The AA NiMH Performance Test Thread

[Battery Guy]

Greetings Everyone,

I have been doing a lot of performance tests on AA NiMH cells recently and posting the results in various threads. I thought that it might be nice to put these results all in one place and update it as more come in.

I hope that this data set will be a nice complement to the comprehensive and exhaustive testing that Silverfox has performed in his NiMH Shootout.

My purpose here is to provide a bit more detailed test results on the more popular NiMH batteries.

Test Setup

All cells are discharged on a Maccor series 4300 battery tester. Nickel tab strips are spot welded to each cell to minimize contact resistance. Unless otherwise noted, cells are discharged to a 0.8 V cut-off. All cells were purchased new and tested within a few weeks of receipt. With the exception of the Elite 1700s and Shnoopaloops, all cells were tested fresh out of the package. The Elite 1700s and Shoopaloops went through one break-in cycle on a Maha C9000 prior to testing. Cells are charged at a 1C rate with a 10 mV -dV cut-off, then allowed to rest for 1 hour prior to discharging.

Limitations

One cell is hardly what I would call a statistically significant sample. There is certainly going to be variability in cell performance, so please recognize this limitation. Unfortunately, I do not have the time to repeat this work on multiple samples. Also, this testing does not take into account performance degradation that occurs over time due to aging and cycling (except for the Shnoopaloop constant current tests). These results are what you might expect for new cells. Exactly how the cells degrade will depend on the cell design, manufacturing quality and your use/abuse pattern.

In other words, your mileage may vary.

Constant Current Discharge Results

Constant current discharge is very close to what a battery sees in an incan hotwire flashlight. For these types of unregulated lights, you really want to know what the voltage of the cell is under load so that you can match it to the bulb output. I hope that these curves serve to compliment the excellent tests that LuxLuthor performed on incan bulbs, the results of which are posted here.

Each plot will show the performance of the cell under constant current discharge conditions compared to a "control" cell. The control cell that I have chosen is the "Gen 1" white label Eneloop. The plots for the Eneloop are in black, and the plots for the "cell of interest" are in blue. Each plot will show the curves for 1A to 10A discharge in 1A increments. In addition, I am adding a 0.2C constant current discharge curve to some of the plots. The 0.2C discharge was conducted in accordance with the IEC capacity measurement standard. To keep the plots clean looking, I am not going to label each curve. I think that it is easy enough to figure out which curve is which.

Constant Power Discharge Results

Constant power discharge is what your battery experiences in a device that has a voltage regulator. Many LED flashlights use a voltage regulator so that the LED always "sees" the same voltage and current from the battery pack. As the battery pack is drained and the voltage of the pack decreases, the current draw on the pack increases to maintain a constant voltage and current for the LED.

The constant power results are presented in the form of a Ragone plot. If you are not familiar with Ragone plots, read the Intro to Ragone plot thread. Ragone plots are a great way to compare the performance of several batteries under various constant power loads on the same plot.

Most of the cells will be discharged up to 8W. I have taken a few cells above 8W, notably Eneloops, Elite 1700, PowerGenix and Imedion 2400. However, limitations of my test equipment make it difficult to go above 8W, so unless it is specifically requested, expect all future results to go up to 8W.

Here is the Ragone plot for the NiMH cells I have tested so far. I know that technically the PowerGenix cell is not an NiMH type, but it is often used in applications where an NiMH might be used so I thought that I would include it.

Here are the constant current discharge curves.


Elite 1700: One break-in cycle was run on a C9000 prior to testing. Please note that these tests were performed on Elite 1700 cells purchased back in June 2010. Testing of more recent Elite 1700 cells has shown that they perform less well at high currents. For a comparison between the new and old Elite 1700 cells, see the end of this thread.

Energizer 2300 Tested fresh out of the package.

Shnoopaloops: One break-in cycle was run on a C9000 prior to testing. These are Duraloops purchased from Shnoop. They are essentially three year old Eneloops. See here for the thread to read more detail.

"Gen 2" 1500x Eneloop: Tested fresh out of the package. Please note that this graph does NOT have a 1 amp discharge curve. The curves shown are from 2 amp to 10 amp.

Imedion 2400: Tested fresh out of the package.

Sanyo 2700: Tested fresh out of the package.

Sanyo 2500: Tested fresh out of the package.

PowerGenix NiZn: Tested fresh out of the package. Please note that the voltage axis is scaled differently than the other comparisons.

GP Recyko: Tested fresh out of the package

Eneloop XX: Tested fresh out of the package. A special thanks to CPF member *Dusty* who shipped me cells all the way from Northern Ireland for this testing! :thanks:

TruCell: Two of these cells were sent to me by CPF member TurboBB.

Rayovac Platinum: Tested fresh out of the package.

Tenergy 2300 LSD: Tested fresh out of the package.

Elite 2000: These appear to perform as advertised, but don't hold their voltage quite as well as the original Elite 1700s

Edit: New January 5, 2011

I was looking over some of my test data and realized that I could extract some additional information that might be of interest to CPF members. In particular, the total discharge energy (Wh) available as a function of discharge current, the efficiency (percent of total available energy) as a function of discharge current, and the energy loss as heat as a function of discharge current. I have included these plots below for your consideration.

Discharge Energy (Wh) vs Discharge Current (A)

Energy Efficiency (%) vs Discharge Current (A)

Energy Loss as Heat (Wh) vs Discharge Current (A): I think that this is a rather interesting plot. The amount of energy lost in the form of heat will determine how hot a battery will get during discharge. The higher the energy loss, the hotter the battery will get (assuming that all of these cells have similar heat capacities).

Hope you find this useful. If there are other NiMH cells of interest, let me know and I will do my best to test them. However, it is not my intention to do this testing on every available NiMH cell on the market, only the more common ones that are of general interest to the CPF community.

Cheers,
BG

 

[Linger]

Excellent. I agree with your rational for including the nizn.

New cells makes for a good purchase comparison, but 1 year old / 100 cycled cells would be a grand shoot-out for use-down-the-road. I understand the challenges with aging cells equally, but want to throw the idea out there in hopes that in a few months maybe someone's got an idea.

Cell recommendation: Eneloop Tones / Gen2 (1500cycle) eneloops. I do not have them to contribute at present (waiting for a deal at Dell.ca) Does any one have some gen2 eneloops to volunteer?

 

[Notsure Fire]

Very nice looking graphs.

 

[Battery Guy]

New cells makes for a good purchase comparison, but 1 year old / 100 cycled cells would be a grand shoot-out for use-down-the-road. I understand the challenges with aging cells equally, but want to throw the idea out there in hopes that in a few months maybe someone's got an idea.

I agree that it would be very nice to know how the performance changes with use. The problem with cycling is that you can never get agreement on how the cells should be cycled, or if the cycling in the lab represents cycling in the field. It also takes quite a bit of time and ties up the test equipment. I don't think that I have enough time or equipment to commit to a cycling study.

Cell recommendation: Eneloop Tones / Gen2 (1500cycle) eneloops. I do not have them to contribute at present (waiting for a deal at Dell.ca) Does any one have some gen2 eneloops to volunteer?

I have already tested the new "Gen 2" 1500x Eneloop and will post those results soon. Spoiler alert: they perform the same as the Gen 1 Eneloops.

Cheers,
BG

 

[Battery Guy]

Greetings Everyone,

I have added the detailed test results for Elite 1700, Eneloop Gen 1, Eneloop Gen 2, Energizer 2300, Imedion 2400, Sanyo 2500 and Sanyo 2700. The constant current curves for the PowerGenix will be posted on Monday.

Any other batteries of interest?

Hope you guys find this useful.

Cheers,
BG

 

[tandem]

Thanks for putting up the new cell types BG!

I'll break the ice and ask a question rather than pollute this fine thread with a guess that may be backasswards - using the Imedion 2400 constant current chart (compared to the Eneloop Gen 1) - what in a nutshell is the chart telling us about performance at different rates of current flow? What sort of applications would you prefer to use one cell over another?

 

[Mr Happy]

I'll break the ice and ask a question rather than pollute this fine thread with a guess that may be backasswards - using the Imedion 2400 constant current chart (compared to the Eneloop Gen 1) - what in a nutshell is the chart telling us about performance at different rates of current flow? What sort of applications would you prefer to use one cell over another?

The Immedion is showing significantly lower voltages under moderate to heavy loads, which would translate to lower brightness if used to drive an incandescent hotwire. At the same time it would deliver about 15 minutes extra run time.

You might choose the Immedion for light load applications where the run time is more important to you, such as in a digital camera. Of course, this chart does not tell you anything about durability, capacity maintenance, or self-discharge performance in the long term.

 

[kxenl]

Hello Tandem! To me as a user of Pentax KX DSLR it tells me that Eneloop gives me about twice the runtime compered to Imedeon. Something like Eneloop 1250 mAh vs Imedeon 650 mAh when the voltage is too low for decent operation. Thanks for good info BG!

 

[Battery Guy]

Thanks for putting up the new cell types BG!

I'll break the ice and ask a question rather than pollute this fine thread with a guess that may be backasswards - using the Imedion 2400 constant current chart (compared to the Eneloop Gen 1) - what in a nutshell is the chart telling us about performance at different rates of current flow? What sort of applications would you prefer to use one cell over another?

I often use these curves to estimate how bright a hotwire mod will be with a different battery. An example would be the typical Mag 85 mod that uses a WA1185 bulb and 9 NiMH cells. From LuxLuthor's destructive testing, we see that the bulb draws ~3.5 amps. If I wanted to get an estimate of the brightness midway through discharge between an Eneloop and an Imedion, I would look at the voltage of the cells at about 1 Ah for ~3.5 amps. From the curves, I would estimate this voltage to be 1.15 V for the Eneloop and about 1.12 V for the Imedion. So for a 9 cell pack, that means 10.35 V for the Eneloop and 10.08 V for the Imedion. From Lux's testing, that would correspond to ~10% difference in lumen output, which I might be willing to live with to get the extra runtime from the Imedion.

If you repeated this analysis with the Elite 1700 cell, you would find that the 9 cell pack voltage would be ~11.2 V midway through discharge, which corresponds to ~30% increase in brightness over the Eneloops.

Cheers
BG

 

[tandem]

Good info and examples folks, thanks.

 

[Battery Guy]

Results for PowerGenix NiZn have been added.

Please let me know if you have any recommendations for other cells that should be added.

Cheers,
BG

 

[Mr Happy]

The sustained high voltage at heavy load stands out for the NiZn.

It would be interesting to overlay NiZn and Energizer lithium on the same plot, given that NiZn is sometimes thought of as a rechargeable replacement for the lithiums. (But I'm not asking you to waste a bunch of L91s just for that purpose.)

 

[Battery Guy]

It would be interesting to overlay NiZn and Energizer lithium on the same plot, given that NiZn is sometimes thought of as a rechargeable replacement for the lithiums. (But I'm not asking you to waste a bunch of L91s just for that purpose.)

Hi Mr. Happy,

A bunch of L91s would not be necessary since they really cannot sustain constant current loads above 3 amps. The L91s are normally considered to be high power cells, but when compared to most secondary cells, they really don't have the same power capabilities.

I agree that the NiZn-L91 comparison would be interesting and I might do that test and post the results in a separate thread. Perhaps 0.5 A to 3 A discharge at 0.5 A increments? Target has L91s on sale for 7.99 a 4 pack this week and I would be willing to sacrifice $12 to run six tests on the L91 if people would get some value out of it.

Thanks for the suggestion Mr. Happy.

Cheers,
BG

 

[InHisName]

This is my first time at trying the DeJaVu. I hope this turns out well.


Re: The AA NiMH Performance Test Thread
Written by Battery Guy on 02-19-2011 12:19 PM GMT

So the estimation is derived mathematically,
that makes sense. It is surprising how the Elite 1700 stands out so
much. The last three plots (Discharge Energy (Wh), Energy Efficiency
(%), and Energy Loss as Heat (Wh) vs Discharge Current (A)) really show
the effect of internal resistance.

Yes, the Elite 1700 is really quite different from the other NiMH
cells, and it does have spectacular high rate performance. I only wish
that someone would make an LSD cell that had similar performance
characteristics. The big problem with the Elite 1700 is a high
self-discharge, and relatively high self-discharge rate variability from
cell-to-cell. This means that you need to "rebalance" a multi-cell
pack relatively relatively frequently by charging at a low rate. Yes, the Elite 1700 is really quite different from the other NiMH
cells, and it does have spectacular high rate performance. I only wish
that someone would make an LSD cell that had similar performance
characteristics. The big problem with the Elite 1700 is a high
self-discharge, and relatively high self-discharge rate variability from
cell-to-cell. This means that you need to "rebalance" a multi-cell
pack relatively relatively frequently by charging at a low rate.

Re: The AA NiMH Performance Test Thread
Written by Battery Guy on 02-21-2011 08:19 AM GMT

Discharge curves have been added for the Tenergy 2300 LSD AA cell.
I had high hopes for this cell based on a couple posts in other
threads, but its performance really let me down. The IEC discharge
capacity was only 1.98 Ah, and the cell has substantial voltage sag at
higher currents.

From an "out of the package" performance perspective, this cell is
definitely worst in class, at least for the LSD cells I have tested so
far.

Re: The AA NiMH Performance Test Thread
Written by InHisName on Yesterday 04:25 AM GMT

Great new plots! Battery Guy

Two of them really show differences in that I kept seeing Eneloopxx,
TruCell, Energizer2300, and Eneloops all coming in "2nd" to the 1700.

Since I have plenty of cells I'll probably only jump if any one has
bargain offerings somewhere. I wouldn't mind trying 4 or 8 if I

Re: The AA NiMH Performance Test Thread
Written by 080 on Yesterday 06:47 PM GMT

Hello, anyone ever tested or have experience with the AAturnigy low self discharge (not tenergy)

battery from HobbyKing. They are 2200mah and consistently charge to
2350mah. Any data knowledge appreciated especially for use in torches.

Re: The AA NiMH Performance Test Thread
Written by Mr Happy on Yesterday 07:59 PM GMT

Hello, anyone ever tested or have experience with the AA turnigy low self discharge (not tenergy)

battery from HobbyKing. They are 2200mah and consistently charge to
2350mah. Any data knowledge appreciated especially for use in torches.

There are two kinds of battery in the world: there are Eneloops
and there is everything else. The Turnigy batteries are not Eneloops... There are two kinds of battery in the world: there are Eneloops
and there is everything else. The Turnigy batteries are not Eneloops...

discovered approx $1 per cell.

 

[Battery Guy]

I have updated the first post in this thread and added the lost content from the server crash.

And a special thanks to InHisName for adding the lost threads!

Cheers,
BG

 

[JA(me)S]

*deleted*

 

[JA(me)S]

Below are all cached posts from November 2 2010 through to the end of February 2011.
This represents original posts sequentially from #14-95.
No information was lost in this thread when the lights went out at CPF.

A special thank you to InHisName for finding posts 91-95.:thumbsup:



Re: The AA NiMH Performance Test Thread Written by Battery Guy on 12-03-2010 02:37 PM GMT

Greetings Everyone Data for GP Recyko AA NiMH cells have been added to the first post. Enjoy! Cheers, BG



Re: The AA NiMH Performance Test Thread Written by brainy1000 on 12-03-2010 05:15 PM GMT

Many thanks for your time and efforts, lots of valuable info here, specially for including the ReCykos! :thumbsup:



Re: The AA NiMH Performance Test Thread Written by LetThereBeLite on 12-05-2010 02:49 AM GMT

Greetings Everyone, One cell is hardly what I would call a statistically significant sample. There is certainly going to be variability in cell performance, so please recognize this limitation. Unfortunately, I do not have the time to repeat this work on multiple samples. Also, this testing does not take into account performance degradation that occurs over time due to aging and cycling (except for the Shnoopaloop constant current tests). These results are what you might expect for new cells. Exactly how the cells degrade will depend on the cell design, manufacturing quality and your use/abuse pattern. Shnoopaloops: These are Duraloops purchased from Shnoop. They are essentially three year old Eneloops. See here for the thread to read more detail.

Cheers, BG

Hi BG, thanks for your time and effort in conducting the tests and then posting the results. :thumbsup: Much appreciate it! I have a few clarification questions, if I may. I'm curious to know what, if anything, you did to your control GEN-1 eneloop before conducting the discharge test on your Maccor 4300 tester. I.e., did the eneloop undergo one, or several, break-in forming charge(s) before being discharged on the Maccor 4300 test? Did you cycle charge it a few/several times before conducting the discharge test, or did you just charge it to full once straight out of the package and immediately conducted the Maccor Discharge test? Secondly, with regards to the Schnoopaloop used in the above graph, what, if anything, did you do to it prior to conducting the Maccor Discharge test? Was it formed charged--once or several times--before the Discharge test? Was it cycle charged a few times before conducting the Discharge test? Looking at your graph above, it seems to indicate there may be some voltage depression of the Schnoopaloop given its age. So I'm really curious whether you tested it straight out of the package--without any forming break-in charges or cycle charges to remove or reduce the voltage depression--or whether you 'broke' it in first before discharge testing it. I'd appreciate the clarification. Thanks! I'm hoping that 3, or more, cycles of 'break-in' on the Maha C9000 would/will help reduce the voltage depression of the Schnoopaloop to a negligible amount. But if you can confirm that you repeatedly 'broke' in the Schnoopaloop before conducting the Discharge Test, then I have less hope to be optimistic about reducing/eliminating the voltage depression indicated by your graph. I purchased 12 AAs and 4 of them have just been 'discharged' on my C9000. They are currently running through their obligatory 'break-in' cycle. I will report my test results in the other Schnoopaloop thread--so as not to clutter your thread here.



Re: The AA NiMH Performance Test Thread Written by Battery Guy on 12-05-2010 06:18 AM GMT

I'm curious to know what, if anything, you did to your control GEN-1 eneloop before conducting the discharge test on your Maccor 4300 tester. I.e., did the eneloop undergo one, or several, break-in forming charge(s) before being discharged on the Maccor 4300 test? Did you cycle charge it a few/several times before conducting the discharge test, or did you just charge it to full once straight out of the package and immediately conducted the Maccor Discharge test? Secondly, with regards to the Schnoopaloop used in the above graph, what, if anything, did you do to it prior to conducting the Maccor Discharge test? Was it formed charged--once or several times--before the Discharge test? Was it cycle charged a few times before conducting the Discharge test? Looking at your graph above, it seems to indicate there may be some voltage depression of the Schnoopaloop given its age. So I'm really curious whether you tested it straight out of the package--without any forming break-in charges or cycle charges to remove or reduce the voltage depression--or whether you 'broke' it in first before discharge testing it.

I usually test everything directly out of the package, with only an initial discharge at 0.5 A or 1 A to bring the cell down to 0% SOC before applying the first charge. But, looking back at my notes, it appears that I did indeed run the Shnoopaloops through a break-in cycle on my C9000 prior to running the tests. Cheers, BG



Re: The AA NiMH Performance Test Thread Written by Mikl1984 on 12-05-2010 06:31 AM GMT

I usually test everything directly out of the package, with only an initial discharge at 0.5 A or 1 A to bring the cell down to 0% SOC before applying the first charge.

It's not right according IEC 61951-2 You should discharge at 0.2C before charge at 0.1C withing 16 hours Maha's Break-In is almost follows all IEC recomendations (except discharge till 0.9V contrary 1.0V IEC)



Re: The AA NiMH Performance Test Thread Written by LetThereBeLite on 12-05-2010 06:45 AM GMT

I usually test everything directly out of the package, with only an initial discharge at 0.5 A or 1 A to bring the cell down to 0% SOC before applying the first charge. But, looking back at my notes, it appears that I did indeed run the Shnoopaloops through a break-in cycle on my C9000 prior to running the tests. Cheers, BG

Thanks for the response BG. You state "a" break-in cycle, so I'm interpreting that to mean one break-in cycle. I've read elsewhere that cells which suffer from voltage depression can be "cured" (but really I think helped is a better word) with several cycles of full discharge then recharge. Do you think you could try this and then repeat your test, when you have time? What I'm asking is that, when you have time, you use the 'cycle' feature on the Maha C9000 and cycle the Shnoopaloops for 5 times, then try the Discharge Test on your Maccor 4300 again. I'm really curious to see if the voltage depression seen on the Shnoopaloops will improve--or can be improved--or stay the same as your original test. Thanks much! http://www.stefanv.com/electronics/u...tml#depression

Fortunately, voltage depression can be cured. Fully discharging and then recharging a battery two or three times usually brings the voltage back to where it should be. A battery manager is ideal for this.

Re: The AA NiMH Performance Test Thread Written by Battery Guy on 12-05-2010 06:56 AM GMT

It's not right according IEC 61951-2 You should discharge at 0.2C before charge at 0.1C withing 16 hours Maha's Break-In is almost follows all IEC recomendations (except discharge till 0.9V contrary 1.0V IEC)

Correct me if I am wrong, but the IEC 61951-2 standard is for measuring and reporting the total cell capacity. If so, I don't think that it applies for these tests. Cheers, BG



Re: The AA NiMH Performance Test Thread Written by Battery Guy on 12-05-2010 07:02 AM GMT

Thanks for the response BG. You state "a" break-in cycle, so I'm interpreting that to mean one break-in cycle. I've read elsewhere that cells which suffer from voltage depression can be "cured" (but really I think helped is a better word) with several cycles of full discharge then recharge. Do you think you could try this and then repeat your test, when you have time? What I'm asking is that, when you have time, you use the 'cycle' feature on the Maha C9000 and cycle the Shnoopaloops for 5 times, then try the Discharge Test on your Maccor 4300 again. I'm really curious to see if the voltage depression seen on the Shnoopaloops will improve--or can be improved--or stay the same as your original test. Thanks much! http://www.stefanv.com/electronics/u...tml#depression

Correct, I only did one break-in cycle on the Shnoopaloops. However, I do not believe that the Shnoopaloops are suffering from "voltage depression", as it is commonly understood. The Shnoopaloops are suffering from having a higher internal resistance, so if you discharge them very slow, they have the same voltage as new eneloops. With voltage depression, the cell discharges at a lower voltage even at relatively low discharge rates. This is why I do not think that running additional break-in cycles will have an impact, but it is worth a try if you are curious. Cheers, BG



Re: The AA NiMH Performance Test Thread Written by LetThereBeLite on 12-05-2010 07:10 AM GMT

Correct, I only did one break-in cycle on the Shnoopaloops. However, I do not believe that the Shnoopaloops are suffering from "voltage depression", as it is commonly understood. The Shnoopaloops are suffering from having a higher internal resistance, so if you discharge them very slow, they have the same voltage as new eneloops. With voltage depression, the cell discharges at a lower voltage even at relatively low discharge rates. This is why I do not think that running additional break-in cycles will have an impact, but it is worth a try if you are curious. Cheers, BG

Thanks for the explanation. That makes sense. As for me being curious, yes I am. I purchased 12 of those Shnoopaloops and I would like to hope that there is something that can be done to improve their performance. As I don't have your testing equipment, I can't test it myself and thus must ask you for help in quenching my thirst for this info. But I realize you're busy and your test equipment is meant for "real work", so as I emphasized above, please do these cycles only at your leisure and as time and equipment permits. Thanks.



Re: The AA NiMH Performance Test Thread Written by Mikl1984 on 12-05-2010 08:48 AM GMT

Correct me if I am wrong, but the IEC 61951-2 standard is for measuring and reporting the total cell capacity. If so, I don't think that it applies for these tests.

You are wrong I have russian translation of this standard http://www.gostu.ru/data/18985.pdf But numbers are international Standard discribe total cell capacity but in 0.2C till 1V; 1C, 5C, 10C till 0.9V. Also discribe cycling, different temperature testing(for example 0 Celsius at 2 and 3C till 0.8V), overcharge conditions etc. Your test are really interesting but will be even more useful if it comply IEC mA



Re: The AA NiMH Performance Test Thread Written by Mr Happy on 12-05-2010 11:00 AM GMT

You are wrong I have russian translation of this standard http://www.gostu.ru/data/18985.pdf But numbers are international Standard discribe total cell capacity but in 0.2C till 1V; 1C, 5C, 10C till 0.9V. Also discribe cycling, different temperature testing(for example 0 Celsius at 2 and 3C till 0.8V), overcharge conditions etc. Your test are really interesting but will be even more useful if it comply IEC mA

I think Battery Guy is doing fine It is only important to follow the IEC standard test protocol if you are reporting results according to that standard. It is not "wrong" to use other procedures if you describe those procedures and are consistent in applying them. In this case BG simply said he discharged the cell before charging it. That is a good procedure and is exactly what I do too.



Re: The AA NiMH Performance Test Thread Written by Mikl1984 on 12-05-2010 11:35 AM GMT

You are wrong too According 5.3 Measuring Battery Energy [FONT=Times New Roman,Times New Roman][FONT=Times New Roman,Times New Roman] The battery shall be charged, according to Section 5.1 of this test methodology. After charging, the battery shall be stored in an ambient temperature of 20 °C ± 5 °C for not less than 1 hour and not more than 4 hours. The battery shall then be discharged in an ambient temperature of 20 °C ± 5 °C at a rate of 0.2C, where C is the rated Ampere-hour capacity of the battery. The test shall continue until the battery pack reaches its end of discharge voltage, according to Table 1. During this period, voltage shall be logged, integrated at the end of discharge, and multiplied by the discharge rate to obtain battery energy. The test may be repeated a maximum of 5 times, as in IEC 61951, with the best result being chosen as the final measured energy value. [/FONT][/FONT]http://www.energystar.gov/ia/partner...est_Method.pdf I only recommend: - to follow charge and conditioning IEC standards to receive reliable results - to add 0.2C and 1C discharge test to test pattern



Re: The AA NiMH Performance Test Thread Written by Battery Guy on 12-05-2010 02:23 PM GMT

You are wrong too According 5.3 Measuring Battery Energy [FONT=Times New Roman,Times New Roman][FONT=Times New Roman,Times New Roman] The battery shall be charged, according to Section 5.1 of this test methodology. After charging, the battery shall be stored in an ambient temperature of 20 °C ± 5 °C for not less than 1 hour and not more than 4 hours. The battery shall then be discharged in an ambient temperature of 20 °C ± 5 °C at a rate of 0.2C, where C is the rated Ampere-hour capacity of the battery. The test shall continue until the battery pack reaches its end of discharge voltage, according to Table 1. During this period, voltage shall be logged, integrated at the end of discharge, and multiplied by the discharge rate to obtain battery energy. The test may be repeated a maximum of 5 times, as in IEC 61951, with the best result being chosen as the final measured energy value. [/FONT][/FONT]http://www.energystar.gov/ia/partner...est_Method.pdf I only recommend: - to follow charge and conditioning IEC standards to receive reliable results - to add 0.2C and 1C discharge test to test pattern

Hi Mikl1984 I am familiar with the IEC standards, and again it is not the purpose of my tests to report the cell capacity. The purpose of the IEC standards is to provide cell manufacturers with a standardized way of reporting total cell capacity. The purpose of my tests is to see how the cells perform at different discharge currents. I like your recommendations. I can begin adding an IEC 0.2C discharge curve to the tests and will do so from this point forward. However, I am not really sure how much value that will be for other CPF members because many people already have the ability to make those measurements with the Maha C9000 and other chargers. For the 1 A through 10 A discharge curves, I simply do not have the time to perform the 0.1C charge for 16 hours. This would effectively add 160 hours of instrument time to each test, and I simply cannot dedicate that kind of time. I would like to add one additional comment regarding standardized test protocols. Having participated in my fair share of developing standardized tests, I can tell you that they seldom represent the best way to perform a measurement. Inevitably, the standardized tests end up being a compromise between the participants in the standards committee because there are always competing interests. Again, thank you Mikl1984 for bringing these issues to light. Cheers, BG



Re: The AA NiMH Performance Test Thread Written by Mikl1984 on 12-05-2010 10:06 PM GMT

Hi BG Thanks for understanding my bad English I just want to add, that proposed tests according IEC will help standard users to check manufacture's data, which usually too good to be real. Of course every Maha's user are able to plot discharging curve manually. http://www.candlepowerforums.com/vb/...-via-Maha-data But on your professional equipment it will be more correct



Re: The AA NiMH Performance Test Thread Written by LetThereBeLite on 12-07-2010 07:25 AM GMT

BG, may I ask what you're currently testing for CPF, as opposed to testing for 'real work'. Alternatively, if you're currently not testing anything for CPF, what battery is planned for testing? Thanks!



Re: The AA NiMH Performance Test Thread Written by Battery Guy on 12-07-2010 06:26 PM GMT

BG, may I ask what you're currently testing for CPF, as opposed to testing for 'real work'. Alternatively, if you're currently not testing anything for CPF, what battery is planned for testing?

Unfortunately, "real work" is taking priority for the foreseeable future. Next on the list is the new Eneloop XX cells. I have them on order but probably won't receive them for a week or two since they are being shipped from the EU. Cheers, BG

 

[JA(me)S]

Re: The AA NiMH Performance Test Thread Written by LetThereBeLite on 12-07-2010 06:34 PM GMT

Unfortunately, "real work" is taking priority for the foreseeable future. Next on the list is the new Eneloop XX cells. I have them on order but probably won't receive them for a week or two since they are being shipped from the EU. Cheers, BG

Alrighty. I look forward seeing the test results.



Re: The AA NiMH Performance Test Thread Written by Mikl1984 on 12-07-2010 10:23 PM GMT

Next on the list is the new Eneloop XX cells.

Any plans for AAA testing?



Re: The AA NiMH Performance Test Thread Written by MichaelW on 12-08-2010 01:24 PM GMT

Hi Mr. Happy, A bunch of L91s would not be necessary since they really cannot sustain constant current loads above 3 amps. The L91s are normally considered to be high power cells, but when compared to most secondary cells, they really don't have the same power capabilities. I agree that the NiZn-L91 comparison would be interesting and I might do that test and post the results in a separate thread. Perhaps 0.5 A to 3 A discharge at 0.5 A increments? Target has L91s on sale for 7.99 a 4 pack this week and I would be willing to sacrifice $12 to run six tests on the L91 if people would get some value out of it. Thanks for the suggestion Mr. Happy. Cheers, BG

If [when] 4sevens puts the Cree xm-l into the QuarkMini AAx2, what cells would be optimal? A 14500 in a QMini AAx1 is probably going to be unusable on Maximum output mode [Vf @ 3 amps is 3.35 volts] and splitting a CR-V3 is going to be too expensive (so that you match the output of a QMini 123) The Vf of the xm-l at 2.1 amps is 3.2 volts so, NiZn or primary lithium AAs (be it L91 or Duracell Ultra Lithium [is that available in the US?] ) for the QMini AAx2? Thanks.



Re: The AA NiMH Performance Test Thread Written by Battery Guy on 12-09-2010 07:19 PM GMT

The Vf of the xm-l at 2.1 amps is 3.2 volts so, NiZn or primary lithium AAs (be it L91 or Duracell Ultra Lithium [is that available in the US?] ) for the QMini AAx2?

I know nothing of the QMini AA flashlights, so I don't know if they are direct drive or regulated. Let's simply assume that the average per cell discharge will be between 2 and 2.5 W (I am using your current and voltage numbers to get at that range). If you look at the http://www.candlepowerforums.com/vb/showthread.php?278063-AA-Ragone-PlotAA Ragone plot, you will see that at a 2 W discharge, the Energizer L91 will last about 1.3 hours and the Duracell Ultra Lithium (not available in the US) will last a bit longer at 1.7 hours. The PowerGenix will last about 1.1 hours, but it of course is rechargeable. If you now look at 2.5 W discharge, the PowerGenix is at 1 hour, the Energizer is at about 1.1 hours and the Duracell is at about 1.3 hours. So unless you need to use this flashlight at temperature extremes (e.g. your car in the summer and/or winter), this seems like it would be a great application for the PowerGenix cells. The performance is a bit lower, but of course they are rechargeable and you can often find them on sale with a charger for less than the cost of the Energizer Ultimate Lithium cells. Hope that helps. Cheers, BG



Re: The AA NiMH Performance Test Thread Written by Battery Guy on 12-09-2010 07:23 PM GMT

Any plans for AAA testing?

Nothing planned. Sorry! The AA's have been keeping me busy, and I would really like to do more with lithium-ions.



Re: The AA NiMH Performance Test Thread Written by MichaelW on 12-09-2010 08:27 PM GMT

How about a graphical explanation of the QMini family? http://i243.photobucket.com/albums/f.../2AA-HiEne.gif http://i243.photobucket.com/albums/f.../2AA-HiL91.gif http://i243.photobucket.com/albums/f...2AA-HiAlka.gif http://i243.photobucket.com/albums/f...3-HiCR123A.gif http://i243.photobucket.com/albums/f...r123-HiRCR.gif http://i243.photobucket.com/albums/f...niAA-HiL91.gif http://i243.photobucket.com/albums/f...niAA-HiEne.gif http://i243.photobucket.com/albums/f...iAA-HiAlka.gif http://i243.photobucket.com/albums/f...AA-Hi14500.gif With the circuit it is using, more voltage is good. Too much becomes wasteful. A RCR or 14500 in the QMini123 / AA is good for showing off, but will get 2nd degree burn hot with the xm-l. 1st degree burn hot with 2xNiZn in a QMini AAx2 package is okay :thumbsup: Friends don't let friends use alkalines indeed.



Re: The AA NiMH Performance Test Thread Written by Battery Guy on 12-14-2010 09:03 PM GMT

How about a graphical explanation of the QMini family? http://i243.photobucket.com/albums/f.../2AA-HiEne.gif http://i243.photobucket.com/albums/f.../2AA-HiL91.gif http://i243.photobucket.com/albums/f...2AA-HiAlka.gif http://i243.photobucket.com/albums/f...3-HiCR123A.gif http://i243.photobucket.com/albums/f...r123-HiRCR.gif http://i243.photobucket.com/albums/f...niAA-HiL91.gif http://i243.photobucket.com/albums/f...niAA-HiEne.gif http://i243.photobucket.com/albums/f...iAA-HiAlka.gif http://i243.photobucket.com/albums/f...AA-Hi14500.gif With the circuit it is using, more voltage is good. Too much becomes wasteful. A RCR or 14500 in the QMini123 / AA is good for showing off, but will get 2nd degree burn hot with the xm-l. 1st degree burn hot with 2xNiZn in a QMini AAx2 package is okay :thumbsup: Friends don't let friends use alkalines indeed.

In those plots, what is the y-axis relative to? In other words, what is the baseline 100% value setup?



Re: The AA NiMH Performance Test Thread Written by MichaelW on 12-14-2010 10:15 PM GMT

See: http://www.candlepowerforums.com/vb/...lues-to-Lumens and http://www.sliderule.ca/FL1.htm



Re: The AA NiMH Performance Test Thread Written by Battery Guy on 01-03-2011 02:24 PM GMT

Greetings Everyone I know that it has been a long wait, but I have finally added the Eneloop XX data to the first post in this thread. Note that I have only finished the constant current discharge curves. I will be posting the data for the Ragone plot in a few days. My initial impression is very favorable. I had expected these to perform on par with the Imedion 2400, Sanyo 2500 or Sanyo 2700. In fact, they perform nearly as good as the original Eneloops even at very high discharge currents. :thumbsup: Cheers, BG



Re: The AA NiMH Performance Test Thread Written by LetThereBeLite on 01-03-2011 02:38 PM GMT

Greetings Everyone I know that it has been a long wait, but I have finally added the Eneloop XX data to the first post in this thread. Note that I have only finished the constant current discharge curves. I will be posting the data for the Ragone plot in a few days. My initial impression is very favorable. I had expected these to perform on par with the Imedion 2400, Sanyo 2500 or Sanyo 2700. In fact, they perform nearly as good as the original Eneloops even at very high discharge currents. :thumbsup: Cheers, BG

BG, you should have had more faith in eneloop technology. I knew the XX wouldn't let us down. I'll definitely buy a pack when it eventually makes it to stateside. Thanks for doing the testing and getting us the empirical data. :thumbsup:



Re: The AA NiMH Performance Test Thread Written by BVH on 01-03-2011 06:42 PM GMT

Great to see they aretesting out well! Thank you BG for the data.



Re: The AA NiMH Performance Test Thread Written by Battery Guy on 01-03-2011 08:06 PM GMT

BG, you should have had more faith in eneloop technology. I knew the XX wouldn't let us down.

Sorry, but I am not a "have faith" kind of guy. I am a "show me the data" kind of guy...and Sanyo continues to deliver from this perspective with regards to the Eneloops. What surprises me about the new Eneloop XX cells is how much better they perform at high rate compared to the "standard" Sanyo 2500 and Sanyo 2700 cells. In fact, the Eneloop XX cells appear to have higher capacity and better voltage retention than either the Sanyo 2500 or 2700 cells, at least under my testing conditions. Quite frankly, from an initial performance standpoint, it looks like the substantial capacity increase in the Eneloop XX compared to the standard Eneloop is more than worth the very small decrease in voltage retention. Indeed, only the highest power applications (>5 amp) would even notice the difference. Seems like a pretty darn good trade-off to me. The other cell that continues to surprise me is the Elite 1700. That particular NiMH cell performs much better than ANY other NiMH cell with respect to voltage retention. And you only sacrifice 300 mAh compared to the Eneloop for that extra power capability. So right now I would have to say that my favorite AA NiMH cells are the new Eneloop XX and the Elite 1700, as they seem to represent the best of both classes of cells. Unfortunately, the only way to buy the Eneloop XX cells in North America is to mail order them from Europe. Even before shipping the new Eneloop XX cells are 2X the cost of standard Eneloops. Hopefully these will become more readily available and cheaper in the near future. Cheers, BG



Re: The AA NiMH Performance Test Thread Written by Burgess on 01-03-2011 08:09 PM GMT

to Battery_Guy -- Thank You for your time and effort and dedication. :goodjob: Really appreciate seeing yer' data on the new Sanyo XXeloops ! Gonna' hafta' buy a few packs, when they come to U.S.A. :thumbsup: _



Re: The AA NiMH Performance Test Thread Written by fishinfool on 01-04-2011 01:20 AM GMT

Thanks for all of your hard work Battery Guy! I can't wait until these XXeloops start showing up stateside. Hopefully sometime this year......hopefully.



Re: The AA NiMH Performance Test Thread Written by Battery Guy on 01-05-2011 06:01 PM GMT

Greetings Everyone The results for the Eneloop XX have now been added to the Ragone plot in the first post. Also, at the end of the first post you will notice that I added two new plots. These plots are simply another way of looking at data that were collected from the 1A-10A constant current tests. One plot shows the effect of discharge current on total available energy. The other plot shows the effect of discharge current on the efficiency of the cell. I have replaced the Eneloops in my Mag85 with XXeloops. That gives me a real, honest runtime of ~40 minutes, compared to ~32 minutes with standard Eneloops. It sure ain't worth the 2X in cost that I paid, but it is nice to see that the improvement is consistent with expectations. Next cell on the list: AccuEvolution! Cheers, BG



Re: The AA NiMH Performance Test Thread Written by LetThereBeLite on 01-05-2011 06:37 PM GMT

Sorry, but I am not a "have faith" kind of guy. I am a "show me the data" kind of guy...and Sanyo continues to deliver from this perspective with regards to the Eneloops. BG

I can't argue with that logic. I certainly appreciate your empirical data. Nevertheless, I didn't have much suspicion that Sanyo would let us down with their XX loops. I'm happy to see your empirical data confirming it.



Re: The AA NiMH Performance Test Thread Written by Mikl1984 on 01-05-2011 11:03 PM GMT

Also, at the end of the first post you will notice that I added two new plots. These plots are simply another way of looking at data that were collected from the 1A-10A constant current tests. One plot shows the effect of discharge current on total available energy. The other plot shows the effect of discharge current on the efficiency of the cell.

Those graphs are really interesting! Thanks for your work Have you any plan to test LSD (may be on 1A only) after 1(3, 6, 12) month ? Selfdischarge decrease not only mAh, but V also. Therefore energy tests become even more interesting Didn't find promising 0.2C curves



Re: The AA NiMH Performance Test Thread Written by Battery Guy on 01-06-2011 05:51 AM GMT

Those graphs are really interesting! Thanks for your work Have you any plan to test LSD (may be on 1A only) after 1(3, 6, 12) month ? Selfdischarge decrease not only mAh, but V also. Therefore energy tests become even more interesting

I have thought about doing some self-discharge measurements, but right now those plans are still being formulated.

Didn't find promising 0.2C curves

They are coming! I made the IEC charge/discharge measurement on the Sanyo XX and I am in the process of doing it for the other cells. Cheers, BG



Re: The AA NiMH Performance Test Thread Written by Battery Guy on 01-07-2011 12:23 PM GMT

Didn't find promising 0.2C curves

Take a look now. 0.2C discharge curves (performed in accordance with the IEC standard) have been added for the standard Eneloop, Imedion 2400, Energizer 2300, Sanyo 2500, Sanyo 2700 and XXeloop cells. I hope to get the ones for the Elite 1700 and GP Recyko cells in a week or so. You might be interested to know that the IEC capacity of the XXeloop was 2.5001 Ah. That is pretty darn accurate manufacturing if you ask me. I wonder if the precision of their manufacturing is equally as impressive. Hope you find this useful. Cheers, BG



Re: The AA NiMH Performance Test Thread Written by purduephotog on 01-07-2011 01:20 PM GMT

Dare I ask about the Tenergy brands? If I shipped a cell or two? (I need to buy some in the coming months to replace a few that have been totally drained in the baby bouncer....)



Re: The AA NiMH Performance Test Thread Written by Battery Guy on 01-07-2011 02:48 PM GMT

Dare I ask about the Tenergy brands? If I shipped a cell or two? (I need to buy some in the coming months to replace a few that have been totally drained in the baby bouncer....)

You may indeed dare. These are non-LSD, correct?



Re: The AA NiMH Performance Test Thread Written by LetThereBeLite on 01-07-2011 04:22 PM GMT

Take a look now. 0.2C discharge curves (performed in accordance with the IEC standard) have been added for the standard Eneloop, Imedion 2400, Energizer 2300, Sanyo 2500, Sanyo 2700 and XXeloop cells. I hope to get the ones for the Elite 1700 and GP Recyko cells in a week or so. You might be interested to know that the IEC capacity of the XXeloop was 2.5001 Ah. That is pretty darn accurate manufacturing if you ask me. I wonder if the precision of their manufacturing is equally as impressive. Hope you find this useful. Cheers, BG

Thanks for the new data BG! Nice work! Would you consider getting this data for the Schnooloops as well? Thanks!



Re: The AA NiMH Performance Test Thread Written by EntropyQ3 on 01-07-2011 04:53 PM GMT

Awesomeperformance from the new Eneloop XX! Better than I would have guessed, and shows both that Sanyo is on top of their game, and more generally, that true improvement is still to be had in this field. I hope this technology is put to use in AAA size batteries since both capacity and performance under load are more critical for AAA, and not only for flashlight use.



Re: The AA NiMH Performance Test Thread Written by Mikl1984 on 01-07-2011 10:00 PM GMT

Take a look now. 0.2C discharge curves (performed in accordance with the IEC standard) have been added for the standard Eneloop, Imedion 2400, Energizer 2300, Sanyo 2500, Sanyo 2700 and XXeloop cells. You might be interested to know that the IEC capacity of the XXeloop was 2.5001 Ah.

Thanks BG I hope it will be interesting not for me only One remark. According IEC capacity during 0.2C discharge should measure till 1V, not 0.8V as in your tests What's show XXeloop on this limit? And question about accuracy of your device. Are you checked V measurement with good DMM?



Re: The AA NiMH Performance Test Thread Written by LetThereBeLite on 01-07-2011 10:13 PM GMT

Thanks BG I hope it will be interesting not for me only One remark. According IEC capacity during 0.2C discharge should measure till 1V, not 0.8V as in your tests What's show XXeloop on this limit? And question about accuracy of your device. Are you checked V measurement with good DMM?

Hmm. that's interesting. Does the Maha C9000 discharge to .9v or 1v when in its break-in mode? Likewise for Refresh & Analyze, is it discharging to .9v or 1v? I always thought the Maha C9000 was discharging to .9v.



Re: The AA NiMH Performance Test Thread Written by Mikl1984 on 01-07-2011 10:52 PM GMT

Maha discharge till 0.9V during break-in (R&A and Discharge too) And it's only difference in comparison IEC recommendation for 16-hours 0.1C charge and 0.2C discharge after 1 hour



Re: The AA NiMH Performance Test Thread Written by shadowjk on 01-08-2011 02:50 AM GMT

Also I think Maha uses pulsed charging and discharging, which is also different from IEC recommendation?



Re: The AA NiMH Performance Test Thread Written by Mikl1984 on 01-08-2011 03:41 AM GMT

Yes, it's true But due to this you are able to control V during process for example



Re: The AA NiMH Performance Test Thread Written by Battery Guy on 01-08-2011 07:03 AM GMT

One remark. According IEC capacity during 0.2C discharge should measure till 1V, not 0.8V as in your tests What's show XXeloop on this limit?

You can read them off the graph, but if you want more accurate results, here you go: 2.4801 Ah at 1.0001 V 2.4935 Ah at 0.9006 V 2.5001 Ah at 0.8000 V

And question about accuracy of your device. Are you checked V measurement with good DMM?

I use a calibrated Maccor series 4300 battery test system. Most of these tests are run on 0-10V channels with a 0-10A current range. The accuracy of the system is +/-0.02% of full system resolution, which means +/-0.02% of 10 V or 10 A, which is +/-0.2 mV and +/-0.2 mA. Actually, the IEC tests were run with a 0-5 A range, which means that the current accuracy of the IEC tests is +/-0.1 mA. As I mentioned, the system is calibrated. I use the Maccor calibration system, and I double check occasionally with a calibrated Fluke 187 or 189 (I can't remember which one right now). Cheers, BG



Re: The AA NiMH Performance Test Thread Written by Battery Guy on 01-08-2011 08:01 AM GMT

Thanks for the new data BG! Nice work! Would you consider getting this data for the Schnooloops as well? Thanks!

Sure. Not a problem. Cheers, BG

 

[JA(me)S]

Re: The AA NiMH Performance Test Thread Written by Mikl1984 on 01-08-2011 09:51 AM GMT

Thanks for figures and explanations about accuracy What's difference between Maccor and Maha data? Question is due to my measurements http://www.candlepowerforums.com/vb/...d.php?t=303342



Re: The AA NiMH Performance Test Thread Written by 45/70 on 01-08-2011 11:55 AM GMT

Hi BG. Not getting super technical about it, I find it interesting how the Mahas come very close to the IEC 0.2 discharge info you obtained. My results with my Maha C9000's as I remember anyway, were pretty much spot on with your results for the original eneloops, Sanyo Industrial 2500's. and the Sanyo 2700's. If the Maha's are off, on the discharge results, all I can say, is that they appear to be good enough for my personal use anyway. I'm surprised that they are that close, really. Dave



Re: The AA NiMH Performance Test Thread Written by Battery Guy on 01-08-2011 01:38 PM GMT

Thanks for figures and explanations about accuracy What's difference between Maccor and Maha data? Question is due to my measurements http://www.candlepowerforums.com/vb/...d.php?t=303342

Is there a difference? Technically, there should not be any difference, other than the relative accuracy of the Maha and Maccor, and variability between cells.

Hi BG. Not getting super technical about it, I find it interesting how the Mahas come very close to the IEC 0.2 discharge info you obtained. My results with my Maha C9000's as I remember anyway, were pretty much spot on with your results for the original eneloops, Sanyo Industrial 2500's. and the Sanyo 2700's. If the Maha's are off, on the discharge results, all I can say, is that they appear to be good enough for my personal use anyway. I'm surprised that they are that close, really. Dave

I completely agree Dave. I think that the Maha and Maccor results agree very well. I hope that I was not giving the impression that I thought the Maha is deficient with respect to its accuracy. Indeed, for the price, I am very, very impressed with the Maha C9000. Cheers, BG



Re: The AA NiMH Performance Test Thread Written by LetThereBeLite on 01-08-2011 02:57 PM GMT

Well, the Maha discharges to .9v and the IEC specs call for discharges to 1.0v. (I wasn't aware of this difference before. I thought the IEC called for discharging to .9v and that's why Maha discharges to .9v) BG discharges to .8v on his testing--which is perfectly fine, but I think it would be useful to note the 1.0v number as well for quick comparison to official IEC testing protocol results. If I had configurable testing equipment, I would also configure it to discharge down to .8v for personal use, but for comparison with official published numbers from manufacturers, I think discharging to 1.0v--or at least reporting the specific number when the cell reaches 1.0v on its way to .8v--would be useful. Thanks again for your work BG.

Hi BG. Not getting super technical about it, I find it interesting how the Mahas come very close to the IEC 0.2 discharge info you obtained. My results with my Maha C9000's as I remember anyway, were pretty much spot on with your results for the original eneloops, Sanyo Industrial 2500's. and the Sanyo 2700's. If the Maha's are off, on the discharge results, all I can say, is that they appear to be good enough for my personal use anyway. I'm surprised that they are that close, really. Dave

Is there a difference? Technically, there should not be any difference, other than the relative accuracy of the Maha and Maccor, and variability between cells. I completely agree Dave. I think that the Maha and Maccor results agree very well. I hope that I was not giving the impression that I thought the Maha is deficient with respect to its accuracy. Indeed, for the price, I am very, very impressed with the Maha C9000. Cheers, BG

Re: The AA NiMH Performance Test Thread Written by 45/70 on 01-08-2011 03:35 PM GMT

I hope that I was not giving the impression that I thought the Maha is deficient with respect to its accuracy. Indeed, for the price, I am very, very impressed with the Maha C9000.

No problem there, BG. I was just expressing my satisfaction with the C9000's as well.

......Well, the Maha discharges to .9v and the IEC specs call for discharges to 1.0v. (I wasn't aware of this difference before. I thought the IEC called for discharging to .9v and that's why Maha discharges to .9v)......

Hi Let. I'm pretty sure the Maha discharges to 0.9 Volt because it utilizes PWM during discharge, as opposed to constant current. The use of 0.9 Volt with PWM, likely closely approximates a CC discharge to 1.0 Volt. Dave



Re: The AA NiMH Performance Test Thread Written by LetThereBeLite on 01-08-2011 03:38 PM GMT

Hi Let. I'm pretty sure the Maha discharges to 0.9 Volt because it utilizes PWM during discharge, as opposed to constant current. The use of 0.9 Volt with PWM, likely closely approximates a CC discharge to 1.0 Volt. Dave

Good to know Dave. That's a good point.



Re: The AA NiMH Performance Test Thread Written by Mikl1984 on 01-08-2011 11:54 PM GMT

Well, the Maha discharges to .9v and the IEC specs call for discharges to 1.0v.

Not really IEC discribes 0.2C discharge till 1V ONLY For example 1C till 0.9V, more than 1C till 0.8V



Re: The AA NiMH Performance Test Thread Written by Mikl1984 on 01-08-2011 11:56 PM GMT

I'm pretty sure the Maha discharges to 0.9 Volt because it utilizes PWM during discharge, as opposed to constant current.

It seems to me you are wrong



Re: The AA NiMH Performance Test Thread Written by Battery Guy on 01-09-2011 08:13 AM GMT

Not really IEC discribes 0.2C discharge till 1V ONLY For example 1C till 0.9V, more than 1C till 0.8V

Hi Mikl You can discharge a cell to 0.9, 0.8 or even 0.0 V and still be in compliance with the IEC spec, as long as you record the capacity at 1.0 V. Also, at a 0.2C rate, there is very, very little capacity difference between 1.0 V, 0.9 V and 0.8 V. Certainly, for the general hobbyist, this difference is insignificant. The reason that I discharge these cells to 0.8 V is because at the higher drain rates, there can be a significant difference between 1.0, 0.9 and 0.8 V. I am happy to add the IEC discharge curve to these tests, but I think that a detailed discussion of the merits of the IEC, and whether or not the Maha complies with this spec, are too far off topic and deserve their own thread. I would prefer that this thread focus on the performance differences between the cells tested. Cheers, BG



Re: The AA NiMH Performance Test Thread Written by VidPro on 01-10-2011 01:53 AM GMT

:thanks: i dont care what method you test with, as long as we have an idea of the method (is in the post), and that method is used in similarity for the items compared on the same graph. course it helps if the method chosen also realates in some way to reality. Reality is rarely found in the bottom of a pitri dish Prolly the worst thing you could do when compiling the data on ONE graph is to change any methodology mid-stream, then add that to the same graph. soo, keep up the great stuff. , in whatever method you desire to report it in. Unless your going to post at the top that you "Are attempting to test using the manufactures recommended pitri dish". the ragnone plot still rots my brain :mecry:, so i might BEG that when you put in the other graphs below it, showing the tests that the Rate is shown somewhere? or is that another New fangled thing that is there i just aint seeing. (no i cant count to 10, i just want to look at the pretty pictures) it really helped when you put in the 3rd graph type too.



Re: The AA NiMH Performance Test Thread Written by 45/70 on 01-10-2011 09:37 AM GMT

Originally Posted by 45/70 http://www.candlepowerforums.com/vb/showthread.php?p=3648200#post3648200 I'm pretty sure the Maha discharges to 0.9 Volt because it utilizes PWM during discharge, as opposed to constant current.

It seems to me you are wrong

Wrong? Why? The Maha C-9000 utilizes a 1000mA base current when discharging cells. For lower discharge rates (<1000mA), PWM is utilized. The discharge is then terminated at 0.9 Volt. Dave



Re: The AA NiMH Performance Test Thread Written by Mikl1984 on 01-10-2011 09:55 AM GMT

For lower discharge rates (<1000mA), PWM is utilized.

Wrong again PWM is used even in 1000mA mode And coef is 0.91. Maha use non-PWM charge (2A)/discharge(1A) in Service Mode ONLY BG, sorry for off



Re: The AA NiMH Performance Test Thread Written by Battery Guy on 01-11-2011 05:29 PM GMT

the ragnone plot still rots my brain :mecry:, so i might BEG that when you put in the other graphs below it, showing the tests that the Rate is shown somewhere? or is that another New fangled thing that is there i just aint seeing.

Hey VidPro I was attempting to keep the constant current curves "clean", which is why I did not label the curves with specific discharge currents. Every attempt that I have made to do so has made them very, very messy. But I am certainly happy and willing to improve them in any way that will make them more useful. What would you suggest? Cheers, BG



Re: The AA NiMH Performance Test Thread Written by VidPro on 01-11-2011 11:10 PM GMT

Hey VidPro I was attempting to keep the constant current curves "clean", which is why I did not label the curves with specific discharge currents. Every attempt that I have made to do so has made them very, very messy. But I am certainly happy and willing to improve them in any way that will make them more useful. What would you suggest? Cheers, BG

i suggest that i learn to count i agree it would make them more messy, best i can think of is putting cute pointers and baloon statments on the ones that fail miserably, like this <--- see right there at 60Amps it completly fails . just never seen such Integer based chart, by default it IS clean, but it doesnt have .5A in it.



Re: The AA NiMH Performance Test Thread Written by purduephotog on 01-14-2011 09:10 AM GMT

You may indeed dare. These are non-LSD, correct?

No, they are the LSD cells. I have only bought the LSD ones after having such bad experiences with other brands.



Re: The AA NiMH Performance Test Thread Written by LoveLearn on 01-20-2011 09:36 PM GMT

I'd like some help interpreting these excellent cell performance charts. Some loads are generally continuous, even if they vary slightly through time. Regulated and unregulated flashlights are typical of that temporal loading pattern. Some cyclical-pattern loads occur as extended On-&-Off or High-&-Low loading-period series. Examples include portable audio playback and recording devices that present cyclical-pattern loads to their battery/batteries. For instance a motor-driven hard disk or motor-driven CD reader may cycle on and off as the device reads sections of an audio file into volatile memory to sustain a continuous audio playback stream. Those device batteries see a low continuous load which drives the electronics package. On top of that it sees much higher-current brief intermittent loads driving the motor. Both are needed to sustain continuous playback. How should we interpret intermittent cyclical loads as analogs comparable to the continuous curves presented in these very informative charts? Battery-powered devices which present cyclical-pattern loads to batteries are not uncommon. Thoughts? And why do you hold that opinion? Thanks for your consideration, John



Re: The AA NiMH Performance Test Thread Written by Battery Guy on 01-22-2011 06:28 AM GMT

How should we interpret intermittent cyclical loads as analogs comparable to the continuous curves presented in these very informative charts? Battery-powered devices which present cyclical-pattern loads to batteries are not uncommon. Thoughts? And why do you hold that opinion? Thanks for your consideration, John

I was wondering when someone would bring this up. I can tell you that there is a lot of debate about this issue in the battery testing world, and among battery manufacturers. Essentially the battery performance under any load is related to it's total capacity, the instantaneous internal resistance, and the change in internal resistance under an applied load. The change in internal resistance is a result of the inability of ions to diffuse quickly enough in the cell to keep up the discharge current. The result is that ion concentration gradients build up, resulting in a phenomenon known as concentration overpotential, which is a fancy way of saying that the internal resistance increases. You can see the effect of the concentration overpotential if you stop discharging a cell and measure the voltage as it recovers. As soon as you cut the load on the cell, the voltage jumps up. This initial jump in voltage is a result of the ohmic resistance in the cell. If you monitor the cell over time, you will see that the voltage slowly continues to increase. This slower voltage recovery is a result of the concentration gradients relaxing as the ions diffuse throughout the cell. So, getting back to your question. A continuous discharge test, whether it be constant current, resistance or power, is the most strenuous of tests because no time is given for the concentration gradients to relax within the cell. Therefore, differences between cells will usually be more pronounced with continuous discharge tests compared to intermittent discharge tests. There are some exceptions, and it is possible to make a cell that does better on intermittent discharge but worse on continuous discharge (this is essentially what Panasonic did for the Oxyride cell, which does better than alkalines in pulse power applications like digital cameras, but is not as good for moderate to low power applications); however, it is rarely the case with consumer batteries. Hope this helps, Cheers, BG



Re: The AA NiMH Performance Test Thread Written by popoyaya on 01-25-2011 01:49 AM GMT

Hi, fascinating thread and very educational though trying to interpret the graphs is somewhat mindboggling. I would just love to know how bright this torch will be using an AAA NiMH? http://www.dealextreme.com/p/waterpr...ht-1-aaa-47661 And would I be right in assuming that Eneloops in particular can output more sustained power, and therefore more light in a power LED torch? Is there an LSD battery that would be brighter?



Re: The AA NiMH Performance Test Thread Written by VidPro on 01-25-2011 04:43 AM GMT

Hi, fascinating thread and very educational though trying to interpret the graphs is somewhat mindboggling. I would just love to know how bright this torch will be using an AAA NiMH? http://www.dealextreme.com/p/waterpr...ht-1-aaa-47661 And would I be right in assuming that Eneloops in particular can output more sustained power, and therefore more light in a power LED torch? Is there an LSD battery that would be brighter?

eneloop/duraloop would be best "all around" but there can be other factors. many of the lights like this will vary thier regulation with the voltage. In the first few minutes of a fresh alakine , it could be brighter (barely), then that is done. a lithium cell would hold voltage higher and be a bit brighter and should be in spec for energyser lithium cell item. a li-ion (3.6V) cell item would really crank it up, and possibly overdrive it, from the specs users provided, the extra voltage of a li-ion cell would be ok for short runs. it would not give you runtime , but would probably Direct drive the led into more brightness, as long as you didnt burn out the driver, which would take a lot of time to test if that was occuring. the eneloop would be great for longevity durability cycles, and long term storage with it still usable, BUT many other ni-mhy cells could give you tiny bits more capacity for as long as they hold it , for AAA that isnt long even the eneloops AAA are not "durable" cell items. i would say for AAA sizes, knowing the batteries capacity on that day, and its ability to hold voltage under a load today, would be what your asking. so anything good, then you knowing/testing which ones are still working great at the time. so whatever you want, there is some Give and Take in a lot of the different variaties and styles, and give and take with output vrses light longevity parked time, and runtimes.



Re: The AA NiMH Performance Test Thread Written by Battery Guy on 02-08-2011 11:45 AM GMT

New constant current discharge test results added today for the TruCell AA NiMH. The data for the Ragone plot is being collected now and I will post the results by end of week. Special thanks to CPF member TurboBB for sending me two of these cells for testing. Any other recommendations? Cheers, BG



Re: The AA NiMH Performance Test Thread Written by turboBB on 02-08-2011 12:45 PM GMT

Hey BG thx for the data! So looking at your charts, looks like these cells perform quite decently and provided the self-discharge holds up, is probably one of the best values for LSD cells (about $1.25 per cell exc. shipping if ordered direct from mfg site). When the deal was on at Sears, a 20 pack was only $15.99 so worked out to .80 each cell exc. shipping. Cheers, Tim



Re: The AA NiMH Performance Test Thread Written by Battery Guy on 02-08-2011 01:20 PM GMT

Hey BG thx for the data! So looking at your charts, looks like these cells perform quite decently and provided the self-discharge holds up, is probably one of the best values for LSD cells (about $1.25 per cell exc. shipping if ordered direct from mfg site). When the deal was on at Sears, a 20 pack was only $15.99 so worked out to .80 each cell exc. shipping. Cheers, Tim

For the price, they certainly seem to be good performers for low to moderate current applications. I did notice that the wrapper peeled away and exposed the metal can at the seam at some point during the constant current discharge tests. It appears that the cell got sufficiently hot during the high current discharges to cause the wrapper to shrink and pull away from the can. I would want to keep an eye on that if you use these cells in high current devices. Thanks again TurboBB for supplying the cells for testing. Cheers, BG



Re: The AA NiMH Performance Test Thread Written by MorePower on 02-08-2011 03:17 PM GMT

New constant current discharge test results added today for the TruCell AA NiMH. The data for the Ragone plot is being collected now and I will post the results by end of week. Special thanks to CPF member TurboBB for sending me two of these cells for testing. Any other recommendations? Cheers, BG

Rayovac Platinum? PM if you'd like samples.



Re: The AA NiMH Performance Test Thread Written by Battery Guy on 02-10-2011 03:05 PM GMT

Rayovac Platinum? PM if you'd like samples.

Do you mean these? If so, I already have some on order.



Re: The AA NiMH Performance Test Thread Written by MorePower on 02-11-2011 09:19 AM GMT

Do you mean these? If so, I already have some on order.

Those are the ones.



Re: The AA NiMH Performance Test Thread Written by Battery Guy on 02-11-2011 05:37 PM GMT

Those are the ones.

You got it MorePower. I should be able to post the results by the middle of next week. Also, I have heard some good reports on Tenergy LSD AA NiMH cells so I hope to try those soon. Cheers, BG



Re: The AA NiMH Performance Test Thread Written by Battery Guy on Yesterday 11:45 AM GMT

Greetings Everyone, I have added discharge plots for the Rayovac Platinum cells. In addition, I added a new plot: Energy loss as a function of discharge current. The energy is lost in the form of heat, so the higher the energy loss, the hotter the cell will get during discharge. I find this plot interesting because it seems like the data is clustered into three groups, with the highest energy loss associated with the Sanyo 2500, Sanyo 2700 and the Imedion 2400 cells. The lowest energy loss is found in the Elite 1700, of course. The new Tenergy 2300 LSD cells were just put on test today, so expect results early next week. Cheers, BG



Re: The AA NiMH Performance Test Thread Written by Russel on Yesterday 12:54 PM GMT

Battey Guy, how do you determine the energy loss in the form of heat as a function of discharge current? Is the heat measured directly or calculated from the discharge test results. Nice graphs by the way.



Re: The AA NiMH Performance Test Thread Written by Battery Guy on Unknown

Battey Guy, how do you determine the energy loss in the form of heat as a function of discharge current? Is the heat measured directly or calculated from the discharge test results. Nice graphs by the way.

It's quite simple actually. I know the total energy available because I do a low rate discharge. The difference between the total energy and the discharge energy (area under the voltage v capacity discharge curves) is the energy loss. Doing the calculation in this way is actually only an estimate, because it assumes that all of the capacity has been utilized. This assumption gets worse as the discharge rate increases, so at the highest discharge rates, the energy loss that I plot is a slight over estimate. However, I think that it is a good enough estimate for our purposes. Cheers, BG



Re: The AA NiMH Performance Test Thread Written by Russel on Unknown

So the estimation is derived mathematically, that makes sense. It is surprising how the Elite 1700 stands out so much. The last three plots (Discharge Energy (Wh), Energy Efficiency (%), and Energy Loss as Heat (Wh) vs Discharge Current (A)) really show the effect of internal resistance. Thanks for the plots and the explanation!



Re: The AA NiMH Performance Test Thread
Written by Battery Guy on 02-19-2011 12:19 PM GMT

Originally Posted by Russel
So the estimation is derived mathematically,
that makes sense. It is surprising how the Elite 1700 stands out so
much. The last three plots (Discharge Energy (Wh), Energy Efficiency
(%), and Energy Loss as Heat (Wh) vs Discharge Current (A)) really show
the effect of internal resistance.



Yes, the Elite 1700 is really quite different from the other NiMH
cells, and it does have spectacular high rate performance. I only wish
that someone would make an LSD cell that had similar performance
characteristics. The big problem with the Elite 1700 is a high
self-discharge, and relatively high self-discharge rate variability from
cell-to-cell. This means that you need to "rebalance" a multi-cell
pack relatively relatively frequently by charging at a low rate. Yes, the Elite 1700 is really quite different from the other NiMH
cells, and it does have spectacular high rate performance. I only wish
that someone would make an LSD cell that had similar performance
characteristics. The big problem with the Elite 1700 is a high
self-discharge, and relatively high self-discharge rate variability from
cell-to-cell. This means that you need to "rebalance" a multi-cell
pack relatively relatively frequently by charging at a low rate.

Re: The AA NiMH Performance Test Thread
Written by Battery Guy on 02-21-2011 08:19 AM GMT

Discharge curves have been added for the Tenergy 2300 LSD AA cell.
I had high hopes for this cell based on a couple posts in other
threads, but its performance really let me down. The IEC discharge
capacity was only 1.98 Ah, and the cell has substantial voltage sag at
higher currents.

From an "out of the package" performance perspective, this cell is
definitely worst in class, at least for the LSD cells I have tested so
far.

Re: The AA NiMH Performance Test Thread
Written by InHisName on Yesterday 04:25 AM GMT

Great new plots! Battery Guy

Two of them really show differences in that I kept seeing Eneloopxx,
TruCell, Energizer2300, and Eneloops all coming in "2nd" to the 1700.

Since I have plenty of cells I'll probably only jump if any one has
bargain offerings somewhere. I wouldn't mind trying 4 or 8 if I

Re: The AA NiMH Performance Test Thread
Written by 080 on Yesterday 06:47 PM GMT

Hello, anyone ever tested or have experience with the AAturnigy low self discharge (not tenergy)

battery from HobbyKing. They are 2200mah and consistently charge to
2350mah. Any data knowledge appreciated especially for use in torches.

Re: The AA NiMH Performance Test Thread
Written by Mr Happy on Yesterday 07:59 PM GMT

Originally Posted by 080
Hello, anyone ever tested or have experience with the AA turnigy low self discharge (not tenergy)

battery from HobbyKing. They are 2200mah and consistently charge to
2350mah. Any data knowledge appreciated especially for use in torches.



There are two kinds of battery in the world: there are Eneloops
and there is everything else. The Turnigy batteries are not Eneloops...

discovered approx $1 per cell.


Above are all cached posts from November 2 2010 through to the end of February 2011.
This represents original posts sequentially from #14-95.
No information was lost in this thread when the lights went out at CPF.

A special thank you to InHisName for finding posts 91-95.:thumbsup:

 

[Battery Guy]

Thanks Jam(me)s! That is really great!