when are Eneloops (etc) finally dead ?

I have some many-year-old eneloops and when I ''refresh-- recharge'' in my powerex they come up to ...1500 or lower .

Should I finally recycle these ?............. BUT bigger question ? ---- when are eneloops actually dead ?


(i have about 10 batteries that come back from the charger at 1400-1700)

If they do the job required then IMHO use them till they don't . Maybe move some to uses that are not too hard in demand, such as remotes etc....just thoughts. They will still be saving you money

ven said:

If they do the job required then IMHO use them till they don't.

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Sounds like a good rule of thumb.

GunnarGG said:

Sounds like a good rule of thumb.

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Not many may take them right down to use the full 2000mah potential, so to say loose 200-300 mah might not make actually that much difference with some uses.

I'm not sure if the powerex does just a single discharge/charge cycle or a continual loop of cycles checking each time for increase in capacity until there is little or none if it only does a single cycle try writing down the capacity of the batteries and trying a second or third cycle and see if they improve much as I have had some nimh batteries that do improve in capacity when cycled a few times that had not been used for a long period of time.

What charger are you using?

Try a break-in rather than a refresh/recharge. You might be able to squeeze a bit more out of them.

Guessing he's using a c9000?

Sorry for going off topic, but my two Sanyo eneloop pros had issues after I took them out of my Fenix LD41 which requires 4 cells. The other two in series were fine. Just these two that seem to show a battery level of less than 20%. have two quick chargers from Sanyo and they both refuse to charge these two.

newbie66 said:

Sorry for going off topic, but my two Sanyo eneloop pros had issues after I took them out of my Fenix LD41 which requires 4 cells. The other two in series were fine. Just these two that seem to show a battery level of less than 20%. have two quick chargers from Sanyo and they both refuse to charge these two.

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Are those chargers 2 cells/channel or single cell/channel chargers?

The "when" isn't easy to answer... I consider batteries "dead" if they only hold 0 volts and aren't able to be recharged anymore. This happened to me with a number of NiCd and non-LSD NiMh batteries, especially if not used for a longer time. There are two states that are reached before that though...

"Unusable" are batteries which aren't able to power any of my devices anymore, or only with very short runtime, either because they have incredibly high internal resistance, only a small fraction of capacity left or self-discharge within days.

"Don't pay off to keep" are batteries that would still work, but it doesn't pay off using them because they don't achieve full runtime anymore. This state is usually reached when they fall off to a certain percentage of the "standard" runtime (including self-discharge). That percentage for me would be between 40% and 75%... theoretically.

Actually, I'm doing an evaluation of my batteries when my usage pattern changes (i.e. if new devices needing batteries come in) or if the performance of some batteries degrades noticeably. At that point, the device using the most charges gets the batteries which would yield the highest runtime in it, the next device then gets those batteries of the ones left over that yield the best runtime in that device etc., down to the "lowest" device which is an 1AA wall clock. If the runtime any device would get is below 40% of the runtime that could be achieved with new batteries, the leftover batteries get discarded and replaced by new ones, and the sorting process starts anew. ;-) Actually, I'll also take care of putting batteries with similar capacities together. But that's almost too much to ask already because it all takes time to check and calculate, and it might well take more time than it's worth. Maybe it's best to just use the batteries until they drop dead and then replace them.

Lynx_Arc said:

Are those chargers 2 cells/channel or single cell/channel chargers?

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Umm, I use the Sanyo NC-MQR06W and Sanyo BC-MQR06.

These are the specs for Sanyo BC-MQR06:

• Input: 100-240V ~ 50-60 Hz 7W
• Output: 1V,2V, 1120mA × 2 (AA)
• Charge Control: Peak-Cut-Control
• Charging Time: 220 minutes (1-4 AA), 110 minutes (2 AA), 75 minutes (1 AA)
• Charge Indicator: 4 LEDs
• Size: 105 × 65 × 27 mm
• Weight: 111g

If the C9000 won't charge the cells anymore generally when they read HIGH in the charger i demote those batteries to other uses like my string lights that actually work pretty well with these high resistance cells. Eventually they will die off depending on how many cycles they have been through. Cycles can remain dormant in these high resistant cells but they won't output very well. I have these Duracell batteries that are still working but their capacity and internal resistance are bad. They function for many months, i got 2 in a digital clock that has been working for 6 months and still have half of their capacity! So these older 2005 Duracells are definitely cells that won't die. They need a refresh because i have noticed cells that barely work well but provide enough power for months in a clock do get worse over time and need to work more to retain a charge, because their capacity tends to fall off from non or low usage. Maybe those cells need to be retired.. but my criteria is when they no longer stay charged for a day or two when they are struggling to power a remote.

The main idea is you have to label these cells and often they are more time consuming than worth because you constantly have to keep these cells active for them to work well, but it pays off so you can keep your good stock of cells ready to go in an emergency. I'd probably just invest in some new Eneloops because they are worth every penny. You can also go for some Amazon Basics too for a little cheaper pricing.

Anyway with your situation i suggest doing a couple of break-ins if the cells can be charged in the C9000.

newbie66 said:

Sorry for going off topic, but my two Sanyo eneloop pros had issues after I took them out of my Fenix LD41 which requires 4 cells. The other two in series were fine. Just these two that seem to show a battery level of less than 20%. have two quick chargers from Sanyo and they both refuse to charge these two.

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They may have gone high resistant or maybe those cells are really dead. How old are these cells? You may need to check the manufacture date on the cell with a flashlight to see the date emboss. It should read it like 14 - 0400 (which is April 2014).

Would you throw away an alkaline and replace it after only 1/4th drain? Enough said...

Do a few discharge/recharge conditioning cycles then pair together sets of cells with similar remaining capacity for simultaneous use in each device. I mark the wrappers with a sharpie marker to distinguish them, but if I had enough cells to do then I'd use laser printer labels instead, partially because I already have them and partially because you can get a lot more info like the measurement and date on there.

MidnightDistortions said:

They may have gone high resistant or maybe those cells are really dead. How old are these cells? You may need to check the manufacture date on the cell with a flashlight to see the date emboss. It should read it like 14 - 0400 (which is April 2014).

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I was mistaken that only two of my cells are not functioning correctly, now all four have issues. Fenix LD41 messed up me cells? Kept them in there for maybe 2 month+. Never really used them a lot over the two years I had them.

Mine reads : 13 - 03YJ

I dont have any issues with mine so you may want to refresh or do a couple of break in with your cells to see if they improve.

Unfortunately I don't have any advanced NIMH chargers. Only the simple Sanyo chargers. May get the new Xtar SV2 rocket charger however.

newbie66 said:

Unfortunately I don't have any advanced NIMH chargers. Only the simple Sanyo chargers. May get the new Xtar SV2 rocket charger however.

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If nothing else you can play around with the cells to see if your current chargers will start putting charge in. Try forcing a little current into them from a 12V DC wall wart for a dozen or two seconds (hold rear of battery against outside (negative polarity) of adapter plug and a jumper wire from barrel plug center to positive battery terminal, or a paperclip), then see if the chargers like them more.

J_C said:

If nothing else you can play around with the cells to see if your current chargers will start putting charge in. Try forcing a little current into them from a 12V DC wall wart for a dozen or two seconds (hold rear of battery against outside (negative polarity) of adapter plug and a jumper wire from barrel plug center to positive battery terminal, or a paperclip), then see if the chargers like them more.

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Sorry, but the method you just gave is beyond my comprehension. I totally suck at such things.
I don't think I have the equipment you mentioned too.

One of my cells did managed to get charged by charger. However when I tested it using my Zebralight SC5 it could not power the highest mode.

The Fenix LD41 was lying next to my pillow actually so no rough treatment.

The method is as follows:

1. Grab a random AC/DC power adapter. 12V is a very common value for their output but anything from 5V to 20V would work so long as it's DC output, an AC/DC adapter not AC/AC, AC/DC being what almost any modern consumer electronics that have an adapter would use. They are often found powering laptops, tablets, networking equipment, and misc other things. It should be one with a barrel plug for easiest use. Here are some examples: https://www.google.com/search?q=electrical+barrel+plug&num=30&source=lnms&tbm=isch

2. Look for a symbol on it like the following, or use a multimeter to confirm that the outer jacket of the barrel connector is negative polarity:
http://i.stack.imgur.com/zsp7C.png The significance of the symbol is that the outer is negative and inner positive.

3. Grab a piece of electrical wire. Or a paperclip. Something conductive and at least 2.5" long.

4. Hold the rear, negative contact of the battery against the negative contact of the barrel plug. Oh, it helps to have the AC/DC adapter plugged into the wall.

5. Take the piece of wire or paperclip, whatever, and insert it in the center of the barrel connector, and the other end is touched against the top, positive terminal of the battery. This will force some current into the battery.

6. Try that for about 10 seconds. If the chargers still won't charge them, repeat the above but for 20 seconds or 30 seconds. If the battery starts getting hot, stop, let it cool down for a few minutes, then try charging it.

Another alternative is to put them in a dumb/trickle charger that just tries to force current in without any safety protection circuit, then after a few minutes, transfer them to your smarter chargers.