells) is somehow equalizing with the good ones while they sit on the charger, causing all of them to lose charge. Mr Happy's test seemed to show that leaving it on the charger has no benefit anyway. So from now on I try to remove my cells as soon as they are done charging. And obviously isolate those damaged cells. The "One bad apple..." saying appears to be very true here.


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## Paul_in_Maryland (May 30, 2010)

If my charger is underperforming, or my cells are bad, that's great news. It means that once I've figured out what's wrong, I can look forward to cells of higher voltage.

What the heck: The black charger is so darn cheap, I may buy one, perhaps bundled with another eight NiZns.


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## MarioJP (May 30, 2010)

Bapman said:


> Beyond the upcoming second generation(hope better consistency)of NiZn cells,is there information of a new (better) charger too?
> 
> Ben.



Higher capacity maybe? Are we going to see AAA of these cells ??


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## 357mag1 (May 30, 2010)

*Re: "dumb charger" from UltraLast*



Paul_in_Maryland said:


> Are you positive that you mean the Quick Charger (the so-called 1-hour charger), and not the poorly (and deceptively) named Fast Charger (3 to 5 hours)? I use the Quick Charger--the white one. It's true that my cells never get warm and the voltage off the charge is on the low side (1.65 to 1.71V), even after the cells have been charging all night. But the Quick Charger uses four independent channels, letting you charge 1, 2, 3, or 4 cells at a time; that's a big reason I bought it.
> 
> But hey: If I can get another 0.1 to 0.2V per cell by using the black charger, I'd gladly give up the white cell's speed (which I never need) and independent channels.



Paul,

I find it interesting that your white charger only charges your batteries to 1.65-1.71. It makes me wonder if you have a defective unit.

I own two of the white chargers and the batteries come off at 1.92 if you grab them as soon as they finish. I just put some in both chargers to verify this again. The batteries then drop to 1.830 -1.840 in 24 hours. They settle out at 1.820 and seem to stay there for at least a week.

This is as measured with a Fluke 87.

Scott.


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## lemlux (Jun 9, 2010)

My Ultralast Green charger yields cells that read 1.83V ti 1.84V on my old multimeter which I suspect may typically read as much as 0.10 V high.

I usually try to avoid putting more than a 1.8A load on AA rechargeables and, therefore run my version of the 9.6V 3.15 A Mag85 in either a fivemega 6aa fat body loaded with a 9s2p to 3 dcell long battery pack or a single length 3*18650 pack.. This 18aa cell pack is quite heavy.

I'm happy to report that using a single 6aa to 1D cell fm battery holder with 6 of the ultralast Ni-Zn cells drives a WA 1318-U bulb rated at 9.6V 1.93A 534 Lu 35 Hours beautifully. This body / cell configuration had previously been limited to 6V 1.7 A bulbs that generated half the lumens. (I run WA1111's in five mega's 6s2p 2 d cell tall adapter in another of his wide bodies.)

The 6 * Ni-Zi with WA 1318 combination should, thus, work well in currently available Mag 2D's with currently available 3aa to 2d adapters.


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## Mr Happy (Jun 9, 2010)

lemlux said:


> My Ultralast Green charger yields cells that read 1.83V ti 1.84V on my old multimeter which I suspect may typically read as much as 0.10 V high.


I think 1.83 to 1.84 V is about right. Those are the readings I get on various meters with my charger.


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## 45/70 (Jun 10, 2010)

Mr H, a question. You didn't think it was a good idea to charge these NiZn cells in series. Perhaps the one charger that seems to charge cells in series does have some phantom firmware to allow this. My question is, in your opinion, could these cells be charged in parallel? I'm about to order 8 of these cells, but _*I refuse to buy yet another charger!*_ The chargers that are offered don't impress me and besides that, I already have almost as many chargers as I do cells! Well, not really but.....

Dave


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## Mr Happy (Jun 10, 2010)

It should be OK to charge these cells in parallel.

From the tests above, I think the Quick 1 hr charger already does this. When you charge a set of cells in parallel you should still use the recommended CC/CV algorithm (except you can perhaps increase the CC current in proportion to the number of cells). If you do charge in parallel you should make sure all cells are in a similar condition and similar state of charge.

You _could _charge the cells in series as long as you provided a proper balancing setup and still used the CC/CV algorithm. However, I don't think there is a 1.9 V cell balancing system readily available so this option is more theoretical than practical.


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## 45/70 (Jun 10, 2010)

Thanks, Mr H



Mr Happy said:


> When you charge a set of cells in parallel you should still use the recommended CC/CV algorithm.



Yeah, I'll be using my bench PS, so the eyeball/brain part of the algorithm will be the weakest part. The only problem I foresee, is that it may be a bit slower than the 1 hr charger, charging 4 cells, as it only has 3A capability. After the initial "testing/wowee this is cool stage", my intended applications for these cells will not require charging very often so, not really a problem

I may still try the hobby charger idea, without balancing. You pretty much convinced me that it won't work properly, but if I can set it up so as to monitor just two cells in series, closely during charge, I may still give it a go. It wouldn't really be any better than charging in parallel, but may be interesting.

Dave


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## bigchelis (Jun 11, 2010)

I really am starting to dig these new Ni-Zn AA cells. I wish they came in C and D size.


I have a Milky L1 Extreme: R2 direct drive off whatever cells are in the hosts.

The Ni-Zn did really well and way better then I expected.


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## r1gm1n (Jun 11, 2010)

bigchelis said:


> I really am starting to dig these new Ni-Zn AA cells. I wish they came in C and D size.


I use 4 of my NiZn is the Eneloop D adapters for a lantern and they work okay. Somebody even makes a nesting AA into a C adapter into a D adapter. YMMV !


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## 45/70 (Jun 18, 2010)

Yesterday, I received 8 PowerGenix AA cells. As info, the voltages as received, were 1.57-1.66 volts. I did not discharge them on my Maha C9000, but did charge them 4 at a time in parallel, CC/CV (2A/1.9V) on my bench PS.

If I discharge them on the C9000, what is the voltage at which the discharge should be stopped? I looked through this thread and some other places, but I couldn't find anything. I know I've seen it somewhere and, as I remember, they should definitively not be discharged to 0.90 Volt! So, what is the minimum acceptable voltage under load for a NiZn cell, and also the minimum acceptable OC voltage for these cells?

I'd really rather use my CBA II, but the only computer I have at the moment is 64bit XP, and I can't use the software.  It'd take forever, as I could only discharge one cell at a time but......

Dave


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## Mr Happy (Jun 18, 2010)

I have discharged mine on my C9000 for testing and I honestly don't think it will hurt the cells at all. I was more concerned about blowing up the C9000 circuits by feeding them more voltage than they were accustomed to! To play it safe I only discharged at 500 mA and did not risk 1000 mA.


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## 45/70 (Jun 18, 2010)

OK, thanks Mr H. I had noticed that the graph in your first post stopped at 1.2 Volts. I was just wondering if that was the "magic" number. I'm sure I read somewhere that NiZn cells don't like to be discharged below a certain voltage, but then again, maybe I didn't. 

I hadn't really thought about overloading the c9000's circuitry. Now you've got me thinking I should look around here for a 32bit computer that can be slapped together without too much trouble, and just use the CBA II. :thinking: I would probably stop discharge midway through the "hump", if I go that route.

Thanks again,

Dave


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## MarioJP (Jun 18, 2010)

Discharging these cells below 1.3v will not hurt them?. Isn't it the magic number to stop the discharge at 1.3v??


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## core (Jun 18, 2010)

45/70, I don't know what the magic number is, as I didn't have the guts to repeat my previous testing with my new replacement cells that arrived last week, but...

Please be sure to update this thread with your findings. 

Four of mine have developed what I can only describe as a moderate resistance internal short, after doing such things to them. They will drain themselves down to a flat 0.00V after sitting for a week.

At least you charged yours first already. (I did not.) So you may be safe.


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## Mr Happy (Jun 18, 2010)

I cut off the discharge graphs at 1.2 V in the first post because the slope is pretty steep by then and I wanted to make the graph look better by making best use of the scale.

When I discharge the cells in the C9000 they get down to 0.9 V in a matter of seconds after reaching 1.2 V and then the voltage rebounds quickly after the C9000 terminates. I've done it a few times and the C9000 does not seem to get warm or anything. I think it's OK.

I do not know of any reason why a NiZn cell will be harmed by discharging to low voltage. That's not to say there is no reason, but I have not seen any problems with my cells after discharging that way.


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## MarioJP (Jun 18, 2010)

core said:


> 45/70, I don't know what the magic number is, as I didn't have the guts to repeat my previous testing with my new replacement cells that arrived last week, but...
> 
> Please be sure to update this thread with your findings.
> 
> ...



Now that is interesting, what did you do to them for these four cells to develop such a condition?.


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## core (Jun 18, 2010)

MarioJP said:


> Now that is interesting, what did you do to them for these four cells to develop such a condition?.



These are the same cells that I've been posting details about as time went on so I won't repost the complete story, but the short answer is:

I discharged them to 1.20V (some 0.90V) straight out of the package without charging them first. Then continued using them normally over the next month or two and missed little clues that things were going south with them. 

Next 8pk I buy, I will donate them to the cause and put half of them through similar treatment to see.


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## MarioJP (Jun 18, 2010)

I started to notice that with one of the cells. Before i started using them I labeled each cell with a number so I can identify which cell is which in case they were going south.

The good news they performed well in my usb mobile charger. Downside is one out of four which is cell #4 got discharged to 0.64v. Ever since that incident. Charging on this cell is not the same. One thing i noticed is this cell would get warmer faster than the other ones. So decided to do some tests on this cell, I noticed that this cell lost 10% of its original capacity.

Now I am very cautious of how far the discharge goes. My usb mobile charger has 3 LED indicator to tell me how much power the cells have, however i don't think the indicator is design for Ni-Zn cells.

What would happen is all 3 LED's are lit up from start to end. And when they go out all 3 goes out instantly without warning. By that time the cells would be severely discharged. What I don't understand is the first 3 cells recovered to 1.3v and up. while cell 4 took a little longer. Eventually did recoverd, just longer.

Now I just need to time it properly. Otherwise they be ruined if this keeps up and go back using the eneloops.


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## Mr Happy (Jun 18, 2010)

While I doubt that deep discharge will hurt these cells very much, I do imagine that reverse charging and polarity reversal will be a problem. Given the fairly uneven capacity measurements I have seen within batches of cells I think the probability of a cell being reverse charged is quite high when cells are used in a multi-cell application.


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## lemlux (Jun 18, 2010)

I recently read a post by fivemega where he says that he draws 4.5 Amps on a direct drive nailbender SST-90 drop-in driven by 3 @ Ni_Zn AA's. That's impressive.


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## MarioJP (Jun 18, 2010)

just how uneven does it take for the reversal to happen?


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## core (Jun 18, 2010)

Wouldn't a cell have to get lower than Mario's 0.64V before anything like that started to happen? And the device would still have to be drawing power?

I know for certain mine never got drawn below 0.90V.


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## MarioJP (Jun 18, 2010)

core said:


> Wouldn't a cell have to get lower than Mario's 0.64V before anything like that started to happen? And the device would still have to be drawing power?
> 
> I know for certain mine never got drawn below 0.90V.



Plus my Multimeter would of displayed a black line indicating the polarity have reversed which it did not.


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## core (Jun 18, 2010)

MarioJP said:


> Plus my Multimeter would of displayed a black line indicating the polarity have reversed which it did not.



Well I mean depending on how long it rested before you got your meter on it, it could have recovered some. 

I was under the impression though that a cell had to be down to zero, under load, before reverse charging would take place. Usual scenario for me is "hrmm, my device is starting to be sluggish" and I put a meter on it immediately, then it's like "oh [email protected], 1.21V". I would sure notice it if one cell wasn't contributing much of anything.


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## MarioJP (Jun 18, 2010)

well its hard to tell because the other 3 cells were at the end of charge. did a discharge on those 3 cells to confirm and did not last too long. Stopped at 1.3v. I don't know what really did happened to that cell, but the idle voltage on cell 4 was 0.64v. could be the possibility cell 4 going into polarity reversal during load for a short period and recovered after I turned off the usb charger??.

My next test is I am going to let these cells sit and see what happens. To answer your question to how long the cell rested after I took them out. I took the readings the moment I turned the usb charger off and took the cells out. Cell 4 was at 0.64v. Other 3 were at 1.3 to 1.4 (I am guessing the voltage on those 3 cells were bouncing back up quickly)


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## Mr Happy (Jun 18, 2010)

MarioJP said:


> just how uneven does it take for the reversal to happen?





core said:


> Wouldn't a cell have to get lower than Mario's 0.64V before anything like that started to happen? And the device would still have to be drawing power?
> 
> I know for certain mine never got drawn below 0.90V.





MarioJP said:


> Plus my Multimeter would of displayed a black line indicating the polarity have reversed which it did not.





core said:


> Well I mean depending on how long it rested before you got your meter on it, it could have recovered some.
> 
> I was under the impression though that a cell had to be down to zero, under load, before reverse charging would take place. Usual scenario for me is "hrmm, my device is starting to be sluggish" and I put a meter on it immediately, then it's like "oh [email protected], 1.21V". I would sure notice it if one cell wasn't contributing much of anything.



"Down to zero, under load" is exactly it. Take a look at my discharge graphs in post #1. Observe that the green line is almost vertical at 1.2 V, where the discharged capacity is about 1300 mAh. Since the line is vertical, the cell is "down to zero" at 1.2 V. If you tried to draw another 10 mAh from the cell, say, taking it to 1310 mAh, then the voltage would go below zero (extend the green line and see what I mean). It only takes one or more stronger cells in the circuit to make this happen.

You will never see this after you remove the cells from the circuit. You would have to measure the voltage across each of the cells while installed in the device and under load to see it happen. Most cells are damaged by this, including Eneloops. If you have a device with two, three or four cells in series, you really need to stop well before you think the batteries are discharged, or you risk damage.

If you want a visual analogy, think of a small car with a top speed of 80 mph being pushed by a big muscle car with a top speed of 150 mph. The big muscle car can easily push the little car up to 100 mph with its engine whizzing, but under these circumstances the little car is being "reverse charged" in spite of doing 100 mph. Maybe its cams will be damaged, maybe its bearings will overheat. An empty battery in a series circuit is just like that little car. It is being tortured.


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## MarioJP (Jun 18, 2010)

Mr Happy said:


> It's true, I've not seen the green light flash either. As far as I can tell, the red light goes out and the green light comes one.
> 
> For my discharge test in post #1 the cell was removed soon after the green light came on. I didn't time it exactly, but it would have been after 1.5 hours and less than 2 hours. I will look more closely into this now I'm starting to get the picture.



Oh wow thanks for that info. That just gave me clue of whats going on.

My usb charger with these cells draw close to 600mA and the duration of it is 2 hours. I was able to connect the meter across the first 2 cells, which is another thing I do not quite get about this usb charger is how the cells are actually connected. It looks like its in pairs of 2 out of 4 total because slot 3 and 4 are facing the same direction or ++ top --bottom on 3 and 4. So I assuming 600mA per pair??


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## core (Jun 18, 2010)

Mr Happy said:


> Observe that the green line is almost vertical at 1.2 V, where the discharged capacity is about 1300 mAh. Since the line is vertical, the cell is "down to zero" at 1.2 V. If you tried to draw another 10 mAh from the cell, say, taking it to 1310 mAh, then the voltage would go below zero (extend the green line and see what I mean).



Thanks. I think this simple concept was what was tripping me up. As vertical as that is, there really isn't much wiggle room there.

Wish I had taken the time to put load on these the few times that I noticed they were a "bit" too low. Before charging them back up I mean. Can't say for sure one way or another whether any of these were even close. Ok I know _one_ of them was for sure.


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## MarioJP (Jun 21, 2010)

Well I used these cells again in my usb mobile charger, and one thing I noticed while in use. The cells got hot almost to burning hot during discharging. I was this close of turning it off and letting the cells cool. What is up with that??


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## filibuster (Jun 22, 2010)

Has anyone had any experience with these cells in cold temperatures?
The PowerGenix website (http://www.powergenix.com/technology-comparison.php) states that these cells should be good to -20C (-4F) which would be an advantage over NiMH. Currently lithium primary cells are the only long runtime option for cold weather AA battery use. NiCad works but the capacity isn't there.


On some of the charging issues mentioned earlier in this thread. I found in another post from a different thread this comment which maybe helpful:



> Nickel-Zinc is a very old and well known battery chemistry, so is their charging parameters. Before Powergenix batteries, Nickel-Zinc chemistry never made to the mass market because of their very limited number of cycles, caused from some unappropriate properties of the zinc.
> The problem I see with Powergenix battery is that, unlike Ni-CD and Ni-MH, there is no mechanism to recombine hydrogen and oxygen which produces at end of charge.
> This is the reason why the battery cannot be overcharged or trickle charged, and charge has to be terminated when the idle currrent falls below 90 mA, and the series packs needs charge balancing. Overcharge will cause a leakage.
> 
> ...


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## hank (Jul 20, 2010)

Yeek. Seems like the 1-hour and 5-hour chargers bundled with the NiZn batteries are different.
From their FAQ:

PowerGenix offers two different charges (they mean "chargers") -- the "Quick" and the "Fast"
hmmmm .... looks like the "Quick" might be slightly smarter?

---- quote follows----

The PowerGenix Quick charger recharges anywhere from 1 to 4 AAs at a time. It takes approximately 1-½ hours to fully charge 1 to 2 AA batteries, and about 2 ½ hours to charge 3 to 4 of the batteries at one time. The Quick charger is equipped with special features such as temperature sensors to prevent batteries from overheating damage, reverse polarity protection and bad battery sensors.

The PowerGenix Fast charger recharges either 2 or 4 AA’s at a time. It takes approximately 3 hours to charge 2 AA batteries and about 5 hours to charge 4 AA batteries. The Fast Charger is equipped with a smart channels feature, which prevents charging if batteries are inserted incorrectly. 

----end quote----

Is there a known good 'balancing' charger, or single-cell or separate-channel charger, that works with these NiZn cells?


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## Mr Happy (Jul 20, 2010)

hank said:


> Yeek...


I don't get what you are asking.

Of course the 1 hr and 5 hr chargers are different -- they are different chargers.

Is there some reason you don't think the 1 hr charger is a good charger?


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## hank (Jul 20, 2010)

> is there some reason you don't think

No opinion on either one, that's why I'm asking; the FAQ says they're different but not much detail, at the original source. But I don't know if the chargers from the 3rd-party suppliers are identical. Cost-cutting on chargers is hard to detect.

They mention having an overheating sensor on the "1-hour" --- that's one difference.

One handles one to four cells; the other handles pairs, two or four cells. 

I'm hoping for more about NiZn chemistry and whether either of these chargers --- or some other method -- looks right for best lifetime of the cells before they die.

It's, in my experience, been easy to kill batteries with cheap chargers. For a new chemistry, I figure, start by understanding the charging process. So I'm asking.


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## Mr Happy (Jul 20, 2010)

There is only one NiZn rechargeable system on the market, which is the one from PowerGenix. To the best of anyone's knowledge, NiZn cells and chargers from other sources (such as in this thread) are the same PowerGenix items rebranded.

Due to its individual cell charging capability and shorter charging time I feel the 1 hr charger is the best option.

The recommended CC/CV charging protocol for the cells is described in exquisite detail in the information on the PowerGenix web site.

From experiences reported so far, the cells seem somewhat fragile and are not likely to last as long as NiMH cells like eneloops. Furthermore, mistreatment can cause early failure.

In summary, the NiZn cells fill a niche for applications needing higher voltages. Try them if you have a specific need, but they are not going to replace NiMH in general applications any time soon.


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## Paul_in_Maryland (Jul 21, 2010)

lemlux said:


> I recently read a post by fivemega where he says that he draws 4.5 Amps on a direct drive nailbender SST-90 drop-in driven by 3 @ Ni_Zn AA's. That's impressive.


FiveMega is bullish on NiZn's future. I wrote to him, urging him to make more 3xAA bodies and even some 4xAAs. He replied that NiZn AAs will make those configurations largely unnecessary.


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## funkychateau (Oct 5, 2010)

Saw these cells cheap in the "good deals" section, so I'm reviewing old threads before making the decision to buy or not.

The high-but-dropping "peak charging voltage" is possibly due to the decrease of internal resistance as the cell charges. 

For a constant-current charging pulse, the peak voltage would be highest when internal resistance is highest, provided that the voltage drop across that internal resistance is more significant than the lower Thevenin voltage in that discharged state.

Unfortunately, the charge seems to terminate when the "resting" voltage between pulses hits the 1.9-V threshold. Makes me wonder if the cells are being fully (and equally) charged, because they spend no time in the CV domain with current tapering.

I guess one way to test if they are fully charged would be to take them immediately out of the supplied charger when the light goes green, apply exactly 1.9 volts from a lab supply, and measure the current drawn. If it's down in the 50-75 ma range, then the cell was already fully charged. If it's substantially higher, then the cell was undercharged.

I'll do this if I buy some of these cells.



Mr Happy said:


> Quick Charger
> 
> I monitored the charging voltage of the Quick Charger while charging a single empty cell.
> 
> ...


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## Mr Happy (Oct 5, 2010)

funkychateau said:


> The high-but-dropping "peak charging voltage" is possibly due to the decrease of internal resistance as the cell charges.


Another possibility is that my meter does not have a short enough sample interval to capture fast changing voltages. The meter has a sample rate of about 4/sec, but I don't know how long it takes to lock in on each reading.

If I ever get an oscilloscope (new toy! ) I will surely revisit this. Likewise if I happen to get a lab power supply...


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