Are there any "real" 2700 mAH NiMH AA batteries?

[Closet_Flashaholic]

Of 20 Powerex 2700 NiMH batteries, 0% still meet specification of 2700 mAH rating.

The maximum number of cycles on any one battery is < 20. The capacities range from 2190 mAH to 2530 mAH as measured with C9000 (early revision, don't remember which one). All batteries were broken in and then maintained with the C9000. Batteries were not abused, but were used.

So, CPF members, I put the question to you:

(Original question's wording is now changed)

New Wording:
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Has anyone used NiMH AA batteries that can sustain a measured 500 mAH discharge rate for at least 5.4 hours (+/- 5%) over the course of 20 or more cycles?

I am not really interested in specifications at this point. Real world experiences only, please.
-------------------------

Original Wording:
Are there any NiMH AA batteries with a 2700mAH or greater spec. that you have personal experience with that maintain their capacity over time and at least 100 cycles (being generous to the manufacturers with this)?
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This kind of makes me wonder if rechargeable batteries also need a minimum cycle specification that holds the capacity since all 20 batteries did meet spec during break-in and it was all "down hill" after that. Similiar to the BS Energizer 2500 fiasco that occurred a few years ago, but not as dramatic. The Powerex cells at least still hold their charge, even if it's substantially less.

 

[jch79]

Sanyo Industrial 2700mAh

I dunno how many times I've charged mine, but they're holding up like champs. :shrug:

:thumbsup: john

 

[325addict]

Varta professional 2700mAh.

With my very simple constant-current charger, I realized more than 2500mAh on ALL of them.

They will last for years I think, as I always charge them gently. ALL of those hobby-chargers push them that hard, that they'll get too hot! Remember, above 40 degrees Centigrade they WILL be damaged!

Regardless what others here will say, I stay with my slow charging with 1/10C for about 15 hours. This has proved the best way to virtually endless battery-life....


Timmo.

 

[tabetha]

I always charge at the slowest setting possible, on my BC700 and 900.
I have some ANSMANN AA's that consistently on each charger give around 3400mah, performance seems to back this up, they do last noticeably longer.
I use 99% Uniross Hybrio's, rated at 2100mah, most come out at around 2400-2600, the non hybrio uniross around 2600-2700.
tabetha

 

[TONY M]

I always charge at the slowest setting possible, on my BC700 and 900.
I have some ANSMANN AA's that consistently on each charger give around 3400mah, performance seems to back this up, they do last noticeably longer.
I use 99% Uniross Hybrio's, rated at 2100mah, most come out at around 2400-2600, the non hybrio uniross around 2600-2700.
tabetha

I haven't been keeping a track of it but my Uniross Hybrios (identical to eneloops) did not greatly exceed their stated capacity if at all.
I also have the 2100mah Uniross batteries and they also came in at around 2100mah at 400mA discharge on the Maha C9000. I srongly suspect that your charger is overestimating the batteries capacity.

 

[Mr Happy]

I always charge at the slowest setting possible, on my BC700 and 900.
I have some ANSMANN AA's that consistently on each charger give around 3400mah, performance seems to back this up, they do last noticeably longer.
I use 99% Uniross Hybrio's, rated at 2100mah, most come out at around 2400-2600, the non hybrio uniross around 2600-2700.

I think it has been explained to you before that the numbers you are quoting are not the capacity of the battery? The numbers you give are the amount of charge fed into the battery during charging. Since the numbers are so large, it means the charger is overcharging the batteries. In the short term this may do no harm, but in the longer term it may wear out the batteries prematurely.

To find the actual capacity of the batteries use the Test mode.

To treat your batteries more kindly, consider charging them at 1000 mA rather than 200 mA.

 

[tabetha]

It was explained to me sorry, I did overlook this unfortunately, not intentionally, my memory is that bad, owing to brain damage.
To satisfy my curiosity, and to ensure more accuracy from myself I take on board what you have said, I have just put my BC 700 into "charge test" mode on 2 X Uniross Hybrio's, and 2 X Ansmann cells in AA format.
tabetha

 

[LoM]

This will sound weirdo to say the least but, have tested many batteries with my BC 700 and most of them are quite below advertised capacity (Duracel, Uniross, etc - dont remember all).

The biggest exception are iKea brand. I bough something like 16 of those between summer 2007 and summer 2008. It were all advertised as 2050 mah (or something like that) BUT none of them was lower then 2400 mah. After a few months of use (lets say 20/30 cicles each) the lower reading I have is 2300.

Now the surprise, two bateries were around 2800 at first cicles and remain very high around 2700. I use these bateries mostly with my GPS (1 pair for caching day, 100 caching days a year ) How is is possible

 

[clintb]

This will sound weirdo to say the least but, have tested many batteries with my BC 700 and most of them are quite below advertised capacity (Duracel, Uniross, etc - dont remember all).

The biggest exception are iKea brand. I bough something like 16 of those between summer 2007 and summer 2008. It were all advertised as 2050 mah (or something like that) BUT none of them was lower then 2400 mah. After a few months of use (lets say 20/30 cicles each) the lower reading I have is 2300.

Now the surprise, two bateries were around 2800 at first cicles and remain very high around 2700. I use these bateries mostly with my GPS (1 pair for caching day, 100 caching days a year ) How is is possible

Are you, perhaps, seeing those higher than rated numbers during a CHARGE mode? If so, the amount of energy put in, when the cell is depleted, will almost always be equal to, or greater, than the rated capacity. That's assuming the rated capacity is actually correct, and not a mis-label.

See Mr Happy's post above. You need to make sure you're reporting the rating from a DISCHARGE.

 

[Closet_Flashaholic]

So, after a couple of days' worth of feedback from everyone, I am coming to the conclusion that the answer to my question is "No, there are no 2700 mAH AA batteries that actually deliver to spec over a period of time". This is good to know, because I am not wasting any more money on them. I will stick to eneloops I guess and just have to change them more often. At least I seem to be getting an honest and consistent mAH rating from them.

Thanks everyone, I just wish someone had had a better experience.

 

[MattK]

Our Titanium 2700mah AA's consistently deliver 2650+ when tested on our Cadex 7400 Analyzer.

 

[bobrip]

Describing battery performance is very complex. You must take into consideration the temperature, number of charge/discharge cycles on the battery, how it was charged, what was the discharge current, what was the cutoff voltage during discharge, etc. Most people want a simple answer and with batteries there are none. Edison said "Whenever you are talking about batteries you are lying". To me this means that the behavior is so complex that you cannot really describe it.

 

[tabetha]

Just to add confusion here, 2 of my AA cells are finished in the charge test mode.
A ANSMANN battery previously mistakenly by myself believed to be around 3400, has finished with a reading on 000, a Uniross Hybrio has finished with a 2.03ah, ie 2030mah, rated as 2100 mah so close enough, the ansmann is rated as 2600mah, it works etc etc quite well, but returns a 000 reading ?
So even more confused now, just waiting for 1 more ansmann, and I hybrio to finish cooking now.
Would I be right in thinking the 000 reading indicates a dud cell, that is not of much use comparably to others ?
tabetha

 

[LoM]

Are you, perhaps, seeing those higher than rated numbers during a CHARGE mode? If so, the amount of energy put in, when the cell is depleted, will almost always be equal to, or greater, than the rated capacity. That's assuming the rated capacity is actually correct, and not a mis-label.

See Mr Happy's post above. You need to make sure you're reporting the rating from a DISCHARGE.

Those are reporting numbers from Discharge cicles.
One of the reasons I bought the digital charger was because the iKea cells were lasting longer than branded cells with higher advertised capacity on my GPS.

I was getting +1 day of geocaching with iKea cells and sometimes less than 1 day with other cells (the ones sold at Lidl advertise 2500mah and none of the 8 I sent to the garbage had readings above 1500mah, even after breaking them with the refresh function).

After testing them all understood why. Dont know if it was just luck

Now Im waiting for some Vapex 2900mah to see what I will get. In a caching trip may need more then 20 bateries just for GPS and flaslights

 

[Closet_Flashaholic]

Describing battery performance is very complex. You must take into consideration the temperature, number of charge/discharge cycles on the battery, how it was charged, what was the discharge current, what was the cutoff voltage during discharge, etc. Most people want a simple answer and with batteries there are none. Edison said "Whenever you are talking about batteries you are lying". To me this means that the behavior is so complex that you cannot really describe it.

Ok, I agree to an extent, with this. So I will put out some relatively simple ground rules:

1) The battery should be able to deliver the rated spec, for at least 100 cycles, otherwise the savings over primary batteries that the manufacturers often quote are a complete lie.

2) Let's just say room temperature (68F/20C) for testing. I would be happy with that

3) Let's say that the charge rate is .5C and the discharge rate is .25C. This should be a reasonable number.

If the manufacturer is going to quote numbers, then they should supply the testing methods, if they are to be believed.

In my case, the powerex batteries don't meet their spec. even if I discharged at .1C. You could make the argument that I charged them at too high of a rate, but at less than .5C (1000 mAH), they didn't even get very warm.

I would be happy with +/- 10% of spec, but the powerex aren't even close. Eneloops seem to be... So I do agree with Edison, that there is a lot of lying going on in the battery industry.

Hence my original post, in the real world has anybody run across "real" 2700 mAH batteries. No post yet has made that claim. Some come close, but close only counts in horse shoes and hand grenades, as the saying goes....

 

[MattK]

I believe that you're making 2 mistakes here. Firstly, you are relying on a $100 device to be accurate to testing standards. Secondly, you're making up your own testing standards when a set already exisits - a set that is universally accepted within the battery industry.

Battery capacities - except for those being wilfully and wildly inflated - are quoted based on IEC testing standards. While too lengthy (and copy protected) to post fully here the capacitance testing procedure is a basically charge at .2C, rest 1hr, discharge at .1C to 1V, rest 1 hr, repeat.
The standard also stipulates environmental factors, how many cycles are to be performed, which results kept, etc. It's far more complex than one might think.

 

[Closet_Flashaholic]

I believe that you're making 2 mistakes here. Firstly, you are relying on a $100 device to be accurate to testing standards. Secondly, you're making up your own testing standards when a set already exisits - a set that is universally accepted within the battery industry.

Battery capacities - except for those being wilfully and wildly inflated - are quoted based on IEC testing standards. While too lengthy (and copy protected) to post fully here the capacitance testing procedure is a basically charge at .2C, rest 1hr, discharge at .1C to 1V, rest 1 hr, repeat.
The standard also stipulates environmental factors, how many cycles are to be performed, which results kept, etc. It's far more complex than one might think.

Possibly I am making "mistakes" but, if my expectations are too high, or my testing equipment / methodology is not accurate enough, why do Eneloop batteries continue to meet my specifications and no other manufacturer can? I have (many) batteries rated from 1600-2300 mAH (from 4 or 5 different manufacturers) that all seem to meet "my" specifications. It's only the 2700 mAH (or higher batteries) that don't seem to meet my expectations...

All testing methodologies aside, and granted mine are self-defined (based on my needs), real world results are what matter to me. Specifications (and the measurement there of) only go so as you've correctly pointed out.

The real bottom line for me is, are there any AA batteries that can sustain 2700 mAH rating at 0.25C for over 100 cycles @ room temperature? In the end, that's all that I care about - how long is this battery going to last in my application.

The original (and current) intent of this post was to see if anyone else has had good experiences with "high" (sic) capacity AA batteries. If anyone responds with glowing recommendations, I would be willing to try those in my application.

I only use specifications as a guide to suitability to any given application and so far, the specs for 2700 mAH batteries suck. Plain and simple. The conclusion that I am starting to come to is that there is no such thing as a 2700 mAH AA battery. The manufacturers are just playing games with their testing in the race to claim the highest numbers.

 

[TakeTheActive]

...2 of my AA cells are finished in the charge test mode.
A ANSMANN battery previously mistakenly by myself believed to be around 3400, has finished with a reading on 000...

...just waiting for 1 more ansmann, and I hybrio to finish cooking now.
Would I be right in thinking the 000 reading indicates a dud cell, that is not of much use comparably to others ?

"000 mA" is the La Crosse OVERHEAT indicator.

• What Charge Current did you use?
• Was the cell HOT when you removed it?
• Charging at less than 0.5C CAN OVERHEAT / cook cells!

 

[TakeTheActive]

...you're making up your own testing standards when a set already exisits - a set that is universally accepted within the battery industry.

Battery capacities - except for those being wilfully and wildly inflated - are quoted based on IEC testing standards. While too lengthy (and copy protected) to post fully here the capacitance testing procedure is a basically charge at .2C, rest 1hr, discharge at .1C to 1V, rest 1 hr, repeat...

Unless you're quoting something other than the IEC Capacity Analysis (C9000s BREAK-IN function), you appear to have transposed your numbers:

• Charge @ 0.1C for 16 hours
• Rest for 1 hour
• Discharge @ 0.2C (to 0.9VDC)
• Rest for 1 hour
• Charge @ 0.1C for 16 hours

 

[TakeTheActive]

It was explained to me sorry, I did overlook this unfortunately, not intentionally, my memory is that bad, owing to brain damage.
To satisfy my curiosity, and to ensure more accuracy from myself I take on board what you have said, I have just put my BC 700 into "charge test" mode on 2 X Uniross Hybrio's, and 2 X Ansmann cells in AA format

Ah, this answers my 'Charge Current' question from my earlier post (700/350mA MAX).

Please redo the TEST function in your BC-900 @ 1000/500mA and report the results.

Also please monitor the cell temperatures during the Charge periods (should be MUCH shorter @ 1000mA compared to your usual 200mA).

Thanks!