# eneloop longevity



## arjay (Aug 15, 2010)

So my location has recently been plagued with power outages and I dread the day that we will lose power for long periods of time (days to weeks). 

I was thinking that if I was to stock up on eneloops to provide power for my flashlights and portable fans I would at least have some power. 

Now if I invest on a 100 of those cells and store them until needed, how long would they last if left unused/sparingly used? 

I've read that NiMH cell can only serve 5-10 years with regular use until they completely deteriorate. Is there any truth to this? I do plan to top them off every month and refresh once of twice a year.


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## Battery Guy (Aug 15, 2010)

Greetings arjay,

100 eneloops? Do you need to power your hot water heater or something? Seriously though, you must have a lot of battery operated devices to need that many cells.

As eneloops are low self-discharge (LSD) NiMH cells, there really is no need to top them off on a monthly basis, since the self-discharge rate is only ~1% per month, unless you want them always to be >99% SOC (state-of-charge).

The tougher question is in regards to longevity, or calendar life of the eneloop. I believe that the eneloops have only been out on the market for just over two years. There is a good chance that even Sanyo does not have real aging data for 5+ years on these. So you need to rely upon anecdotal evidence from users, and a little of what we know about the chemistry differences between the eneloop and "standard" NiMH cells to make an educated guess as to their longevity.

The anecdotal evidence on CPF indicates that users have had very good luck with eneloops over the last two years, with few (if any) going bad even with relatively heavy use.

From a chemistry standpoint, the changes that Sanyo made to the eneloops to reduce self-discharge should actually improved longevity. This includes an improved separator and the elimination of manganese from the metal hydride alloy.

My best "educated" guess is that you will be good with these cells for at least 5 years. My gut tells me that you might get 10 years, but there are too many unknowns to really know.

I hope this helps.

Cheers,
BG


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## Mr Happy (Aug 15, 2010)

Some of us have Eneloops with a manufacturing date of 2006. These 2006 cells still perform quite adequately, having perhaps lost 100 mAh of their original capacity over that time, giving 1850 mAh instead of the expected 1950 mAh or so. However, the 2006 cells in my collection that perform worst are the ones that gathered dust in a warehouse for a long time before being purchased. For all I know those cells were subjected to extreme temperature cycling or some other kind of abuse while in storage.

I suspect that if freshly manufactured Eneloops are cycled once a year and stored in a good environment (perhaps in an air-tight container in a refrigerator) then they will last better.

Note: When 2006 Eneloop packages have been opened for the first time and the cells tested three years after manufacture they have been found to hold a good charge of about 1450 mAh with a very low variation in charge and voltage between cells. (Cells fresh off the production line usually come with a charge of about 1700 mAh.) This compares with garden variety NiMH cells that would usually be found DOA after three years in a warehouse.


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## Lynx_Arc (Aug 15, 2010)

invest in a car charger so you can charge batteries daily if needed and get a few lithium primaries for backup so you won't have to worry about them for 10-15 years unlike having to cycle alkalines due to fear of leakage. I went through a 4.5 day power outage here in 2007 before I had any LSD cells and used up 32 AAs I charged 8 of them every day running errands in my car. I used the same 16 batteries for 4 days just kept recharging them between two lanterns and a few lights and other dim lights using alkalines at that time as the nimh would discharge too much over 6 months to use them. I recommend if you can charge daily having 2.5 times your daily usage of LSD batteries and 2 times primaries. Alkalines would be good but I wouldn't buy more than you use in 2 years of them due to leakage concerns.


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## Burgess (Aug 15, 2010)

Just FYI --


Sanyo Eneloops have been around for 5 Years now.


They introduced their "Eneloop Tones" multi-colored sets (Limited Production)
to celebrate their 5 year Anniversary. (these are the new 1500-cycle design)


I first purchased Eneloops on 07/06/2007, from Circuit City.
These were all manufactured 15 months prior -- in early 2006.

Every single one of these cells *still *performs admirably !

Truly Amazing Performance !


I feel that Sanyo Eneloops are a Revolutionary Product.

Just wish we could buy 'em in their C and D sizes -- in USA.


_


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## arjay (Aug 15, 2010)

Thank you for your input guys. I think I'm one of the first users of eneloops as I got my first pack way back September of 2006 and they are still performing well till now.

I just pulled the trigger on 100 cells plus a maha c9000 to keep those batteries in check. I think I got a good price too, just under 9$ for a pack of 4AA


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## Bones (Aug 16, 2010)

As indicated by Burgess, the Eneloop was announced on 01 Nov 2005 and released to the market on 14 Nov 2005:





Who knew then that almost five years on reports of sub-standard performance and/or failures of any sort would remain virtually non-existent for that rather plain little cell. A stark contrast to its immediate predecessors, the mighty 'high-capacity cells' typified by the Energizer 2500mAh.


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## don.gwapo (Aug 16, 2010)

Hello kabayan,

Wow, 100 pcs. of eneloop. I must say you really want to be prepared. But I agree with you. Power outage is common in our country especially in the provinces, coz that's where I live. It will even took more than a week for the power to restore if a typhoon hits. So 100 pcs. is surely adequate.


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## Arcus Diabolus (Aug 16, 2010)

Hail fellow pinoy! Where do you buy your eneloops? I can never find them in at SM and I only found 1 pair at greenhills. I would suggest you buy a generator for those long outages. I'm from the provinces and have experienced my share of power outages. 100 eneloops, wow thats alot of gadgets, though you'd might want to add some lithium primaries to that just in case.


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## Apollo Cree (Aug 16, 2010)

A smaller number of eneloops, 12 V deep cycle marine batteries, a GOOD smart marine battery maintainer and a 12 V powered NiMH charger will give you MUCH more capacity at a much lower price. Plus it will have the capability of powering higher current devices.


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## arjay (Aug 16, 2010)

don.gwapo said:


> Hello kabayan,
> 
> Wow, 100 pcs. of eneloop. I must say you really want to be prepared. But I agree with you. Power outage is common in our country especially in the provinces, coz that's where I live. It will even took more than a week for the power to restore if a typhoon hits. So 100 pcs. is surely adequate.



I live in the island of Mindanao, we were most unfortunate last summer as we are highly reliant on hydroelectric dams for power. We had 12-18 hours rotating blackouts for two whole months! I expect that to worsen in time as the demand is growing faster than they can put up new power plants. I just want to be prepared. :tinfoil:


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## arjay (Aug 16, 2010)

Arcus Diabolus said:


> Hail fellow pinoy! Where do you buy your eneloops? I can never find them in at SM and I only found 1 pair at greenhills. I would suggest you buy a generator for those long outages. I'm from the provinces and have experienced my share of power outages. 100 eneloops, wow thats alot of gadgets, though you'd might want to add some lithium primaries to that just in case.



I used to get mine at the camera shops at Hidalgo when I was still a student in Manila. But now that I've moved back to my hometown in Mindanao, I found a good source for them online that ships nationwide. I'll shoot you am PM with his contact details. 

I do keep a 10KVA standby genset with about 60 liters of petrol but it's too costly to run unless I want to use the A/C. Also have a stockpile of lithium primaries as my last resort. I like to be prepared. :twothumbs


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## arjay (Aug 16, 2010)

Apollo Cree said:


> A smaller number of eneloops, 12 V deep cycle marine batteries, a GOOD smart marine battery maintainer and a 12 V powered NiMH charger will give you MUCH more capacity at a much lower price. Plus it will have the capability of powering higher current devices.



As much as I would like to go with the deep cycle marine batteries with a GOOD float charger for power, those are close to impossible to source locally. All the "battery specialists" that I've called don't even know what a deep cycle marine battery is. Buying it online and Having it shipped to my location would cost too much as freight charges are crazy expensive here.


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## fishinfool (Aug 16, 2010)

*Kumusta mga Kaibigan!* Hearing about all those power outages in the Philippines brings me back to when I lived there in the 70's and 80's. As kids, we loved typhoons because there was no school for days and loved power outages because we could play outside all day and night long. Now I wanna go back home. It's been waaaaaaay too long. 

Going back to semi-topic, if I had back then, the batteries and flashlights I own now, I would have been King of the World.............
I mean King of Baguio! :twothumbs


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## Arcus Diabolus (Aug 16, 2010)

arjay said:


> ... I'll shoot you am PM with his contact details.
> 
> I do keep a 10KVA standby genset with about 60 liters of petrol but it's too costly to run unless I want to use the A/C. Also have a stockpile of lithium primaries as my last resort. I like to be prepared. :twothumbs


 No need... I can't buy online,:sigh:. Now thats prepared!


fishinfool said:


> *Kumusta mga Kaibigan!* Hearing about all those power outages in the Philippines brings me back to when I lived there in the 70's and 80's. As kids, we loved typhoons because there was no school for days and loved power outages because we could play outside all day and night long. Now I wanna go back home. It's been waaaaaaay too long.
> 
> Going back to semi-topic, if I had back then, the batteries and flashlights I own now, I would have been King of the World.............
> I mean King of Baguio! :twothumbs


 I love typhoons for that too! And the reason to use my flashlights!:candle:


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## ryanandty (Aug 16, 2010)

Hey! A friend of mine grew up in Baguio! He even brought me back a locally made keychain last time he went (totally cheesy, right?). CPF sure does cast a wide net.


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## arjay (Aug 16, 2010)

fishinfool said:


> *Kumusta mga Kaibigan!* Hearing about all those power outages in the Philippines brings me back to when I lived there in the 70's and 80's. As kids, we loved typhoons because there was no school for days and loved power outages because we could play outside all day and night long. Now I wanna go back home. It's been waaaaaaay too long.
> 
> Going back to semi-topic, if I had back then, the batteries and flashlights I own now, I would have been King of the World.............
> I mean King of Baguio! :twothumbs



Typhoons?! I don't need no typhoons to get power outages. Just today we already had two blackouts, one lasting 4 hours and another about an hour. The power grid is just unreliable! You might think that I'm living a flashaholics dream but its gets old fast if you have to endure that every single day. :mecry:

King of the world eh? I think I'm the King of Zamboanga then! I like to go outside with pockets full of flashlights and batteries when the power goes out at night and turn them all on the same time, I get to literally light up our part of the neighborhood. :laughing:


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## Turbo DV8 (Aug 16, 2010)

arjay said:


> Just today we already had two blackouts... _The power grid is just unreliable_!


 
Where's Enron when you really need 'em?


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## etc (Aug 17, 2010)

I have them, dated Sept 2006 and I think I've lost some capacity. I have been running that new Malkoff M31 module and the runtime has not been that great, with some cells I got under 1 hour whereas some got more like 1.5 hours on 2xAA Eneloops.

However with some Eneloops I get greater runtime than with others. So it looks like some cells dropped in capacity more than others. Also I have a few cells that get hotter than others when charging.

I believe NiMH degrades from age, not from number of charges.


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## WDG (Aug 17, 2010)

I use a mix of 76 AA Eneloop cells purchased in 2007 and 2008. The 2007s typically rate from 1850 to 1900mAh, with internal resistances of 1.60 to 1.65VDC. The 2008s typically rate 1900 to 1950mAh, with internal resistances of 1.50 to 1.58VDC. 

Out of all those, I have exactly *one* cell that seems a bit off, rating at 1750mAh. IIRC, the IR was about 1.65VDC on this one. This is also the only cell of the bunch with a slightly dented in base, so I'm guessing it got dropped on its butt.

The 16 AAAs I have are also mixed ages, but nearly all around 840 to 850mAh, with higher IRs from 1.85 to 1.95VDC. 

Seems to me they're aging most gracefully.


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## JET YCOY (Aug 17, 2010)

GOOD TO KNOW NA MAY MGA PINOY DIN PALA DITO. KEEP IT UP! FLASHAHOLICS


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## arjay (Aug 17, 2010)

WDG said:


> I use a mix of 76 AA Eneloop cells purchased in 2007 and 2008. The 2007s typically rate from 1850 to 1900mAh, with internal resistances of 1.60 to 1.65VDC. The 2008s typically rate 1900 to 1950mAh, with internal resistances of 1.50 to 1.58VDC.
> 
> Out of all those, I have exactly *one* cell that seems a bit off, rating at 1750mAh. IIRC, the IR was about 1.65VDC on this one. This is also the only cell of the bunch with a slightly dented in base, so I'm guessing it got dropped on its butt.
> 
> ...



How do you measure internal resistance? Do I need a special device or something?


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## Random Guy (Aug 17, 2010)

WDG said:


> I use a mix of 76 AA Eneloop cells purchased in 2007 and 2008. The 2007s typically rate from 1850 to 1900mAh, with internal resistances of 1.60 to 1.65VDC. The 2008s typically rate 1900 to 1950mAh, with internal resistances of 1.50 to 1.58VDC.
> 
> Out of all those, I have exactly *one* cell that seems a bit off, rating at 1750mAh. IIRC, the IR was about 1.65VDC on this one. This is also the only cell of the bunch with a slightly dented in base, so I'm guessing it got dropped on its butt.
> 
> ...


Resistance is measured in ohms, not volts.


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## Mr Happy (Aug 17, 2010)

arjay said:


> How do you measure internal resistance? Do I need a special device or something?


The readings quoted by WDG would be the initial test voltages reported by the C9000 when you place a battery on charge. This voltage is proportional to the internal resistance of the cell and is a fairly good health indicator.



Random Guy said:


> Resistance is measured in ohms, not volts.


See above.


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## arjay (Aug 17, 2010)

Mr Happy said:


> The readings quoted by WDG would be the initial test voltages reported by the C9000 when you place a battery on charge. This voltage is proportional to the internal resistance of the cell and is a fairly good health indicator.



Wow! that got me excited, I'm expecting a c9000 together with the eneloops I ordered which are due to arrive tomorrow. What else can this amazing charger do? recharge my car batteries?  Seems like I need to get my hands on more of those to keep my 180 eneloops happy and healthy(runs out and sells kidney!)


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## olephart (Aug 17, 2010)

WDG said:


> I use a mix of 76 AA Eneloop cells purchased in 2007 and 2008. The 2007s typically rate from 1850 to 1900mAh, with internal resistances of 1.60 to 1.65VDC. The 2008s typically rate 1900 to 1950mAh, with internal resistances of 1.50 to 1.58VDC.
> 
> Out of all those, I have exactly *one* cell that seems a bit off, rating at 1750mAh. IIRC, the IR was about 1.65VDC on this one. This is also the only cell of the bunch with a slightly dented in base, so I'm guessing it got dropped on its butt.
> 
> ...




I recently bought 8 "new" duraloops from a clown on the b/s/t forum. They turned out to be late 2007 manufacture. The capacity is about what WDG stated (1750-1850), but the voltage sag under load is pretty bad. They spend over half of their run time well below 1.2V with a 500mA load.

Comparing voltage to the various published charts, these cells most closely resemble charts for 5A loads rather than 500mA loads. I don't know if age is a factor or they are used/abused cells.


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## WDG (Aug 18, 2010)

Mr Happy said:


> The readings quoted by WDG would be the initial test voltages reported by the C9000 when you place a battery on charge. This voltage is proportional to the internal resistance of the cell and is a fairly good health indicator.



What he said! 

I didn't even know the MH-C9000s gave this kind of information when I first got them. It was from reading through CPF that I discovered it, and how useful it is. Here's a page that gives a good explanation of what the numbers mean: *Interpreting Maha MH-C9000 Impedance Check Voltage* linked from TakeTheActive's *TTA's Picks for Best Answers to Rechargeable Battery Questions*


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## arjay (Aug 18, 2010)

WDG said:


> I didn't even know the MH-C9000s gave this kind of information when I first got them. It was from reading through CPF that I discovered it, and how useful it is. Here's a page that gives a good explanation of what the numbers mean: *Interpreting Maha MH-C9000 Impedance Check Voltage* linked from TakeTheActive's *TTA's Picks for Best Answers to Rechargeable Battery Questions*



Thanks for the links! seems like I need to do a lot of readings. I just got my c9000 and batteries today. 

Wonder if I should do a capacity test on all of them just to see how consistent these eneloops are. I got 80 AA's and 20 AAA's all with the same production code thus were produced in the same batch. Has anybody performed a test like this with this big of a sample size?


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## fishinfool (Aug 18, 2010)

arjay said:


> Thanks for the links! seems like I need to do a lot of readings. I just got my c9000 and batteries today.
> 
> Wonder if I should do a capacity test on all of them just to see how consistent these eneloops are. I got 80 AA's and 20 AAA's all with the same production code thus were produced in the same batch. Has anybody performed a test like this with this big of a sample size?


 
If you have the time and/or just want to experiment like I do, then go for it. I have over a hundred eneloops and duraloops (accumulated over 8 months though), all of which I've done break-in's right out of the package, used them, charged, discharged and r/a'd them several times, and they all have produced very consistent numbers. 

If you do a capacity test on all of them, I'd love to see the numbers just to compare them to mine. But since you have 100 eneloops I guess we'll see them numbers in about 3 weeks or so.


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## arjay (Aug 19, 2010)

fishinfool said:


> If you do a capacity test on all of them, I'd love to see the numbers just to compare them to mine. But since you have 100 eneloops I guess we'll see them numbers in about 3 weeks or so.



3 weeks? try 3 months. I plan to do discharge>break-in>discharge>break-in on each set to bring them to full capacity. 4days/setx25 =100days  now I can cut that in half if I can get my hands on another c9000 :naughty:


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## fishinfool (Aug 19, 2010)

arjay said:


> 3 weeks? try 3 months. I plan to do discharge>break-in>discharge>break-in on each set to bring them to full capacity. 4days/setx25 =100days  now I can cut that in half if I can get my hands on another c9000 :naughty:


 
When you mentioned doing a capacity test on all of them, I assumed you were just going to do an R/A but since you've explained it further, I guess we'll see you in 3 months. Just make sure to come up for air every now and then. :naughty: Good luck.


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## Apollo Cree (Aug 24, 2010)

arjay said:


> As much as I would like to go with the deep cycle marine batteries with a GOOD float charger for power, those are close to impossible to source locally. All the "battery specialists" that I've called don't even know what a deep cycle marine battery is. Buying it online and Having it shipped to my location would cost too much as freight charges are crazy expensive here.



They might call it something different around there. Maybe just a "Marine battery." Maybe someone who supplies parts for boats would have a better idea. A "gel cell" or "unspillable" battery might have some value as well. 

You might even be better off with just a regular car battery. Realize that every time you give it a really deep discharge, you're shortening the lifetime. If you size it such that you only discharge it part way during an outage, it might work well enough, especially if you only do the deep discharge on rare occasions when you're really desperate. It will eventually go bad. Replace it when that happens. 

If you can't get a good charger, you could just top it off after an outage and rig up some sort of real slow trickle charge circuit and check the water level frequently. 

Consider it this way. An AA eneloop gives you about 2 watt hours. A car battery gives you about 500 watt hours. Consider the relative prices and the amount of work involved to charge the batteries. 

You may also be able to hook the battery up to a car with jumper cables if you have a long outage and charge it that way. 

By the way, be sure to put a fuse right at the battery terminals. Lots of amps, sparks and heat if you have wiring problems.


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## thedeske (Aug 25, 2010)

arjay said:


> 3 weeks? try 3 months. I plan to do discharge>break-in>discharge>break-in on each set to bring them to full capacity. 4days/setx25 =100days  now I can cut that in half if I can get my hands on another c9000 :naughty:



And I thought my Break-In of 16 (for a TK40 - 1 set in the tube & 1 set ready) was tedious.

At one point I thought I had a close guesstimate of 1 hour into trickle charge at the end of the Maha break in.


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## tengc82 (Nov 21, 2011)

You can get AW 18650s from Espinelli in Manila. Just behind Bangko Sentral ng Pilipinas (Central Bank of the Philippines). I think those are more reliable if you have good lights from reputable brands that run on dual CR123s. Longer lasting batts and higher power. Pretty good in a blackout. Sorry to hear about the electricity issue in Mindanao. Never knew it was that bad. The electricity in Manila is great although some people say expensive due to rising oil prices.


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## tengc82 (Nov 21, 2011)

Wow! Nice to know there are Pinoys here in CPF! We should have a meet sometime to discuss our hobby. How many are based in Manila?


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## Wrend (Nov 21, 2011)

In a pinch the C9000 will run nicely off of your car's 12VDC too. 

I have a bunch of Eneloops and use them in series cell sets so that each cell within each set is always used in the same devices as the other cells within that set and has the same cycle life. I store them charged and just switch them in to a device when the set in it gets low. This way the cells within each set are charged at the same time as each other and have the same state of charged capacity even though they may have been in storage in my work room for a while.

Since getting the C9000, I do a slow discharge at 100mA, then a break in cycle on my new Eneloops (1900mAh for the AAs and 800mAh for the AAAs), then match them for capacity. I check the IR by their voltage measurements on my multimeter after they've been fully charged and rested for a few hours by comparing their "battery test" load voltage with their resting voltage. The MM measures down to 1mV, which is nice.

I also calculated the average capacity test variations of the different ports on my C9000 and use that to calculate even more accurate capacity results for the cells I test in it.

This probably isn't something the average user will want to do, but someone with 100 Eneloops might want to consider it.

My cells generally get used in rotation often enough so that I don't worry about doing extra charge and discharge cycles on them to keep them fresh. But in some devices that I use rarely, I like to do a full discharge and charge cycle on the cells about every 6 months when I think of it.

For general charging I charge the AAAs at 400mA and the AAs at the default 1000mA. I also let them go through the top off charge after the first charging phase is done to help balance them off, leaving them on the charger for a total of about 5 hours.

The nice thing about this kind of precision use, as an example: The 4 AAA Eneloops that I've been using for the last couple months on a daily basis in my TI-89 calculator all have the exact same voltage level down to the mV. 

My two year old Eneloops (the oldest ones I have) have only lost about 1.1% of their capacity. They don't have more than about 50 cycles on them and have been used primarily in low drain rate transmitters, but they've been used at up to a 5A drain rate for a few minutes at a time in other devices, and were overcharged and got pretty hot on a dumb charge a few times.

...

Just noticed this thread is kind of old and was resurrected...


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## Bolster (Jun 9, 2012)

...and another resurrection here in 2012. Worthy of it, since the thread documents historical Eneloop performance. I've been using the BI mode on my Maha C9000 to revive my cells and have observed:

2006-vintage Eneloop AAs average 1871 mAh capacity (for 12 cells)
2007-vintage .................................1942 mAh (for 2 cells)
2010-vintage .................................1986 mAh (for 9 cells)
2011-vintage .................................1954 mAh (for 4 cells).

None of these cells stored in refrigerator, and many of them were not sufficiently exercised (I had no Maha to refresh) until now. Many of them were in low-draw applications that would take years to deplete; some were in high-draw flashlights, and many others waiting around in the drawer to be used. So a mix of usages. Without regular R&A or BIM, these cells were not particularly well cared for.


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## HighlanderNorth (Jun 9, 2012)

Bolster said:


> ...and another resurrection here in 2012. Worthy of it, since the thread documents historical Eneloop performance. I've been using the BI mode on my Maha C9000 to revive my cells and have observed:
> 
> 2006-vintage Eneloop AAs average 1871 mAh capacity (for 12 cells)
> 2007-vintage .................................1942 mAh (for 2 cells)
> ...



What is R&A and BIM?


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## Shadowww (Jun 9, 2012)

HighlanderNorth said:


> What is R&A and BIM?



Refresh&Analyze (basically discharges & charges battery few times in a row) and Break-In Mode (charges battery at 1/10 of it's capacity for 16 hours, then complete discharge, then fast charge with dV termination)


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## Bolster (Jun 10, 2012)

Minor point, but I think the second charge of BIM is also 16 hours. The whole process of a Maha BIM takes something like 39 hours.


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## Shadowww (Jun 10, 2012)

Bolster said:


> Minor point, but I think the second charge of BIM is also 16 hours. The whole process of a Maha BIM takes something like 39 hours.



Oops, indeed - my bad!


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## hopkins (Jun 10, 2012)

Eneloop longevity rules. Last winter I placed 2 of them inside D-cell adapter sleeves to power one of those Harbor Freight electronic bug zappers
(looks like a tennis racket) to go after a big spider on the ceiling. Now 5 months later I needed to rid the patio of some wood wasps and thought to dig
the zapper out of a forgotten drawer. Bingo! The charge was still good and did the wasps in. One touch and they fall to the ground dead.


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## Trevtrain (Jun 10, 2012)

Bolster said:


> ...and another resurrection here in 2012. Worthy of it, since the thread documents historical Eneloop performance. I've been using the BI mode on my Maha C9000 to revive my cells and have observed:
> 
> 2006-vintage Eneloop AAs average 1871 mAh capacity (for 12 cells)
> 2007-vintage .................................1942 mAh (for 2 cells)
> ...



Hi Bolster :wave:

Not to be picky here but what would be interesting to know (even despite the small sample size) is not just the average capacity but whether there was much variation between cells. Did you keep the actual figures on each cell by chance? I would consider this info arguably even more important than the average figures though perhaps negated a little by the varying usage applications they've had.

It certainly seems that Eneloops are getting some good history behind them (nearly 6 years now), though I've only had mine for about two.

Cheers


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## Bolster (Jun 12, 2012)

Trevtrain said:


> Not to be picky here but what would be interesting to know (even despite the small sample size) is not just the average capacity but whether there was much variation between cells.



Excellent point, why didn't I think of that? 

Standard deviation for: 
2006 Eneloops ....................... 89 mAh
2007 Eneloops (sample size of 2 too small)
2010 Eneloops ....................... 19 mAh
2011 Eneloops ....................... 16 mAh

So, from 2006, my best is cranking out 1972 mAh, and my worst, 1645. (1500 is my unofficial "toss" number.) Sadly, I have no idea how these two cells were treated differently. Perhaps one had regular exercise and the other has been sitting. I've only recently come to the gospel of labeling cells and doing bi-annual maintenance. And I'm still not at the level of zealotry I'm recording which cells get assigned to what duties. But certainly there must be someone here who has that depth of interest.

For the record, if I drop my worst two cells from 2006, the SD = 45.


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## apagogeas (Jun 12, 2012)

Is this the first evidence that eneloops do suffer after all? Probably a tortured cell, after "only" 6 years managed the worst 1645... That makes me think a 10 year useful life is easily achievable, especially considering the other cell don't show any signs of degradation. Now I try to think of any other battery I have used that long in the past and I can't think of any. Eneloops must be declared the king battery of the decade for sure!


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## czAtlantis (Jun 12, 2012)

I just bought new packages of eneloops. First package was manufactured 01/2012 and second one 12/2010 (old stock :mecry. Let's say the second one was 01/2011.
Initial capacities from Maha at 500mA discharge
01/2012: 1275, 1276, 1277, 1271mAh. 
12/2010: 1379, 1376, 1376, 1375mAh.
Assuming they were manufactured the same way and charged to the same level they have ~100mAh difference...this pretty good for one year storage.


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## Wrend (Jun 13, 2012)

Standard capacity test would be closer to 400mA. If they've been sitting for long enough their internal resistance/impedance probably has gone up a bit. Cycling them a few times or doing the break in on them after discharging should help with that.

When I get mine, I actually do a 100mA discharge first, then the break in at 1900mAh to measure their capacity potential.

Even being older stock, they'll likely have a similarly long and useful life when compared to newer stock.

Oh, and it looks like you swapped the dates by mistake.


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## czAtlantis (Jun 13, 2012)

Yeah, I swapped them, sorry 
After break-in those older ones have standard capacity around 1980mAh so everything looks OK


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## Bolster (Jun 13, 2012)

Wrend said:


> I actually do a 100mA discharge first,



You're a patient man! Why so slow? Does it help?


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## Wrend (Jun 13, 2012)

I have 2 C9000s to help with the workload, but these days I have enough extra sets charged and ready to use. I only buy more now if I get down to only one extra set. I'm never really waiting for anything to charge any more, or whatnot.

I discharge at a slower rate before the break in because it might be a little easier on cells with higher internal resistance and more importantly that it likely helps to cycle the cells more, discharging them deeper than they would be at a faster rate, helping to refresh their performance potentials perhaps just a little more.


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## mousewizard (Jun 19, 2012)

arjay said:


> 3 weeks? try 3 months. I plan to do discharge>break-in>discharge>break-in on each set to bring them to full capacity. 4days/setx25 =100days  now I can cut that in half if I can get my hands on another c9000 :naughty:



That's why I have 11 of them...


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## apagogeas (Jun 20, 2012)

With a bit of planning ahead, one MC-9000 is enough for all the tasks. I have about 20AA and a few more AAA, half are drained in about 2-3 weeks usage. The rest are in remotes which can easily wait months to be charged. I make a habit to estimate how much time needed for a battery to be completely drained and I schedule a recharge at half of that time, so e.g. if my wireless mouse eats up the batteries in 1 month, these batteries will be charged around every 2 weeks, so not to run out of power if a delay occurs. Any regular charging is usually performed at the weekend, the rest of the days are reserved for lengthy tasks such as break-ins or testing. There are times my maha works for a full week. Now if I have needs to charge an application more often than 2 days, I have always a set of spare LSD to keep going. I don't know what would be the case if I had 40-50AA but I think one charger wouldn't be enough really! 11 maha chargers??? That needs a dedicated desk to put them on! Can you post a photo of these together??


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## Bolster (Jun 20, 2012)

IIRC, Mouse is set up to run a battery reconditioning business.


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## mousewizard (Jun 21, 2012)

apagogeas said:


> I don't know what would be the case if I had 40-50AA but I think one charger wouldn't be enough really! 11 maha chargers??? That needs a dedicated desk to put them on! Can you post a photo of these together??



Sure. I had to unpack everything and set up a demo display because I'm done with my Solstice charging cycle. I top off my LSD batteries on each Solstice and top off the hi-cap batteries every 90 days. Between those times the gear is stored in faraday cages. But I understand the need to see. I'm a newbie to the forum and might be full of shite. 

Anyhoo... here's the setup in its full glory. In reality I only run 8 chargers at a time and three are kept as backups. All are run off DC from my solar rig, hence the DC distribution bus and customized power cables. I only put one battery in each charger because that's about what I had lying around on the bench. The rest are in storage. No; you can't see my storage.


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## czAtlantis (Jun 21, 2012)

Wow, why you need so many chargers anyway?

Btw - have you tried if those Maha chargers charge exactly the same at different input voltages? I mean if results (reported capacity from same cell) at 11V and 14V are identical.
And also if results are affected by number of cells in charger - I mean if you charge/discharge one single cell in charger and when the charger is charging/discharging full 4 cells.
Thanks


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## mousewizard (Jun 21, 2012)

I'm a survivalist. One of my post-collapse businesses will be bartering and charging AA/AAA batteries. So I have a stockpile of AAs and AAAs that need to be consistently refreshed. Post-collapse I'll need those chargers because part of the business model is people bringing me batteries to charge or to trade and I need to be able to cover all the bases as well as satisfy a non-trivial demand level. So I have solar panels and big batteries and inverters and hobby chargers and of course these.

No, I haven't done the "different input voltages" test. My system puts out 13.2 volts for a very long time so I'm not too worried there. When I was doing my research into these chargers, I found that others have confirmed the manufacturer's claim: Each cell is individually managed by the microprocessor, so one cell or four cells doesn't matter.


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## Wrend (Jun 21, 2012)

mousewizard said:


> ...No; you can't see my storage.



Makes me curious. Might be kind of interesting. But fair enough.


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## vikaden (Jun 22, 2012)

Just got some new Eneloops and a C9000, wanted to post my discharge and break-in results. Only have the first 4 done so far, they were discharged at 100mA and then a break-in was done.

Date BIM
01/12 2012
01/12 1999
01/12 1978
01/12 1986
01/12 1987
01/12 1985
01/12 1965
01/12 1978
01/12 2015
01/12 2019
01/12 2011
01/12 2008


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## tickled (Jun 24, 2012)

I recently cracked open a package of re-branded first gen Eneloops. Package is marked 2008, purchased in September or October of 2009.

After one R&A cycle on the C9000, I had capacities of around 1770mAH for one pair and closer to 1810mAH for the other two and I think impedance check of (?) of 1.6 to 1.65.

Charge rate 1000mAH, discharge rate 500mAH. I'm running another cycle right now!


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## wshyang (Jun 24, 2012)

mousewizard said:


> I'm a survivalist. One of my post-collapse businesses will be bartering and charging AA/AAA batteries. So I have a stockpile of AAs and AAAs that need to be consistently refreshed. Post-collapse I'll need those chargers because part of the business model is people bringing me batteries to charge or to trade and I need to be able to cover all the bases as well as satisfy a non-trivial demand level. So I have solar panels and big batteries and inverters and hobby chargers and of course these.



I'm really trying to work out if you are serious or if this is a troll post, lol.


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## Shadowww (Jun 24, 2012)

wshyang said:


> I'm really trying to work out if you are serious or if this is a troll post, lol.



Considering he truly has 11 chargers, I guess his post is completely serious.


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## wshyang (Jun 24, 2012)

tickled said:


> I recently cracked open a package of re-branded first gen Eneloops. Package is marked 2008, purchased in September or October of 2009.
> 
> After one R&A cycle on the C9000, I had capacities of around 1770mAH for one pair and closer to 1810mAH for the other two and I think impedance check of (?) of 1.6 to 1.65.
> 
> Charge rate 1000mAH, discharge rate 500mAH. I'm running another cycle right now!



Oh dear, I have quite some from 08 and some from 06 even. So these things don't fare too well when in storage?


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## Shadowww (Jun 24, 2012)

tickled said:


> I recently cracked open a package of re-branded first gen Eneloops. Package is marked 2008, purchased in September or October of 2009.
> 
> After one R&A cycle on the C9000, I had capacities of around 1770mAH for one pair and closer to 1810mAH for the other two and I think impedance check of (?) of 1.6 to 1.65.
> 
> Charge rate 1000mAH, discharge rate 500mAH. I'm running another cycle right now!


You should try break-in (if you don't have much time then single 2000mAh break-in, if you can wait then first 1900mAh break-in and after that 2000mAh break-in), I've noticed that it restores capacity much better than R&A on LSD batteries.
Don't forget to discharge batteries before doing a break-in, some members here saw noticeable mAh gain by doing that.


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## mousewizard (Jun 24, 2012)

wshyang said:


> I'm really trying to work out if you are serious or if this is a troll post, lol.



Oh, I'm serious. http://www.candlepowerforums.com/vb/showthread.php?339573-Doomer-Lead-Acid-Charger&highlight=


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## tickled (Jun 25, 2012)

Shadowww said:


> You should try break-in (if you don't have much time then single 2000mAh break-in, if you can wait then first 1900mAh break-in and after that 2000mAh break-in), I've noticed that it restores capacity much better than R&A on LSD batteries. Don't forget to discharge batteries before doing a break-in, some members here saw noticeable mAh gain by doing that.


 The second R&A just wrapped up and it improved: 1880, 1877, 1893, and 1866 were the numbers that I had. I will do one more within the next few days and see what the numbers look like then.


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## tickled (Jun 25, 2012)

tickled said:


> The second R&A just wrapped up and it improved: 1880, 1877, 1893, and 1866 were the numbers that I had. I will do one more within the next few days and see what the numbers look like then.


 I did a discharge and then immediately started another R&A after while the batteries were still warm (I was in a rush) and the impedance check was in the 1.4 range with final capacities ending up at 1866, 1867, 1875, and 1845.


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## Shadowww (Jun 25, 2012)

Do a 100mA discharge & after that a 2000mAh break-in, you'll be surprised


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## tickled (Jun 28, 2012)

Shadowww said:


> Do a 100mA discharge & after that a 2000mAh break-in, you'll be surprised


 1907, 1895, 1907, 1886. Slightly better.


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## Bolster (Jun 29, 2012)

Adding a "research note" here. I've been using the Burn In Mode to revive some old cells, and by BIMing some with reduced capacity at 1900mAh, I think I've been killing them off. Noticing reduced capacity after each BIM. Likely culprit: setting 1900 as capacity, instead of 1600 or 1700 as appropriate. 

Posting this so people don't make the same mistake I did. More info at the "Dying Eneloop" thread, if you're interested.

Based on what I know now, I'd never BIM at 2000 or even 1900 for old cells, until I had a better fix on their capacity. If rehabilitating old cells, start your BIM on the low side. Maybe 1500.

Two, and possibly three, Eneloops were murdered to bring you this information.


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## TyJo (Jul 8, 2012)

Wrend said:


> Makes me curious. Might be kind of interesting. But fair enough.


Haha i'm curious too, as probably everyone is that is looking at this thread.


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