1. I was told that the Sanyo eneloop cells were not 100% fully charged when they leave factory. This makes sense because new cells are fast-charged in the factory to save time. In order to avoid problem with heat and gas built-up, they cannot be charged to 100%. I have tested some eneloop cells that were manufactured 20 months ago, and they still maintained about 70% charge. On the other hand, cells manufactured 6 months ago contain about 75% charge. This confirmed that the discharge rate is much lower than I previously estimated.
2. The self-discharge rate of eneloop (and other LSD cells) is not linear! My own testing showed that a fully charged eneloop may lose 10% of its initial charge during the first month of storage, but in the second months it may lose just 2-3%. The rate becomes even slower after three months. In fact, my 5-month self-discharge test using various brands of LSD cells gave nearly identical results as my previous 3-month test.
3. When an eneloop cell is freshly charged, its capacity actually measures at about 5% higher than its rated capacity (2100mAh vs. 2000mAh). In my previous tests, I used measured capacity as base to calculate the percentage loss. This results in apparently higher percentage loss. Had I used the rated capacity as base value, the self-discharge rate would be about 5% lower.
Based on the above revelation, I believe Sanyo's claim about eneloop (maintain 85% charge after one year, 80% after two year) to be accurate. Therefore the title of my previous review ("The News of LSD Has Been Slightly Exaggerated") has to be replaced.
Over the past two years, I have tested several different brands of LSD cells available from Amazon.com, including . They have all performed very well - practically no difference from the Sanyo eneloop. So the bottom line is: just pick which ever brand of LSD cell is on sale, and you can't go wrong.
[Update on April 21, 2011]
- After testing and using various brands of LSD cells over the past four years, Sanyo eneloop cells have proven to be the most reliable and consistent of them all. I now have to recommend Sanyo eneloop over all others brands.
- Recently Amazon started to offer the cells, at around 25% higher price. In my testing, the improvement of the new eneloop over the original is hardly noticeable. So you'll have to decide whether it is worthwhile to pay the extra cost.My original review below was written back in 2007, when the Sanyo eneloop first became available
through Amazon.com. Part of my initial estimation about eneloop's self-discharge rate turns out to be inaccurate. Please see my other Amazon spotlight review for updated information.
[Original Review follows]
According to Sanyo, the new eneloop LSD (low self-discharge) NiMH batteries can maintain 85% of its original charge after 1 year of storage. This claim is slightly misleading, because it is based on simulation test at 20 degree C. At higher temperature, the self-discharge rate is likely to be much higher.
I have tested five of those AA cells (details are given in my review for the eneloop 4-pack). The average energy loss is about 26% after less than 6 months of storage, based on manufacturer date codes. This self-discharge rate is about 3 times higher than what Sanyo claimed. However, it is still 6 times lower than that of ordinary NiMH batteries. Therefore I'm in the process of replacing most of my existing rechargeable cells to the Sanyo eneloop.
Thanks to lower self-discharge rate, you'll discover a lot more applications for eneloop cells in your house, such as in clocks and remote controls. Do NOT use those cell in smoke detectors, since their discharge voltage profile is very different from that of alkaline cells. Also, don't use them as emergency flash lights batteries in your car, because the higher temperature during summer time will probably nullify the advantage of LSD.
[Update on Jan 13, 2007]
I have tested six new eneloop AAA cells, dated "2006-06'. The average residue charge is 589mAh, and the freshly charged capacity is 827mAh. This implies a self-discharge rate of 29% in 7 months, which is consistent with the rate for AA cells (26% loss in 6 months).
[Update on Jan 29, 2007]
The Rayovac "Hybrid" rechargeable NiMH batteries are now available at Walmart, priced at only $[...] for 4-pack of AA or AAA cells. It is also advertised to have low self-discharge rate, but not as low as that for eneloop. The eneloop is supposed to retain 85% charge in 12 months (when stored at 20 degree C), whereas Hybrid is supposed to retain 80% charge in 6 months (no mention of temperature)
I received several sets of Eneloops in February and label told they
were produced in April - so they sat at warehouse for nine month. I put
them into camera and they worked just fine. Kudos Sanyo!
I should also mention that Sanyo includes reusable battery holders with each set of four. These holders do not look very sturdy, but they perfectly usable.
Technically, Sanyo solved the main problem with NiMh technology - frightening self-discharge rate (up to 40% a month for standard cells). By doing this Sanyo reduced cell capacity down to 2000 mAh from today's top line of 2700 mAh.
Simple calculation shows that due to self-discharge a good 2700 mAh battery holds only around 2000 mAh after a month and a half.
So the answer to the question "which battery is better - Eneloop or standard NiMh" - lies in the usage pattern.
If you always keep batteries in your camera in top-notch charged condition, then standard 2700 mAh set is a winner. For occasional shooters who always forget to charge batteries (like me), Eneloop makes lot of sense because in three month I get around 1900 mAh out of Eneloop and only 1400 mAh from the standard cell. So Eneloop is a winner for everyone who keep batteries inside the camera or any other device for more than 6 weeks.
And, well, if paragraph above looks too technical with too many details and numbers - then Eneloop is a clear winner too, because it just behaves the way battery should behave - without forcing users to know how it works.
This observation made me buy additional sets of AAA Eneloops to use in my wireless mouse, keyboard, voice recorder and LCD flashlight. It should be taken into account that Eneloops are four times more expensive than Alkaline cells, so it is reasonable to use them for devices that require fresh batteries at least twice a year. What are you looking for in a rechargeable battery? Long life? Easy recharging? Excellent performance over the years?
Check, check & check.
I've been using these for over 2 years and they still perform like they are brand new. They're used in Xbox controllers, TV remotes, etc. We use them until they are completely dead then stick em in the Sanyo charger. The charger can hold up to 4 AA batteries. You have to have 2 batteries in together in order for the charger to work. There are 2 independent charge indicators. The green LED flashes when its charging, then turns sold green once they are fully charged.
Take a look at how many of your devices use AA or AAA batteries and then order the total number plus some extra. It might seem like a lot of money up front but if your kids play Xbox you know how fast those batteries die - I probably made my money back in saved battery purchases in 2 months. Of all the rechargeable 'AA' batteries I've used in the past 10 years, these are the only ones that haven't died and continue to hold a charge for extraordinary amount of time.
With the extremely low discharge rate, I even put them into wall clocks and the clocks run for many months. They're my favorite rechargeable batteriesHave used the charger and batteries for over three months now with no loss of performance or any problems of any kind. We use the batteries to run a various appliances and radios. Shipping was fast and the order was without any problemsI'm a photographer and of course prefer to shoot with a dslr, but I have this and another 4 pack of batteries that came with the designed charger. They always work for me, last a long time, and definitely hold a charge. I've owned them since 2009 and get lots of pops in an external camera flash, or hundreds of pictures or lots of video on one charge. Definitely a reliable rechargeable battery.
I should also mention that Sanyo includes reusable battery holders with each set of four. These holders do not look very sturdy, but they perfectly usable.
Technically, Sanyo solved the main problem with NiMh technology - frightening self-discharge rate (up to 40% a month for standard cells). By doing this Sanyo reduced cell capacity down to 2000 mAh from today's top line of 2700 mAh.
Simple calculation shows that due to self-discharge a good 2700 mAh battery holds only around 2000 mAh after a month and a half.
So the answer to the question "which battery is better - Eneloop or standard NiMh" - lies in the usage pattern.
If you always keep batteries in your camera in top-notch charged condition, then standard 2700 mAh set is a winner. For occasional shooters who always forget to charge batteries (like me), Eneloop makes lot of sense because in three month I get around 1900 mAh out of Eneloop and only 1400 mAh from the standard cell. So Eneloop is a winner for everyone who keep batteries inside the camera or any other device for more than 6 weeks.
And, well, if paragraph above looks too technical with too many details and numbers - then Eneloop is a clear winner too, because it just behaves the way battery should behave - without forcing users to know how it works.
This observation made me buy additional sets of AAA Eneloops to use in my wireless mouse, keyboard, voice recorder and LCD flashlight. It should be taken into account that Eneloops are four times more expensive than Alkaline cells, so it is reasonable to use them for devices that require fresh batteries at least twice a year. What are you looking for in a rechargeable battery? Long life? Easy recharging? Excellent performance over the years?
Check, check & check.
I've been using these for over 2 years and they still perform like they are brand new. They're used in Xbox controllers, TV remotes, etc. We use them until they are completely dead then stick em in the Sanyo charger. The charger can hold up to 4 AA batteries. You have to have 2 batteries in together in order for the charger to work. There are 2 independent charge indicators. The green LED flashes when its charging, then turns sold green once they are fully charged.
Take a look at how many of your devices use AA or AAA batteries and then order the total number plus some extra. It might seem like a lot of money up front but if your kids play Xbox you know how fast those batteries die - I probably made my money back in saved battery purchases in 2 months. Of all the rechargeable 'AA' batteries I've used in the past 10 years, these are the only ones that haven't died and continue to hold a charge for extraordinary amount of time.
With the extremely low discharge rate, I even put them into wall clocks and the clocks run for many months. They're my favorite rechargeable batteriesHave used the charger and batteries for over three months now with no loss of performance or any problems of any kind. We use the batteries to run a various appliances and radios. Shipping was fast and the order was without any problemsI'm a photographer and of course prefer to shoot with a dslr, but I have this and another 4 pack of batteries that came with the designed charger. They always work for me, last a long time, and definitely hold a charge. I've owned them since 2009 and get lots of pops in an external camera flash, or hundreds of pictures or lots of video on one charge. Definitely a reliable rechargeable battery.
Tidak ada komentar:
Posting Komentar