TESTED – AA LSD Batteries Parts 1,2,3,4 - Introduction ( Eneloop Hybrio infinium etc )

[CaptainD]

Low Self Discharge AA Batteries Tested

Reviewed by Chris Dowling 20th August 2009

This is my first attempt at writing a review which I hope will be informative, and most importantly, will actually be of some practical use to you, the reader. I have had somewhat of a love/hate relationship with rechargeable batteries as I have found it very frustrating going to use a set which turned out to be flat. Even worse, if a set had fully discharged, even after investing in some expensive battery chargers they would then fail to charge, and be effectively useless. I then discovered that battery technology had moved on and low self discharge batteries had become available, which seemed to be the answer to my problems. Up until recently I had no real way of objectively testing rechargeable batteries, but after a failure of one of my Ansmann chargers I did a lot of research to look for a replacement. I bought the very impressive Maha (Powerex) MH-C9000 charger which allows control of charging and discharge rates; most importantly it is able to give the capacity of each battery. It was this purchase that gave me the inspiration for writing this review.

Introduction

Low Self Discharge batteries (LSD) are a development from standard nickel metal hydride (NiMH) batteries. They are ideal for digital photographers and offer some real advantages. The most significant ones in my view are:

1) They will keep their charge when stored for a long time. Typically, the battery capacity will remain around 90% after six months and 80% after 12 months. Remember, standard NiMH will continuously discharge after charging when not in use.

2) LSD batteries have a flatter discharge curve under load which gives longer effective use when compared to a standard NiMH battery (assuming like for like capacity).

3) LSD batteries are supplied from new charged, so you can use them straight away; no delays while charging them.

However, it is not all good news. LSD batteries do have disadvantages when compared to normal NiMH batteries:

1) The maximum capacity of an AA sized LSD is lower. Currently, approx 2000mAh (mAh = milli-Ampere hours) is the largest capacity available. Standard NiMH batteries are available with capacities greater than 3000mAH.

2) Standard NiMH batteries are generally cheaper, but there are some fantastic deals to be had with LSD batteries.

[CaptainD]

Brands of Low Self Discharge AA batteries

I have tried to compile a comprehensive list of brands that you can buy at the time of writing but no doubt there are others available, so please let me know if you spot other brands. Even better, buy a set and lend them to me for testing so that we can see just how good they are!!

(Note – AA capacity data is manufacturer’s claimed figures.)

Extreme Ready to Use

www.qualitydiscounts-online.co.uk

http://s232053959.e-shop.info/shop/article_ext2100i/Extreme-Instant-2100-mAh-Ni-MH-AA-Rechargeable-Batteries.html?shop_param=cid%3D12%26aid%3Dext2100i%26

GP ReCyko

http://www.gprecyko.com/en/index.html



Maha/Powerex Imedion

http://www.mahaenergy.com/store/viewItem.asp?idProduct=426

Panasonic Infinium

http://www.panasonic-batteries.com/site/Europe/English/products/products_batteries_range.asp?iid=27

Rayovac Hybrid



AA capacity – 2100 mAh / 6 months – 80% / 12 months – No data
Price guide for 4 - $34.90 From amazon.com (Unable to find a UK source yet)
Manufacturer’s link - http://www.rayovac.com/recharge/hybrid_products.shtml



Sanyo Eneloop

http://www.eneloop.info/home_en.html



Uniross Hybrio

http://www.uniross.com/consumer_html/see_product.php?ref=U0118675

Vapextech Instant

http://www.vapextech.com.hk/instant.html

[CaptainD]

Testing

I had 6 different brands of AA LSD batteries that I had bought available to test:

Extreme “Ready To Use”
GP ReCyko
Panasonic Infinium
Sanyo Eneloop
Uniross Hybrio
Vapextech Instant.

I decided to subject each brand of four AA LSD batteries to two different tests using the “Refresh & Test” mode offered by the Maha MH-C9000 charger, to determine the capacity of each battery. In this mode the charge and discharge rates are set by the user then the battery is fully charged and rested for one hour before fully discharging the battery. Then the battery is rested again before fully charging the battery again. At the end of the test the charger displays the capacity of the battery.

I chose to test each set of AA batteries twice as I wanted to see if there would be any difference in battery capacity if the batteries were charged and discharged at both low and high rates. Another benefit of testing each set twice was that I hoped that it would validate and highlight any suspicious test results. These tests took a long time to complete as testing just one set at the low rate, for example, took in excess of 10 hours.

Test 1 Low rate






Test 2 High Rate






Test results

Let me first explain the test data

Battery Capacity & Range – Columns 1,2,3,4 are just the capacity of each battery in mAh. For example, if a battery has a capacity of 2000mAh it would be able to supply a load of 500mA for 4 hours or 1000mA for 2 hours. Range (mA) is the difference in capacity between the highest and lowest of the set of batteries under test. Ideally, range should be 0 but there will always be a difference between batteries; the lower the number the better. Range % is the range figure as a percentage of the lowest capacity battery tested; again, the lower the percentage the better.

Capacity of manufacturer’s specifications – Just to see if the capacity of the batteries under test actually matched the manufacturer’s claimed figure. The best result would be 100%.

Best individual battery – The individual battery of the set under test with the highest capacity. To be honest, this in my view is just a nice to know figure and is not really relevant, as a set of 4 batteries will be limited by the worst battery in the set.

Worst individual battery – The individual battery of the set under test with the lowest capacity. This is the result that I was most interested in as the weakest battery of a set will be the one that limits the useful life of a set of batteries.

It is noticeable that higher battery capacity values were recorded in Test 2 which I think is probably due to the Maha charger. There is no obvious reason why a battery would return a better capacity when charged and discharged at a higher rate. To be honest, I would have expected the exact opposite.

When it comes to interpreting the results to decide the good from the bad of the six types of battery brands tested, I was surprised to find that the photo forums’ favorite Sanyo Eneloops did not shine as it is the battery that always gets mentioned and also has the advantage of being the brand that established itself first. Nothing really wrong with them, but other brands performed better.

It was disappointing that the Vapextech Instant returned such a large capacity range over the set tested. The same goes for the GP ReCykos, which produced some good but varied capacity figures. I have to be honest: I bought the Extreme ready to use batteries as I was curious and doubtful that such a generic brand would perform well. Whilst they certainly did not live up to the manufacturer’s capacity claim of 2200 mAh, they were well balanced as a set with good capacity figures.

Next up are the Panasonic Infiniums. I was impressed with how, overall, they were very equally balanced as a set, if not in absolute capacity terms. Especially in Test 1 were there was a range just 11 mA between all 4 batteries tested, excellent.

By a process of elimination, this just leaves the Unross Hybrios which gets my vote as the best on test. Very good capacity figures across the board and combined with equally impressive range figures. As an added bonus, the Uniross Hybrio batteries are far from expensive to buy.


Conclusions / Final thoughts

[CaptainD]

http://www.steves-digicams.com/nimh_batteries.htmlhttp://www.imaging-resource.com/ACCS/BATTS/BATTS.HTM

Battery reviews - Includes Eneloop + Uniross Hybrio (Includes Voltage & Temp graphs)
Excellent article giving out of the box and full recharge performance

http://www.users.on.net/~mhains/Reviews.html

http://en.wikipedia.org/wiki/Low_self-discharge_NiMH_battery

4/3 photo forum threads

http://fourthirdsphoto.com/vbb/showthread.php?t=16736&highlight=eneloop

http://fourthirdsphoto.com/vbb/showthread.php?t=19099&highlight=eneloop

DP review forum thread - http://forums.dpreview.com/forums/re...ssage=25736975

Maha (Powerex) MH-C9000 Charger - http://www.mahaenergy.com/store/view...?idProduct=423

[CaptainD]

[smartwombat]

[j.baker]

[theMusicMan]

[ZZR Puig]

CaptainD. However, one of the crucial aspects of LSD batteries is knowing if the claimed discharge rates are right and how reliable are they in the long run. Obviously, to test that would involve a lot more time and would be much more difficult.

Nevertheless, to have a rough estimate of which battery brands are better in that regard, a couple of tests could be made that wouldn't require to wait a full year.

If you still have the same batteries, the first test would just involve repeating the high rate charge test with them. To see if they have lost maximum capacity during this year of use.

The second one will involve the self discharge rate. Considering that this rate is approximately exponential for all batteries, there is no need to wait for a very long time to get some statistically significant results. I think that just fully charging a couple of batteries of each brand and waiting for 2-3 months (while being able to use the rest normally meanwhile) would give a good estimation of their self discharge rates. As this phenomenon is faster with fully charged batteries, after 2-3 months they would probably have already lost 5% to 15% of their initial load, even if their LSD claims are accurate.

That information would be really valuable, although I understand these tests would involve quite a lot of work.

You also said in your post that you were surprised because the high rate charge test resulted in higher capacities than those of the low rate test. That is not unexpected with new batteries and it's not a result of the charge rate, but a consequence of having performed the low rate test first.

Brand new batteries don't show their maximum capacity until a few charge-discharge cycles, after which their capacity eventually stabilizes. These initial cycles may very slightly decrease the battery life but will also improve their capacity, so they may be well worth to carry out if maximum possible capacity is an important factor for your application.

In fact, as you correctly expected, very high charge rates will decrease the maximum load and, more importantly, reduce battery life too. I've heard that the recommended current intensity to charge this type of batteries would be about 500mA, therefore about 4h charging period.

[Ulfric M Douglas]

Re: TESTED & Necro'd

Thanks for the bump NooB!
I didn't know there was such an excellent review on this site ...
I'm now off to search Captain D's posting history for more thoroughly-investigated gems...

[CaptainD]

[pepper]

[CaptainD]

http://e-group.uk.net/forum/showthread.php?t=12087

Cheers

Chris