NiMh Battery Shoot Out

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shadowjk

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My guess is that they go back to alkalines and start putting them into the charger they bought for their nimh.
 

jasonck08

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Hi there SilverFox, thank you so much for all of these tests. it has been about 20 days since your last update, and I'm quite curious how the GP ReCyko stack up against the Sanyo Eneloops. Does anyone know?

Also, after looking at the charts, it appears that just about any GP, Sanyo, or Energizer does reasonably well with 5amp's of load. These are the 3 easy to find brands in Taiwan. So I'll end up getting either some cheap GP, Sanyo or Energizers or perhaps some GP ReCyko or Sanyo Eneloops. Thanks!
 

Raymond

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About the chip online test: I think the way they tested the batteries is probably correct for the way the batteries are used. They claim to test the batteries for use with digicams. They test the AA-capacity with a 400mA discharge current, which they say would be typical for a digicam (I trust that's correct, I'm not really familiar with digicams that use AA's). They also test self-discharge after 10 days. I think for the intended use, that makes sense. Digicams go through their batteries fast, and usually their use is "planned": vacations, trips, special occasions etc. So you often charge the batteries in advance, but shortly before the planned use. I think 10 days makes sense.
They also use a professional charger/analyzer, the cadex 7200. If they followed the correct procedures, I trust that their measured results are correct.
So that the eneloops gave a 6.7% discharge in the first 10 days is disappointing, and for me a little unexpected, after all the rave reviews here on CPF.

Also, keep in mind that there's a clear top3 (2 varta's and a sanyo) and that numbers 4-25 are very close together. Sometimes is just the price that responsible for a large difference in overall score (just look at the difference between #6 and #18: 20mAh and 0.3% discharge, which is hardly measurable).

So for the intended purpose of this test, I think it's a good test. The results just don't translate well to flashlight use. Discharge currents are often higher in flashlights (my modest romisen RC-A3 has 3x the discharge current that's used in this test), and they're used differently. Selfdischarge after 10 days is not really relevant. Self-discharge (or should I say capacity?) after 2 months is much more interesting to know, if you need a light when you've blown a fuse at night :)
 

Black Rose

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There is another test on here about the Eneloops that show they lose the most power in the first 30 days and then lose less as time goes by. The 60 and 90 day tests showed lower levels of loss.
 

UnknownVT

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So that the eneloops gave a 6.7% discharge in the first 10 days is disappointing, and for me a little unexpected, after all the rave reviews here on CPF.

That figure does seem very high.

But all NiMH have their fastest discharge initially -
and LSDs (which are basically still NiMH) do so as well -
but LSD discharge slows down significantly so that eneloops claims retention of 85%, or loss of only 15% after one year -
compared to regular NiMH which can lose all of their useful charge in about 3 months or less.

However for more relevant information please read SilverFox's thread -

Eneloop Self Discharge study
 
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SilverFox

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Hello Raymond,

While the Eneloop cells may have a 6.7% self discharge in capacity over 10 days, that only increases to 7.2% over 30 days. I don't think the 2700 mAh cells do quite as good as that.

Tom
 

Mr Happy

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About the chip online test: I think the way they tested the batteries is probably correct for the way the batteries are used. They claim to test the batteries for use with digicams. They test the AA-capacity with a 400mA discharge current, which they say would be typical for a digicam (I trust that's correct, I'm not really familiar with digicams that use AA's). They also test self-discharge after 10 days. I think for the intended use, that makes sense. Digicams go through their batteries fast, and usually their use is "planned": vacations, trips, special occasions etc. So you often charge the batteries in advance, but shortly before the planned use. I think 10 days makes sense.
Unlike a flashlight, digicams do not have a constant current load. There is a small load when switched on and operating the LCD, but intermittent very heavy loads when writing a photograph to memory and recharging the flash. It is these heavy loads that cause voltage sag in alkalines and is the reason alkalines do not do well in digicams. A 400 mA discharge test may approximate the discharge rate in digicams when averaged over time, but it does not represent actual usage.

I often pick up my camera to take a few pictures without forward planning. I therefore expect it to work immediately and would not have time to charge the batteries in advance. Consequently the self discharge rate over many months is more important to me than just 10 days.
 

Raymond

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Hello Raymond,

While the Eneloop cells may have a 6.7% self discharge in capacity over 10 days, that only increases to 7.2% over 30 days. I don't think the 2700 mAh cells do quite as good as that.

I know, I thought I said that :)
It's just that the people that did this test chose 10 days as their criterium (probably because they thought that this was something that related to reality, and of course because they don't have time to do a 3 month discharge test :) ). And there's no getting around the fact that the eneloops lost almost 7% of their charge in that time. Consider their reasoning: a varta 2700mAh battery has a capacity of 2363mAh after 10 days, a sanyo eneloop has 1754mAh after 10 days, but the eneloop costs €0,25 more per battery. I think that recommending that Varta over the Eneloop would make sense for a lot of users.

Unlike a flashlight, digicams do not have a constant current load. There is a small load when switched on and operating the LCD, but intermittent very heavy loads when writing a photograph to memory and recharging the flash. It is these heavy loads that cause voltage sag in alkalines and is the reason alkalines do not do well in digicams. A 400 mA discharge test may approximate the discharge rate in digicams when averaged over time, but it does not represent actual usage.

I often pick up my camera to take a few pictures without forward planning. I therefore expect it to work immediately and would not have time to charge the batteries in advance. Consequently the self discharge rate over many months is more important to me than just 10 days.

I agree about the intermittent heavy loads placed on the battery. I think they should have adressed this in their test. Just like they should have pointed out the differences between LSD and "normal" nimh's, so readers could base their decision on what battery to buy on the way they use their camera. Because like you said, there are also a lot of people who use their camera irregurarly and without forward planning. They would be a lot better off with LSD cells (or with a camara that has it's own li-ion battery!).

The test is not perfect, but I don't think they're completely wrong either. They chose a specific set of criteria to test with, and I still think that those criteria make sense. It's always up to the individual to make their own decisions. But if someone bases his choice on the results of this test, I don't think he would make a wrong one. I think the top3 of that list would make very good digicam batteries. It's just that they have the typical high discharge rate of regular nimh cells.
 

Bones

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The test is not perfect, but I don't think they're completely wrong either. They chose a specific set of criteria to test with, and I still think that those criteria make sense. It's always up to the individual to make their own decisions. But if someone bases his choice on the results of this test, I don't think he would make a wrong one. I think the top3 of that list would make very good digicam batteries. It's just that they have the typical high discharge rate of regular nimh cells.

Admittedly, it is difficult to fault the magazine's actual test results since they were based on a completely subjective criteria, but there can be little doubt that for every week their test period could have been extended, the worse their top picks would have fared.

Further, there can be no doubt that they committed a major blunder by extrapolating the the self-discharge rate of the Eneloop after one year based on its self-discharge rate after 10 days; to wit:

Akkus is to be able to hold still 85 per cent of the charge according to manufacturer after one year. Completely the promise cannot be kept however: With seven per cent self discharge in ten Tagen* is the Sanyo eneloop noticeably below the average one year shelf-life is however clearly too optimistically set.

I have yet to see a real-world test that didn't substantiate Sanyo's claim that the Eneloop will retain 85% of its charge after one year.

Admittedly, there have be fluctuations, but there are also very few dwellings that I am aware of where the summer temperature doesn't rise well above the constant 20°C used by Sanyo, which would adversely effect the test results.

As well, it is highly unlikely that there would be a corresponding decrease in the ambient temperture since the thermostats in most dwellings are set to engage the heating system at about 20°C.

Excerpted from a message received at stefanv.com from a Mr. Taetow, Vice President General Affairs at SANYO Component Europe GmbH:

1. The Eneloop batteries are sold charged, but not necessarily 100% fully charged. In Europe we charge them about 75%. I am not sure to which degree they are charged before being sold in Canada. Thus it is rather vague to estimate the discharge rate by calculating backwards to the production date. Also, the storage conditions (transport, warehouse, shop, etc.) are unknown (see point 3 below).

2. Several long term tests have shown that the self-discharge rate decreases over time. This means that Eneloop batteries discharge relatively fast at the beginning and relatively slower the longer you store them. To get real (long-term) test results, you have to store them and wait. An estimation of long-term discharge rate by extrapolating short term storage results is not correct and leads to rather poor results. This may explain the differences you have seen.

3. Storage temperature is of high importance if you measure self-discharge rate. Higher temperatures substantially increase self-discharging. It is best to store Eneloops as cool as possible to keep the charge in the battery. As a rule-of-thumb, every 10°C increase in storage temperature is equivalent to doubling the storage time. Some R/C pilots in Europe put Eneloops in the freezer, with rather good results.

Had they chosen a broader test criteria, and taken the time to determine the Enleloop's actual self-discharge traits, there is a good possibility their readership would now be aware of just how superior the Eneloop is outside of the magazine's narrowly defined purpose, and accordingly be well on their way to foregoing alkalines.

I am also mindful of the well-documented tendency for the vast majority of high-capacity NiMH cells to develop exceeding high self-discharge rates after comparatively little time in service.

It is in consideration of these two factors that I feel the magazine did their readership a major disservice ...
 

Raymond

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Since there's no big thread where you can post testresults of batteries, I'll post mine here :)

I've done some simple charge/discharge tests on Panasonic AA infinium LSD batteries. The specs say "capacity up to 2100 mAh"

At first, I was disappointed, because even after about charge/discharge cycles, the battery I was testing only showed a capacity of about 1700-1800mAh.
But I retested it again this weekend, and it's up to a capacity of 2050mAh, tested at a discharge rate of 500mA.

Eventually, I will test all 6 of my infiniums (4xAA and 2xAAA), but that will take a lot of time. I give them 5 charge/discharge cycles, which take about 6 hours each. Testing all 6, will take about a week :)

When I have all the results, I'll post them here. And eventually, I'll also do some voltage tests, when I've finally decided which DMM I'm going to get :)
 

FILIPPO

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excuse me but I can't find the graph of elites 1700...
anyone have a direct link?
 

SilverFox

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Hello Flippo,

Here is one from Cheapbatterypacks.

Keep in mind that their test methods are a little different from mine. The charge at high rates, then do the discharge test immediately while the batteries are hot. These results would not be as good if you let the batteries cool off before testing them. However, they appear to be very strong batteries.

Tom
 

FILIPPO

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Hello Flippo,

Here is one from Cheapbatterypacks.

Keep in mind that their test methods are a little different from mine. The charge at high rates, then do the discharge test immediately while the batteries are hot. These results would not be as good if you let the batteries cool off before testing them. However, they appear to be very strong batteries.

Tom

thanks!
will you test these batteries one day? :twothumbs
 

1dash1

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Silverfox:

Hi! I'm new here and not well-versed in tech stuff. Ask me a rule of golf question and I can give you chapter and verse on the ruling, ask me about the differences between a C123A and a 14400(?) battery and I'll likely give you a blind look. :popcorn:

I'm sorry that I didn't stumble onto this discussion group a month ago, before I purchased a bunch of NiMH rechargeables, LED flashlights, and charger. I think I could have avoided some poor purchases. :whistle:

At least one of the purchases seems to have been okay, that being the MH-C9000.

I don't understand how to evaluate my C9000 test results relative to the NIMH Battery Shootout test results. You earlier made reference to ...

... "Charging is done on a Vanson BC-1HU. Green light + 30 minutes."

... "Cycling is done in the "Refresh" mode on the La Crosse BC-900 charger at 500 mA charge rate and 250 mA discharge rate."

I'm sorry, but I don't understand what to make of these statements, relative to how my C9000 operates.

If I wanted to check my batteries against the NIMH Battery Shootout results, would I run a few charge-discharge cycles (500 mA charge rate and 250 mA discharge rate), then do a "Refresh & Analyze"?



Note: This question is related to another discussion on this board, "NIMH Battery Shootout compared with MAHA C9000".
https://www.candlepowerforums.com/threads/196260
 

SilverFox

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Hello 1Dash1,

Welcome to CPF.

There are a few things you can do to compare your results with those in the shoot out.

Start by using the Break-In mode. This mode takes around 48 hours to complete, so be patient. The results you get should come pretty close to the labeled capacity of the cell. Also, your capacities should be similar between similar cells.

For example, right now I am testing some Tinko cells that are labeled as 3400 mAh. These are obviously fakes, but let's see what I came up with for results.

The Break-In mode gave me the following results:

1720 mAh, 2113 mAh, 2110 mAh, and 2119 mAh.

As you can see, they are not 3400 mAh cells by any stretch of the imagination. Also, cell 1 is not consistent with the others.

This is what you don't want to see when you check your cells.

I then ran a few charge and discharge tests and the results were similar.

If you want to compare your results to the graphs listed, you need to charge the cells up, then discharge at 500 mA. You can then compare your capacity to the 500 mA discharge curve in the shoot out. Next you can charge the cells back up and discharge them at 1000 mA. Once again, you can compare your results with the 1 amp discharge rate curve in the graphs.

Good luck.

Tom
 

1dash1

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Silverfox:

Will do. Thanks a lot!

Results shown after break-in mode done for the DigiMate 2700 AA's:
Battery: #1 ___ #2 ___ #3 ___ #4 ___ #5 ___ #6 ___ #7 ___ #8
mAH: ....2283__ 2373__ 2377__ 2490__ 2320__ 2313__ 2170__ 2109
volt: ....1.40 __ 1.40 __ 1.39 __ 1.41 __ 1.44 __ 1.42 __ 1.42 __ 1.42

Not very promising for purported 2700 mAH batteries, eh?

We'll see what happens after a couple of charge-discharge cycles.
 
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1dash1

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Silverfox:

Well, here are the results after break-in and two cycles on the C9000:

DigiMate 2700 AA's:
Battery: .....#1 ___ #2 ___ #3 ___ #4 ___ #5 ___ #6 ___ #7 ___ #8
Cycle 1: ....2245__ 2356__ 2336__ 2446__ 2334__ 2349__ 2193__ 2116 (mAH)
Cycle 2: ....2233__ 2348__ 2331__ 2429__ 2317__ 2344__ 2142__ 2121 (mAH)
Average: ..2239__2352 __2334__2438__2326__2347 __2168__2119 (mAH)

% of 2700: .....83% ___ 87%___ 86% ___ 90%___ 86% ___ 87%___ 80% ___ 78%

Results for individual batteries from one cycle to the next were pretty consistent. Results across the eight batteries tested varied quite a bit. The mean of all the averages was 2290 mAH or 85% of the manufacturer's advertised 2700 mAH.

These results would put the DigiMate 2700 in the range of some of the batteries labeled as 2400 to 2500 mAH capacities, shown on the opening page of this discussion string.

I'm a little disappointed with the initial results, but we'll see how they perform in actual service. I suppose that as an uneducated buyer, I should be happy to get away without having them explode on me. :party:

P.S. I'm looking forward to testing my year-and-a-half old MAHA 2700 AA's for comparison.
 
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