All my eneloop XX 2500 mAh batteries dropping like flies

gooseman

Newly Enlightened
Joined
Feb 24, 2009
Messages
72
In March 2014 I purchased a pack of 8 new eneloop XXs (4HR‐3UWX) from "large online retailer" (before Panasonic rebranding).

I have been using my Maha MH-C9000 to charge them at 1000ma for the past 16 months. I use all 8 batteries and then recharge them, so they are getting even wear.

Within the last week, my C9000 reported 'High' on 4 batteries. I estimate they have been charged only 60-70 times (they should handle 500 charges). The ones that are still "OK" are looking pretty tired in my flashlight fresh off the charger.

I tried C9000's "Refresh Analyze" - and as last resort "Break in", both to no avail (unit says "High" for failed batteries, ~1850-1900mAH for surviving ones).

Is it possible I charged them too quickly @1000mA? Thats less than 0.5C so I thought it would be OK. But the Panasonic BQ-CC17 charges at 300mA.

Thanks
 

Stefano

Flashlight Enthusiast
Joined
Sep 29, 2012
Messages
1,073
Location
Italy
In theory the Eneloop can be charged up to 2C (1C = battery capacity)
Example: The Eneloop white may be loaded up to 2000 mA.
The charger MQR06 (now no more in production) loads on a single AA battery to the speed of 1680 mA - 2 Eneloop AA at a speed of 1100 mA (inserted in "Quick" external slots)
I exclude that your charger has did any damage to your battery charging at 1000 mA
 

Mr Floppy

Flashlight Enthusiast
Joined
Feb 19, 2007
Messages
2,065
check out power me ups thread about cycle testing of these. You may get your answer to why the cycles are lower than expected.
 

MidnightDistortions

Flashlight Enthusiast
Joined
Aug 7, 2014
Messages
1,229
Location
Illinois, United States
What was the resting voltage when you regularly charge them? They most likely have high IR but you may want to refresh them with a different charger or try to fully discharge them in one of your lights. Try to get the resting voltage at 1.2 volts or at the very least discharge them to 0.9 volts in your light.
 

Kurt_Woloch

Enlightened
Joined
Nov 12, 2014
Messages
290
Are you completely draining the batteries each time or do you only partly discharge them? 500 cycles is the rating for around 60% depth of discharge at 0.2 C. If you discharge them completely every time the cycle life will probably be much lower... have been tested at around 150 cycles in this case. However, it puzzles me that you still only get half of that.
 

KeepingItLight

Flashlight Enthusiast
Joined
May 25, 2015
Messages
1,823
Location
California
Actually, was thinking of this thread
Eneloop XX Vs Turnigy 2400 Cycle Testing https://www.candlepowerforums.com/threads/391756


Fascinating read. I bookmarked it. Although I read a lot of it, I did not make it to the end.

What is the bottom line in the analysis made by Power Me Up? Does he say that internal resistance builds up faster in the Eneloop Pros in some circumstances compared to others?
 

Power Me Up

Enlightened
Joined
Mar 19, 2007
Messages
634
Location
Brisbane, Australia
In the testing that I've done - that others have already pointed to, I found that the cycle life of the Eneloop XX cells was nowhere near as good as the regular Eneloop cells. The results that I've obtained are only directly applicable to the testing method that I used, but I would be surprised if you could find a usage scenario under which the Eneloop XX cells performed anywhere nearly as well as regular Eneloops when it comes to cycle life.

I don't think that charging them at 1000 mA on the C9000 would likely cause a (significant) reduction in cycle life - the 100 mA top off for 2 hours might cause a little degradation, but I think that if the cells were being deeply discharged, that's much more likely to be the cause of them developing high internal resistance so quickly.
 

WalkIntoTheLight

Flashlight Enthusiast
Joined
Jun 18, 2014
Messages
3,967
Location
Canada
I think that if the cells were being deeply discharged, that's much more likely to be the cause of them developing high internal resistance so quickly.

What do you consider deeply discharged? IIRC, you do your discharge tests down to 0.9v. I'm assuming you don't consider that a deep discharge? Or do you? Most of my flashlights cut out at around 0.8v or 0.9v per cell, so do you think that is causing damage to standard Eneloops? (I haven't noticed any, but I don't have a thousand cycles on them either.)

I may be misremembering some of your posts, but I thought you busted the conventional thinking that a full discharge was bad?

I know that discharging so low in a multi-cell circuit that you cause reverse-charging is definitely bad. Is that what you mean about deep-discharging causing high IR?
 

TinderBox (UK)

Flashlight Enthusiast
Joined
Jan 14, 2006
Messages
3,488
Location
England, United Kingdom
Is this not the C9000 being too fussy, and if the OP did not have one, he would have most likely not have had a problem with them, Has he had any reduction in runtime, or noticed any unusual self-discharge issues.

I would give Panasonic or Maha an email and see what they say about the HIGH reading on cells with less than 100 cycles.

John.
 

WalkIntoTheLight

Flashlight Enthusiast
Joined
Jun 18, 2014
Messages
3,967
Location
Canada
Is this not the C9000 being too fussy, and if the OP did not have one, he would have most likely not have had a problem with them, Has he had any reduction in runtime, or noticed any unusual self-discharge issues.

He did say that on the ones he can still charge, they only have about 1850-1900mAh on them. So, they've lost over 25% capacity. However, we don't know what discharge rate he used for testing. If they're developing high IR, then a fast discharge will definitely show a huge drop in capacity.

Whatever the case, unless his C9000 is malfunctioning, the batteries definitely look like they're slowly failing.
 

ChrisGarrett

Flashlight Enthusiast
Joined
Feb 2, 2012
Messages
5,725
Location
Miami, Florida
As I've stated before, I bought 8 Sanyo 2700s in 2/12 and all eight of them have >2.00v IR on my Maha. Four of them are up above 2.60v, so they're about to be retired, since it's getting to be a pain coaxing them into CHARGE. With the one quad, I can insert/charge/remove them a half dozen times and bring the IR down to 2.10v and get them to cycle.

If I have 100 cycles on them in my Marantz RC5000/Pronto remote and wireless RF keyboard, I'd be surprised.

I've always charged them up at 1A.

Now, I just ran a Refresh/Analyze on my 8 Duracell Ion Core 2400 Duraloops and after about 18-20 months of very minor use, they tested in as a group at an average of 2360mAh with an extreme spread of 45mAh, so pretty close.

Those 8, out of their packs averaged 2470mAh with an ES of 70mAh, so a loss of ~4.5%. IRs on the refresh/analyze cycle were ~1.50v, so they're in pretty good shape after ~20 months.

I also bought 12 Duraloop 2000mAh Gen.2 AAs in August of 2013 and 8 of the 12 that I have sound measurements on, averaged 1973mAh with an ES of 43mAh. After ~23 months, those 12 batteries measured an average of 1872mAh with an ES of 55. The 8 that I accurately measured when new, averaged 1877mAh with an ES of 45mAh.

That's an average loss of 4.9% after almost 2 full years of mostly sitting unused. IRs are in the 1.55v range, so they're holding up.

Chris
 

swan

Banned
Joined
Apr 21, 2011
Messages
669
Location
sydney aus
I bought 16 x aa eneloops and 4 pack of xx back in 2013, about a year ago i noticed the xx,s would struggle to run my nitecore ea4 in turbo, with the ui switch flashing[50% battery] in protest hot off the charger. The normal eneloops are still like new and wont invoke a ui battery indication flash until 5.2volts.
About a month ago they would only go up to medium level on the ea4 and now finally they wont charge at all.
So for me even though it is only one set of xx,s [12 x charges max] i have sampled, i think i will stay with the normal eneloop 2000mah japanese made cell.
It s funny i guess, i am going to bin them but its kinda hard to admit they are done.
 

MidnightDistortions

Flashlight Enthusiast
Joined
Aug 7, 2014
Messages
1,229
Location
Illinois, United States
What are the manufacture dates on these cells? Seems odd the Eneloop XX's are only lasting 2-3 years when Duraloops are guaranteed to last 5 years. Are these the ones from Sanyo or Panasonic?
 

swan

Banned
Joined
Apr 21, 2011
Messages
669
Location
sydney aus
What are the manufacture dates on these cells? Seems odd the Eneloop XX's are only lasting 2-3 years when Duraloops are guaranteed to last 5 years. Are these the ones from Sanyo or Panasonic?
My ones are Sanyo HR3UWXA min 2400 mah- date code 12-02A T. My wrappers started to peel along the seem also. As i wrote before, these would of had 12 charges max [prob less] and charged with the same charger as my normal eneloops [prob 30+ recharges] which all look and perform as new. Any one else have XX,s crap out?
 

Power Me Up

Enlightened
Joined
Mar 19, 2007
Messages
634
Location
Brisbane, Australia
What do you consider deeply discharged? IIRC, you do your discharge tests down to 0.9v. I'm assuming you don't consider that a deep discharge? Or do you? Most of my flashlights cut out at around 0.8v or 0.9v per cell, so do you think that is causing damage to standard Eneloops? (I haven't noticed any, but I don't have a thousand cycles on them either.)

I may be misremembering some of your posts, but I thought you busted the conventional thinking that a full discharge was bad?

I know that discharging so low in a multi-cell circuit that you cause reverse-charging is definitely bad. Is that what you mean about deep-discharging causing high IR?

I'd consider going below 0.9V to be a deep discharge. Having said that, in other testing that I've been doing, the results are indicating that even regularly discharging down to only 0.9V does cumulative damage to the cells - even for regular Eneloops. I've got a pair of Eneloops that I've been discharging down to only 1.1V and they've done a lot more cycles than in any other test that I've run:

http://www.ultrasmartcharger.com/phpBB3/viewtopic.php?f=5&t=91

My recommendation these days is that if you want your cells to last, you should charge them early - before they go completely flat - as long as your charger isn't damaging the cells by overcharging them.
 

WalkIntoTheLight

Flashlight Enthusiast
Joined
Jun 18, 2014
Messages
3,967
Location
Canada
I'd consider going below 0.9V to be a deep discharge. Having said that, in other testing that I've been doing, the results are indicating that even regularly discharging down to only 0.9V does cumulative damage to the cells - even for regular Eneloops. I've got a pair of Eneloops that I've been discharging down to only 1.1V and they've done a lot more cycles than in any other test that I've run:

http://www.ultrasmartcharger.com/phpBB3/viewtopic.php?f=5&t=91

My recommendation these days is that if you want your cells to last, you should charge them early - before they go completely flat - as long as your charger isn't damaging the cells by overcharging them.

Thanks, yeah, that does look like 1.1v discharging is far easier on the cells than the 0.9v discharging you did in your other Eneloop test.
 
Top