Eneloop charging, how full?

[bleagh]

I recently used BREAK-IN mode with my C-9000 on some AAA Eneloops (new version). It reported capacities from 810 to 840. I then let the batteries sit for about a week and discharged at 0.2 amp and get capacities of around 775.

So after only a week, the AAA Eneloops were already down 3% from rated capacity and more than that from actual capacity!

This has me wondering if maybe a fuller charge (800+) has a higher initial self discharge than a lessor charge?

For example, break-in charges to 810-840, normal C-9000 charge with 2 hour topoff charges to 804-822, my MQN05 charges to 788-807. What I am wondering is will the higher charges still be higher after a week or so? Or will they all discharge to about the same after a week? Anybody tested this?

I often don't use freshly charged batteries for a week or more, and even when I do get put in a device, that device my get little or no use for a week or more! So it makes no sense to get maximum charge into the batteries if it just loses it withing the first few days...

Guess I need to do more testing huh?

 

[Wrend]

This has me wondering if maybe a fuller charge (800+) has a higher initial self discharge than a lessor charge?

Yes, it does. The self discharge rate of Eneloops exponentially decreases over time relative to their charged capacity.

They still hold quite a lot for a long time though.

http://www.eneloop.info/uploads/pics/discharge_new_eneloop_06.jpg

I would continue to fully charge your cells. Some of the initial charge will most likely discharge off regardless of how full you charge the cells as the cells reach their resting equilibrium; just a little more so if you fully charge them.

For this reason (as well as others), I prefer to use cells that have been charged and used in battery sets (groups of cells that are used together in series).

I have extra Eneloop sets that I leave charged to use when I need them, and use the ones that were charged least recently.

This may be a bit much for the non-eccentric-battery-enthusiast, so probably just using the least recently charged cells, and checking their capacities a few times a year to make sure they're similar when used together should go a long way.

 

[Smells_Familiar]

This is somewhat related to the OP's post, so I'll throw this in this thread instead of starting a new one.

I just bought 3 new four packs of the new and improved AA eneloops from TD. According to their wrappers they were manufactured in February 2011 (wrapper says 11 02 AO). I performed a discharge cycle on the C9000 for the batteries in one pack so far and came up with these capacities:

1454
1464
1457
1455

These seem very low to me. I know I've read on here that eneloops never come fully charged, but this is as low as 73% capacity after only four months! Sanyo's site says they should retain ~90% after six months. Even if they were only charged to 1900 at the factory this is still only 77% retained capacity after four months.

I decided to do the discharge first to confirm that these are genuine Sanyo made batteries because I've never seen anyone else sell the 1500 cycle Eneloops with the blister packaging that Thomas Distributing carries; plus the fact that Sanyo's own website states that all new "improved" 1500 cycle eneloops come in packaging that specifically states "Up to 1500 Times", and no where on the packaging that my batteries came in does it say that. TD has the packaging pictured on their website that Sanyo's site does, but the batteries came in different packaging.

Now I'm not accusing TD of selling fake eneloops, and I've read their response to another posters questions regarding some of the same issues. However, I've never seen anyone address the incorrect wording on the packaging (according to http://www.eneloop.info/home/the-new-improved-eneloop.html). The wording on the packaging, the packaging itself, and the low retained capacity make me a bit suspicious. The batteries themselves look legit.

Can anyone help me out? Is it normal for these batteries to loose this much charge in this little of time? If so, and if they're genuine Sanyo Eneloop, I'd say this is very deceptive marketing. I've called Mr. Shen (?spelling) at Sanyo's eneloop division, but I had to leave a voice mail. I also called TD but it was after their business hours and I'll try back tomorrow. Hopefully Mr. Shen gets back with me soon.

 

[planex]

I did a discharge on my newly purchased 1500 cycle eneloops. I purchased the eneloop's and the C9000 charger early this week from Amazon. Date code on the eneloops is 12-2010. I used the standard 500 mah discharge rate and got similar capacities to your batteries, so I think they are in the ballpark. After doing the first break-in, I got right at or just slightly below 2000 mah for all 4 cells, so I am happy with them.

 

[Wrend]

They're only pre-charged to about 75% to 80% capacity. Standard discharge capacity test rate is 0.2C/h, since capacity is somewhat relative to discharge rate. For Eneloops AAs that is 400mA.

 

[Smells_Familiar]

Thanks for the replies guys!

I discharged at 500ma just by guess. I'm still wondering why the packaging doesn't say "Up to 1500 Times" like that Sanyo website says it should. Maybe the person who edited that site was ignorant about the batteries at one time being packaged in a different way. I also wonder why TD doesn't picture the exact batteries/packaging on their site that they actually sell. Creates a bit of confusion...

 

[Bullzeyebill]

Smells Familiar, not sure what your issue is. Did you charge up and do a discharge? What are your results? Not really sure why you are having this confusion? You aren't trolling here are you? Just checking. :)

Bill

 

[Lynx_Arc]

Thanks for the replies guys!

I discharged at 500ma just by guess. I'm still wondering why the packaging doesn't say "Up to 1500 Times" like that Sanyo website says it should. Maybe the person who edited that site was ignorant about the batteries at one time being packaged in a different way. I also wonder why TD doesn't picture the exact batteries/packaging on their site that they actually sell. Creates a bit of confusion...

Discharging at 500ma rate will give you a lower capacity reading than 100-200ma. If you think about it, 1500 times is almost insane that is charging them daily for over 4 years while most people only charge batteries on average once a week which would make for 28 years. I seriously doubt that someone would be using the same batteries 28 years later.

 

[Smells_Familiar]

Smells Familiar, not sure what your issue is. Did you charge up and do a discharge? What are your results? Not really sure why you are having this confusion? You aren't trolling here are you? Just checking. :)

Bill

Huh? Definitely not trolling...no desire and it would be just a waste of precious time. Never even thought of that and I've never been accused of that in years of posting on forums. I thought (and think) that I explained exactly what my concern was very thoroughly in my first post in this thread. I discharged the new batteries and I posted results. Could you explain exactly why your confused please. No offense, but I think I was very thorough in my first post. Once again, I bought some new "improved" 1500 cycle batts from TD and imediatly preformed a discharge via the C9000. I posted my results for the 4 batteries I preformed the discharge function on above. And I posted my exact concern and reasons for concern. Why the confusion?

 

[Smells_Familiar]

Discharging at 500ma rate will give you a lower capacity reading than 100-200ma. If you think about it, 1500 times is almost insane that is charging them daily for over 4 years while most people only charge batteries on average once a week which would make for 28 years. I seriously doubt that someone would be using the same batteries 28 years later.

Like Wrend said above, the standard discharge capacity test rate is 400mA. I discharged @500mA by chance....so pretty close by my layman's perspective.

By saying what you wrote in your quote above, are you saying that we shouldn't hold manufactures of products to their claims? Because that's exactly how your reply reads.

I guess I'm feeling some hostility from established forum members after posting just 2 times, and to me it really seems unfounded and unwarranted.

 

[Wrend]

Your listed pre-charged capacity test results should be good and within what is expected.

I have an MH-C9000 as well, and a bunch of the newer 1500 AA Eneloops from TD that I got recently that are still waiting for their discharge and break in on the C9000.

I'm waiting on a cycle to finish right now on some other cells. When that's done, I'll discharge a set of 4 at 500mA to compare capacities with your results. But as I said, it's been my experience that they don't leave the factory fully charged. This may give them a somewhat better long term shelf-life in relation to cell health as apposed to having a higher initial usable capacity would. (Not really sure on that though; just a guess.)

The packaging I recently got my AAs and AAAs in does specifically mention the 1500 cycles, or that they can be recharged up to 1500 times though. You said the cells look fine. I assume they have the crown symbol on them?

 

[Lynx_Arc]

Like Wrend said above, the standard discharge capacity test rate is 400mA. I discharged @500mA by chance....so pretty close by my layman's perspective.

By saying what you wrote in your quote above, are you saying that we shouldn't hold manufactures of products to their claims? Because that's exactly how your reply reads.

I guess I'm feeling some hostility from established forum members after posting just 2 times, and to me it really seems unfounded and unwarranted.

I stand corrected then, as when I got my BC900 some was testing at 200ma discharge which probably gives slightly bigger capacities than 500ma.

 

[Napalm]

Them chargers should have a switch with rare/medium/well done positions.

Nap.

 

[Marc999]

Thanks for the replies guys!

I discharged at 500ma just by guess. I'm still wondering why the packaging doesn't say "Up to 1500 Times" like that Sanyo website says it should. Maybe the person who edited that site was ignorant about the batteries at one time being packaged in a different way. I also wonder why TD doesn't picture the exact batteries/packaging on their site that they actually sell. Creates a bit of confusion...

Nominal Capicity: 2000 mAh / Minimum Capacity: 1900 mAh
Charged from Factory: 75 - 80% [.75 x 2000 = 1500, .80 x 2000 = 1600]

Let's assume 75% capacity charge, your readings of 1450+ mAh seem quite good after ~ 4-5 months from date of manufacture. Using your figures, you've lost less than 50 mAh during this time period.
As above poster mentioned, if you had used 400 mA discharge rate, you'd witness an even higher capacity measurement.

400 mAh being 20% [.2C] of a 2000 mAh battery. This is how a 'standard' capacity is measured.


I'm sure others can explain better, that's my take on the matter. End result: there's nothing wrong with your batteries. By the way, do they have little crowns on the battery labels of each battery? That would indicate the newer eneloop release.

Marc

 

[Smells_Familiar]

Thanks for the helpful replies guys!

Yup, they look identical to what they're supposed to look like, crown, model #, physical appearance and all. It's just the packaging and the initial discharge capacity that had me a bit worried. I didn't know they were only charged ~75% at the factory. If that's the case then my batteries are fine.

@Wrend: Thanks man, I look forward to your results.

The batteries I received do say "Improved 1500 Cycles" on the packaging, not the "Up to 1500 Times" that that Sanyo site I linked to says it should say. That, the fact the blister packaging looks straight up cheap (in my opinion) and unlike something I would expect Sanyo to approve, plus the discharge results all made me a bit suspicious that the batteries might be counterfeit. But like I said, the batteries themselves look legit and I guess are performing like eneloops usually do according to you more knowledgeable forum members. I'm guessing that whoever edited that "The New and Improved" eneloop page I linked to just overlooked that the 1500 cycle eneloops might have been packaged in different packaging at one time???

I'm not picking on TD or trying to be annoyingly anal...$30 isn't a big deal one way or the other to me....but when I'm trusting my life to these batteries while caving and when I know there have been many counterfeit eneloops produced in the past, I pay attention to details.

 

[Murray B]

The capacity is generally given at the 10 hour rate and will generally decline for greater loads. In my experience the rating is also some kind of theoretical maximum and none of my cells has ever delivered as much or more than the rated capacity. Let us say it is "up to" that value which means the acual value is less than or equal to the rating. Same for number of recharges. In nearly forty years I have yet to see 500 cycles from a nickel cell except when they are completely discharged regularly as in a cordless shaver.

 

[Marc999]

Thanks for the helpful replies guys!

I'm not picking on TD or trying to be annoyingly anal...$30 isn't a big deal one way or the other to me....but when I'm trusting my life to these batteries while caving and when I know there have been many counterfeit eneloops produced in the past, I pay attention to details.

You're good to go. I've purchased a couple mh-c9000s from TD as well as some eneloops. He's a reputable dealer as per other's recommendations of his products. Whereas, Ebay or DX could be a gamble. I'd be initially suspicious of different packaging as well, yet I think Sanyo has a wide variety of blister packs per region.
Even mh-c9000s can apparently have different variances from one another, resulting is slightly different capacity measurements, as Mr. Happy suggested to me awhile back. Have fun in the caves, say hi Gollum for me!

 

[Wrend]

...
In my experience the rating is also some kind of theoretical maximum and none of my cells has ever delivered as much or more than the rated capacity.
...

While generally I agree with this assessment, new, fully charged Eneloops typically meet or exceed their labeled capacities (1900mAh minimum for AAs, and 800mAh for AAAs) at least.

...

...
@Wrend: Thanks man, I look forward to your results.
...

Welcome, and here they are:

All cells are date stamped 11-02AO.

Discharged at 500mA:

Cell 1 (1452mAh)
Cell 2 (1470mAh)
Cell 3 (1453mAh)
Cell 4 (1464mAh)
Average (1459.75mAh)

Just out of curiosity, I also discharged another new set of 4 cells at 400mA.

Those results:

Cell 1 (1451mAh)
Cell 2 (1469mAh)
Cell 3 (1456mAh)
Cell 4 (1467mAh)
Average (1460.75mAh)

 

[vali]

Don't worry about those being fake. The initial discharge numbers you got are the right ones for legit eneloops. One of the first eneloop tests I saw in the internet said exactly the same about not being so good with self discharge, but it seems he received a letter from sanyo stating about the 75% charge.

[May 2007 Update: According to Sanyo, Eneloops are only charged to about 75% capacity at the factory. This implies that the battery lost almost no capacity between the factory and my workshop.]

[September 2007 Update: I've just purchased an 8-pack of Eneloops that were manufactured in October 2006. I performed the same initial-discharge test on these and found them to have a capacity of 1316 mAh, which works out to about 72%. The fact that six month old Eneloops come out of the package with 74% capacity and eleven month old ones with 72% suggests that they discharge extremely slowly from the 75% initial charge.]

Source: http://www.stefanv.com/electronics/sanyo_eneloop.html

If they were fakes then they would be discharged or almost discharged and the differences from sample to sample would be bigger (I think one of the great things about eneloops are consistency).

 

[Smells_Familiar]

Quick update: Mr. Shen (sp.?) returned my phone call promptly and left a very kind and thoughtful message. He explained that Eneloops are only charged to 75% capacity at the factory (as mentioned previously) and that the Eneloops supplied by TD are indeed authentic Sanyo Eneloops, but that the packaging on these particular Eneloops was done by a third party.

Thx for the help guys/gals!