# Test/Review of Eneloop AA HR-3UTGB 1900mAh (White)



## HKJ (Apr 13, 2013)

[size=+3]Eneloop AA HR-3UTGB 1900mAh (White)[/size]







Official specifications:

Capacity typical: 2000mAh
Capacity minimum: 1900mAh
Nominal voltage: 1.2V
Fast charge: 2000mA
Life cycles: up to 1800 
Self-Discharge: approx. 70% capacity after 5 years






Maximum temperature raise at different discharge currents: 1A:+1,2°C, 2A:+3,3°C, 3A:+5,8°C, 5A:+11,3°C, 7A:+16,6°C, 10A:+22,1°C, 
































These batteries can handle large discharge currents..

































[size=+3]Conclusion[/size]

These batteries have over the years proves to be very good batteries for just about any application I have used them in.
I really like the low self discharge and the ability to deliver high currents.



[size=+3]Notes and links[/size]

How is the test done and how to read the charts


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## Bumble (Apr 13, 2013)

Many thanks for another excellent review HKJ . eneloop aa are excellent batteries, and with the above data you can see why they are highly recommended.


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## Mr Floppy (Apr 14, 2013)

Nice work! Does this mean you'll be doing other NiMH battery tests and reviews in the future?


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## HKJ (Apr 14, 2013)

Mr Floppy said:


> Nice work! Does this mean you'll be doing other NiMH battery tests and reviews in the future?



I have planned a few and there will probably come other later, but not anything like the LiIon tests.

The actual test takes about 8 days (0.1A test is slow).


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## Lurveleven (Apr 15, 2013)

Your test results corresponds very well with what my MAHA C9000 test my batteries to. I find that the standard AA Eneloops to perform a little on the low side, while the AAAs however have consistently been very close around 800 mAh. I just got some of the latest generation AA XX cells (3UWXB), I have just tested one pack yet, but so far they are really impressive, they gave from 2566 to 2583 mAh. This is up to 37% more than the standard cells. So I'm changing to the XX cells in equipment where more runtime is of importance.


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## Mr Floppy (Apr 15, 2013)

HKJ said:


> I have planned a few and there will probably come other later, but not anything like the LiIon tests.
> 
> The actual test takes about 8 days (0.1A test is slow).



I really appreciate the time. It's also really nice to see the internal resistance figure. I knew it was low but that is on par with some LiIons. How do you calculate this by the way? Open circuit voltage and voltage under load?


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## HKJ (Apr 15, 2013)

Mr Floppy said:


> Open circuit voltage and voltage under load?



For NiMH I uses the voltage at 1A and the voltage at 3.5A.


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## B-52 (Apr 18, 2013)

Are these eneloops Available in the States i did see them on Amazon but that was about it i wouldn't having a Set..


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## candle lamp (Apr 19, 2013)

Excellent test review. HKJ! I've used these batteries for several years. :thumbsup:

Thanks for your hard work for doing different test.


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## Mr Happy (Apr 19, 2013)

I wonder if these batteries were brand new out of the pack when they were tested, or if they had been cycled a few times first? It is often reported that eneloops gain performance after a few cycles and if they were brand new it might explain the slightly low capacity measurements?


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## HKJ (Apr 19, 2013)

Mr Happy said:


> I wonder if these batteries were brand new out of the pack when they were tested, or if they had been cycled a few times first? It is often reported that eneloops gain performance after a few cycles and if they were brand new it might explain the slightly low capacity measurements?



I did give them one break-in on my MH-C9000, before I tested them. The Maha did also report higher capacity than I measured, this might be due to the way they are charged.


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## Bucur (Apr 26, 2014)

Thank you for another excellent review, HKJ. :thumbsup:

I bought 8 of these batteries. My intention was to make a 5-cell battery pack for my R/C car transmitter and using the other 3 in my flashlights. First of all, I “soft conditioned” them all with my MAHA C808M charger. Then, I discharged them @ .3A, individually, down to .9V with my hobby charger. Their capacities were as follows:

#1: 975 mAh (second discharge w/o recharging: 281 mAh, total: 1256 mAh).
#2: 90 mAh (second discharge w/o recharging: 1657 mAh, total: 1747 mAh).
#3: 1750 mAh
#4: 1750 mAh
#5: 1751 mAh (despite initial voltage sag).
#6: 1783 mAh
#7: 1731 mAh
#8: 1769 mAh

I “soft conditioned” them all, a second time. Then, I increased the discharge current to 1A. Their capacities down to .9V were as follows:

#1: 2 mAh (severe voltage sag. Second discharge w/o recharging: 281 mAh)
#2: 50 mAh (severe voltage sag. Second discharge w/o recharging: no avail).
#3: 1479 mAh
#4: 1385 mAh
#5: 1341 mAh (despite initial voltage sag).
#6: 1491 mAh
#7: 1479 mAh
#8: 1493 mAh

It was clear that #1, 2 and 5 were not eligible for my pack but I gave #4 another chance because it did not sag @1A discharge rate. It was just a little lazier than the best ones. I charged it individually @ .5A but it didn't seem to give a clue to the charger for terminating the charge cycle. When I manually terminated the charge cycle, it was @ 1.70V and 3600 mAh were pumped in it! I was surprised that it was just warm, not hot at all! I was further surprised when it supplied 1711 mAh @1A discharge down to .9V. It was not toasted. To the opposite, it was now the best performer of the lot. Since my MAHA C808M charges @ 1A during “soft conditioning”, I concluded that the slower charge rate of .5A did the trick. Am I correct in my assumption? 

Anyway, I made the pack with cells #4, 8, 6, 3 and 7. I gave the pack .5A charge and 1A discharge down to 4.5V (.9 volt/cell). It supplied 1851 mAh! Better than #4 alone!! I repeated the same cycle and the pack was very consistent: 1856 mAh. 

I made another cycle at double the charge rate: 1A charge and 1A discharge to 4.5V. I was expecting a drop in capacity due to higher charge current but the pack supplied exactly 1856 mAh again. If lower charge rate had made the above trick, the capacity of the pack should have been reduced after doubling the charge rate. Shall I conclude that the merits of multiple initial cycling overruled the stress of doubling the charge rate? 

I now have a very consistent pack, with more than enough juice for my R/C transmitter and its extremely low self-discharge rate is a big bonus. It doesn't miss charge terminations either. It peaked @ 7.67 and 7.70V at .5A charge rate (1.534 and 1.54 V/cell, respectively). This climbed to 7.85V (1.57V/cell) @ 1A charge rate. I would like to charge the pack faster. Even if the official specs seem to allow 2A charge rate, would this harm the cells? If not; shall I expect reduced capacity? Or, is it probable that this would lead to another surprise like further increased capacity (again @ 1A discharge rate, of course)? 

I think #1 and #2 are crap. Is this correct? If so, would you like to suggest a cycling method or something for recovering #5? This may be a good excuse for buying a new single AA cell flashlight! 

Thank you for reading all this. I couldn’t consult w/o letting you know my findings. Besides, this may be an interesting story, after all…


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## SilverFox (Apr 26, 2014)

Hello Bucur,

One of the interesting things about LSD cells is that they seem to form a passivation layer across the electrode. This slows down the self discharge rate but also can interfere with initial performance if the cells have been idle for an extended period of time. 

When matching Eneloop cells for a battery pack I will cycle them 4 - 5 times charging at 1000 mA and discharging at 500 mA. I pay attention to the charge cycle to make sure the end of charge has been detected and occasionally will have to manually terminate the charge. I don't pay any attention to the discharge capacity during this process.

At the end of this "waking up" process I will then do a Break In utilizing a 16 hour 0.1C charge, followed by a rest period, then ending with a 0.2C discharge. That gives me an idea of the maximum capacity I can expect from the cell. At this point I am ready to match the cells for the battery. I will charge and discharge at rates similar to how the cell is expected to be used and match the performance based upon those numbers.

You may find that the capacities move around a little until you have 10 or so charge/discharge cycles on them. Still it looks like you have a good matched set for your transmitter. The other cells may come back into line just by running a few more charge/discharge cycles on them. 

Tom


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## Bucur (Apr 27, 2014)

Thanks a lot, Silverfox. I noted down your suggestions for the future. This is an invaluable guideline for me. 

I wonder if I can still improve the performance of the pack before starting to actually use it. With the exception of the initial discharge at 300ma, I have always discharged the individual cells and the pack at 1000ma. Would you suggest a few cycles @ 1000ma charge and 500ma discharge rates even after what I have already done? 

If so, I can then break-in the pack as per your “waking up” process. Would this still be beneficial or is it too late for this? 

In any case, what would you like to suggest about charging @ 2000ma? I have no temp probe but the pack gets warmer @ 1A charge rate than it gets @.5A. I can even say that it gets slightly hot. I am pretty sure it will get hot @ 2A. I know such a subjective temp description doesn’t mean a lot but what is your general opinion about 2A charge rate?


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## SilverFox (Apr 27, 2014)

Hello Bucur,

By this time your cells should be OK to just use.

I have found that charging that 1000 mA works very well for Eneloop cells. With that said I have no issues with charging at higher rates. 1000 mA is convenient for me so I tend to use that more than other rates. In a rush I have even used 15 minute chargers with Eneloop cells without problems.

Tom


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## Bucur (Apr 27, 2014)

Thanks again, Tom. I will stick to 1A charge rate unless I am in a real hurry. 

Given that Eneloops are LSD batteries, I would also appreciate your suggestions on how to treat my new pack. My routine with non-LSD NiMH battery packs was recharging them just before using and discharging them just afterwards, no matter how much capacity I had used. I was keeping them in discharged state for a week or so until recharging them for the next session. During the off season, I was cycling them monthly or so. 

If I use only 15-20% of the capacity of my Eneloop pack during a single session, would it be reasonable to keep it 80-85% full afterwards for a week or so and then, repeating this for several weeks until re-charging is called for? Nevertheless, I would discharge the pack to .9V/cell before recharging.


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## SilverFox (Apr 27, 2014)

Hello Bucur,

Eneloop cells have changed things a lot. The current thinking is to use them until they are discharged and them charge them back up. If it takes a few years to do so then that is just the way it is. I run a charge/discharge cycle every 6 months just out of habit but I am not sure that is needed. Once a year may be fine. The only thing that seems to destroy these cells is leaving them trickle charging for extended periods of time.

If you have extras that you plan on storing for 3 - 5 years it is probably best to go with the factory charge of about 75%.

Tom


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## Etsu (Apr 27, 2014)

SilverFox said:


> Eneloop cells have changed things a lot. The current thinking is to use them until they are discharged and them charge them back up. If it takes a few years to do so then that is just the way it is.



I haven't heard that there is any problem with topping them up before use. I usually charge mine about twice a week for the ones I use in my main flashlights, even though they probably still have well over half a charge. I've never noticed any problem doing this, in fact, I think NiMH have always been "memory effect" free.

Where did you get your information that it is better to deplete their charge entirely before recharging?


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## SilverFox (Apr 27, 2014)

Hello Etsu,

With Eneloops it doesn't seem to matter. Both topping them up or using them until they are empty seem to work fine.

Tom


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## Bucur (Apr 28, 2014)

SilverFox said:


> Eneloop cells have changed things a lot. The current thinking is to use them until they are discharged and them charge them back up. If it takes a few years to do so then that is just the way it is.





SilverFox said:


> With Eneloops it doesn't seem to matter. Both topping them up or using them until they are empty seem to work fine.



The above sound more like revolution than evolution! My old transmitter pack was LiFe. That is, I am shifting from LiFe to NiMH but with Eneloops, this seems to be a step forward rather than a step back. Sure, LiFe stores more energy per volume/weight but it needs delicate periodic maintenance, balance charging, etc.. Besides, it doesn't last half as long despite all this maintenance. 

LiFe makes sense for high current applications like electric motors and when weight/mass reduction is crucial. I also use LiPo and/or LiMN (IMR) in my newer flashlights but IMHO Eneloop is the way to go when it comes to low-drain electronics.


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## kreisl (Nov 30, 2014)

Would it be okay to charge Eneloop AA with 3.0A (=1.5C) instead of the forum-typical 1.0A (=0.5C)?

My charger test unit  supports the max charge rate of 3 amps per slot and i would like to test it without harming the cells


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## HKJ (Nov 30, 2014)

kreisl said:


> Would it be okay to charge Eneloop AA with 3.0A (=1.5C) instead of the forum-typical 1.0A (=0.5C)?
> 
> My charger test unit  supports the max charge rate of 3 amps per slot and i would like to test it without harming the cells



The rated charge current is 1C, i.e. 2A


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## SilverFox (Nov 30, 2014)

Hello Kreisl,

"OK" is a relative term...

As HKJ pointed out the maximum recommended charge rate is 2A. Is it possible to exceed that? Yes, but pay attention to the heat generated in the cell. In addition don't expect to get the same number of cycle life that you would get from following the manufacturers recommendations.

If you look through the archives you will find a thread where I tested Eneloop cells using the Energizer 15 minute charger. That may offer some insight to rapid charging.

Tom


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## kreisl (Nov 30, 2014)

Thanks for your comments! I could probably test the 3amps charging with a 1s3p-AA round battery holder. I don't intend to compromise the cell life only for the sake of research and testing.

Tom i found your numerous posts on CPF regarding the 15min Duracell/Energizer chargers (search post term <energizer> post author <silverfox>  ) but not a dedicated thread started by you, i believe that Dave did a video on the 15min Varta in 2 parts.


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## WalkIntoTheLight (Nov 30, 2014)

kreisl said:


> Thanks for your comments! I could probably test the 3amps charging with a 1s3p-AA round battery holder. I don't intend to compromise the cell life only for the sake of research and testing.



In that configuration, you're really doing a 1A charge (to each cell). That should be perfectly fine.


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## kreisl (Nov 30, 2014)

SilverFox said:


> but pay attention to the heat generated in the cell.



I just did the test, 4×3A on depleted Eneloop AA cells (2nd gen)! I measured the current of slot#3 and it was indeed 3 amps. The fan kicked in after a couple of minutes and all four cells finished charging after 40mins. By the end of the program all cells had slightly crossed the 40°C mark (as measured by the charger itself, not by me my own thermometer!), the hottest cell was in slot#3 with max *43.7°C*. Such temperature feels uncomfortably warm/hot to the touch tbh. Charging terminated perfectly right after the max voltage was reached, -dV. The (+)metal contacts of the charger were mildly warm at this point, not hot: very good! It means that most amount of the cell hotness was definitely produced inside the cell itself (cell internal heat generation = internal battery resistance*high current²) and did not originate from the inside of the charger by thermal conduction through the metal contacts. In fact, heat always "flows" from the hotter to the less hotter spot; thus the hot cell _could _be the cause of the warm metal contacts and not vice versa.

20mins later the cells had cooled down to ~33°C: I recorded the entire 60mins of my PC Link test software as animated GIF (time compressed to 8mins), but since nobody in the DC2 thread is requesting a share, no need to post it 

hmm... thinking of round 1s3p or 1s4p battery holders, in theory it would be possible to charge *12*Eneloop AA* batteries (each at 1 amp) or *16*Eneloop AAA* (each at 0.75A) in the DC2 simultaneously, even though charging NiMH's in parallel is not the best idea unless the cells are nicely identical regarding condition, age, capacity, etc, e.g. from the same manufactured batch. Argh now i feel i must buy such round parallel holders and buy more Eneloops to test this theory yikes!

lovecpf


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## WalkIntoTheLight (Dec 1, 2014)

kreisl said:


> I just did the test, 4×3A on depleted Eneloop AA cells (2nd gen)! I measured the current of slot#3 and it was indeed 3 amps. The fan kicked in after a couple of minutes and all four cells finished charging after 40mins. By the end of the program all cells had slightly crossed the 40°C mark (as measured by the charger itself, not by me my own thermometer!), the hottest cell was in slot#3 with max *43.7°C*.



That doesn't sound too bad. I've certainly had old (non LSD) cells get hotter than that when charging at much lower currents.


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## kreisl (Dec 1, 2014)

I checked the temperature graph, the cell in slot#3 had 39.0°C at 1.47V. That's the voltage threshold where the MH-C9000 stops the original CHARGE phase and continues with the 100mA top-off charge for 2.0hrs (followed by 10mA trickle charge) in order to keep the batteries unheated. The DC2 user can emulate (more or less) the Maha charging behavior by setting TARGET VOLT to 1.47V and TRICKLE charge to 100mA, thus keeping all AA cells below 39°C at 3 amps. When charging a D cell or C cell with 3 amps, the respective max temperatures would be notably lower, no doubt.

In future i won't charge a single AA with 3 amps again. 3A and the internal heat generation can't be healthy for a single AA battery


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