# NiMH leakage. Does it happen?



## Canuke (Nov 19, 2007)

After having about 8 out of 40 "Ultralast" AA's come up leaky despite having been little used, I tossed all of them thinking that it was due to their being a cheap brand. I went through everything I could think of that might still have these cells in them.

Just yesterday I found a Duracell AA sitting on my bench, all smelly with battery guts. That one was about half discharged, I'd guess.

All this was making me look forward to eventually using Eneloops in all my infrequent-use devices -- until I realized that I was simply assuming that they wouldn't leak either.

Has anyone ever seen a NiMH leak under normal conditions? Abnormal conditions? How about LSD NiMH (Enelopp, Hyrbid/Hybrio etc.)?


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## Fallingwater (Nov 19, 2007)

Eneloop cells do not contain liquid electrolyte, therefore they cannot leak.


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## Canuke (Nov 19, 2007)

Ah, I saw that thread but didn't make the connection -- interesting!

So, I guess that makes Eneloops and/or LSD NiMH's in general, just flat-out the best option for use in devices where you'd like to insert and forget them over a long period -- but still have them work a year later. I've been pondering this option since the spate of leaky alkalines I've had lately. The only drawback I can see is cost.


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## Fallingwater (Nov 19, 2007)

The best cell for the use you describe is probably a primary lithium, but yeah, LSD NiMH cells are a close second.


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## KevinL (Nov 19, 2007)

What about traditional NiMH - I thought they didn't use liquid either? (or was I mistaken..)

I've had traditional (non-LSD) NiMH leak before.


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## ProofTech (Nov 19, 2007)

KevinL said:


> I've had traditional (non-LSD) NiMH leak before.


 Was the liquid highly corrosive like the liquid from an alkaline battery is?


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## NA8 (Nov 22, 2007)

How about the C & D size Nimh ? 

http://thomasdistributing.com/shop/...41_403.html?osCsid=1fnkk62up8bv7933es5o0iobt7

Sounds like a solution to leaky cells in Maglites. Expensive though, you could just replace the Maglite


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## Curious_character (Nov 22, 2007)

I've sometimes seen furry white stuff which came from the cell. I recall reading at manufacturers' web sites that this could result from leaving the cell connected to a very low current drain load which completely discharges the cell. This could happen in flashlights where the on/off function is controlled by circuitry instead of a mechanical connection of the main current path, if you left the battery in the light for a long time.

c_c


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## half-watt (Nov 22, 2007)

i've had corrosion form a number of times on the terminals (either pos. or neg., in my experience) of some cheaper NiMh AAA and AA cells.


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## jama12uk (Jan 21, 2010)

*Do Sanyo Eneloops leak?*

Has anyone ever had sanyo eneloops (AA) leak in their flashlights?


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## DoctaDink (Jan 21, 2010)

*Re: Do Sanyo Eneloops leak?*

Nope, not yet.


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## RtOaNn (Jan 21, 2010)

*Re: Do Sanyo Eneloops leak?*

nope, haven't had any that leaked.


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## Locoboy5150 (Jan 21, 2010)

*Re: Do Sanyo Eneloops leak?*

No Eneloop or Duraloop leaks over here.


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## strinq (Jan 21, 2010)

*Re: Do Sanyo Eneloops leak?*

Actually it should be "Can Eneloops leak?"


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## netprince (Jan 21, 2010)

*Re: Do Sanyo Eneloops leak?*

Yes, they can leak/vent, and it has happened to someone I know. We believe it was due to over discharge.


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## strinq (Jan 21, 2010)

*Re: Do Sanyo Eneloops leak?*



netprince said:


> Yes, they can leak/vent, and it has happened to someone I know. We believe it was due to over discharge.



So they're not leak proof too. Hmmm...but I'm guessing those instances are way less than with alkalines.


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## Saint_Dogbert (Jan 21, 2010)

*Re: Do Sanyo Eneloops leak?*

It can probably happen, but given that Ni-MH don't have a bunch of nasty paste in them, it's probably not that likely. Venting is more likely, and not terribly serious as it is unlikely to be explosive, as with Lithiums or Li-ion.


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## MarNav1 (Jan 21, 2010)

*Re: Do Sanyo Eneloops leak?*

Not so far................Excellent cells IMO.


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## Mr_Light (Jan 21, 2010)

*Re: Do Sanyo Eneloops leak?*

I have used over a hundred NiMH cells (at least a dozen brands) over the years and never had a leak. I have left traditional NiMH cells in remotes and other things for years at a time without leaks.


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## Mr Happy (Jan 21, 2010)

*Re: Do Sanyo Eneloops leak?*

Like all NiMH cells they will vent gases if you reverse polarize them by over discharge in a multi-cell device. They will also vent gases if you seriously overcharge them at a high rate.

But in normal use they are sealed and will not leak unless you drill a hole in them.


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## TONY M (Jan 21, 2010)

*Re: Do Sanyo Eneloops leak?*

No problems from me personally in any Eneloops or their re-badged twins.


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## Nyctophiliac (Jan 21, 2010)

*Re: Do Sanyo Eneloops leak?*

I've been using NiMh's for years and years, and eneloops for about two years? I must have had a couple of hundred Batteries in all - the ones I got rid of were because they were exhausted - wouldn't hold a charge - or the wrapping was too badly damaged and I was in danger of shorting out a cell. 

But not one NiMh cell has leaked in any appliance or out of it.

I've had many many alkalines of all brands that have leaked. Procell included ( In a 5 AA portable TV - switch on POP! White goo all over my battery compartment. TV never quite the same since! )

Eneloops are lovely, but get a good intelligent charger, not a cheapy fast overcharger!


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## Conan (Jan 21, 2010)

*Re: Do Sanyo Eneloops leak?*



strinq said:


> So they're not leak proof too. Hmmm...but I'm guessing those instances are way less than with alkalines.



I think the only instances where they leaked (as reported in CPF) was while they were charging (overcharge) not while in use.


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## Eugene (Jan 21, 2010)

*Re: Do Sanyo Eneloops leak?*

I've had two NiMH leaks now, not eneloops, but onne of the Titainium 2100lsd that battery junction cleared out a year ago and one radio shack so I can attribute them to being crap cells.


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## ICUDoc (Jan 21, 2010)

*Re: Do Sanyo Eneloops leak?*

I've 36 eneloops on various rotations (high and low drain). No leaks.


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## Samuraidog (Jan 30, 2010)

*Re: Do Sanyo Eneloops leak?*

I just did a google search for "eneloops leak" and found this thread.

I had 4 AA eneloops in two D adapters inside a 2 cell Maglite LED. The flashlight is only about 2 months old, as are the eneloops. I went to use it the other day and it no longer worked. I unscrewed the end of the flashlight and noticed that it seemed wet inside. 

To my surprise, these eneloops (all 4 AAs) had leaked and the white cap was melted away (white covering partially melted too). 

My question is...How dangerous are these batteries? I assume there is acid in them. I washed my hands really good after I took the batteries out. Also, I am wondering if I should just throw the flashlight away. 

I'll try to attach photos, but I am new to this site, so apologies if my photo does not show up.


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## Mr Happy (Jan 30, 2010)

*Re: Do Sanyo Eneloops leak?*

Oh dear...

There's no serious danger from the chemicals. If you washed your hands afterwards you will be fine.

Eneloops really don't do that kind of thing by themselves. My best guess is that a short circuit somehow developed causing the batteries to overheat and spill their guts. The problem might be with the light or with the two D adapters. 

Was the light working before you put it away? Could anyone else have got to the light while it was stored? For instance a certain way this could happen is if the eneloops were put in the D adapters one-up, one-down. This would cause a direct short circuit and would result in the melt-down pictured. Do you have children in the house? Pixies?


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## Samuraidog (Jan 30, 2010)

*Re: Do Sanyo Eneloops leak?*

Yes. The light was working before I put it away. I am sure I turned the light off before putting it away last.

I have no kids, so that is out of the question. I asked my wife if she used it, but she swears she never even touched the flashlight. We are the only two in the house. 

I had the batteries in exactly as is shown in the image attached, so I assume the batteries were inserted correctly. And the filled adapters were inserted into the light just as I would regular D size batteries.

I also have a 3 cell (D cell) Maglite LED and I have the eneloops and same adapters in exactly the same configuration as the 2 cell light. I have no problems with the 3 cell Maglite. 

I will be embarrassed if I somehow screwed up the alignment of these batteries, but I used them just like the photo below. What I have I done incorrectly?

Should I see if I can claim a warranty on these batteries (if it is even worth sending them back), or am I responsible because I did something wrong?

Thanks.
http://i695.photobucket.com/albums/...1dec2009/aa-to-d-adapter-incorrect-config.jpg


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## Russel (Jan 31, 2010)

*Re: Do Sanyo Eneloops leak?*

Never had any of my (few dozen AA and a few AAA sized) Eneloops leak. I have had several alkaline batteries leak...I no longer use alkalines.


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## Magic Matt (Jan 31, 2010)

*Re: Do Sanyo Eneloops leak?*



Samuraidog said:


>



:shakehead

Either that's not an AA to D cell adapter, or that picture has the cells shown in the wrong way.

A standard AA to D cell adapter has all cells pointing the same direction. The only difference would be if it's an AA to D size adapter designed to provide a higher voltage instead of greater capacity (useful, but more specialised) in which case that would be right, and it would give out 3V not 1.5V with alkaline cells... that would not really be suitable for an unmodified Maglite though to my knowledge.


*Edit:
*Found the page
http://www.suntekstore.com/aa-to-d-size-battery-adapter-white-case.html

That picture is wrong, and would most certainly cause the problem you had with the cells. They are short circuiting as soon as you close the bottom if you put them in as showin in the picture.


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## Mr Happy (Jan 31, 2010)

*Re: Do Sanyo Eneloops leak?*



Samuraidog said:


> I had the batteries in exactly as is shown in the image attached, so I assume the batteries were inserted correctly. And the filled adapters were inserted into the light just as I would regular D size batteries.


Oh my, no, no no! 

As Magic Matt said, that picture shows the batteries inserted incorrectly. The metal plate at the top will connect + to −, and the similar plate at the bottom will connect − to +. The result will be a direct short circuit of the batteries and they will quickly destroy themselves.

The correct way to insert the batteries is with both button ends pointing upwards, just like the D cell the adapter is replacing.



> I also have a 3 cell (D cell) Maglite LED and I have the eneloops and same adapters in exactly the same configuration as the 2 cell light. I have no problems with the 3 cell Maglite.


Take the batteries out immediately, if it is not already too late, or the same thing will happen to them.

I can only assume the light works when tested because of poor contact between the cells and the adapter somehow.



> I will be embarrassed if I somehow screwed up the alignment of these batteries, but I used them just like the photo below. What I have I done incorrectly?
> 
> Should I see if I can claim a warranty on these batteries (if it is even worth sending them back), or am I responsible because I did something wrong?


Sadly, the damage was caused by your misadventure. That picture is utterly wrong and really ought not to be shown on the web site like that.


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## UserName (Jan 31, 2010)

*Re: Do Sanyo Eneloops leak?*



Samuraidog said:


>



:shakeheadDead cells walking!!:shakehead

:mecry:RIP.:mecry:


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## Samuraidog (Jan 31, 2010)

*Re: Do Sanyo Eneloops leak?*

Thanks to all for the replies. I'm kind of embarrassed because I feel like I should have known better. 

Here is the story.

I bought these adapters on ebay. When I got them, there were NO INSTRUCTIONS and there are no indicators on the adapter casing itself showing polarity. (Actually, there is a single AA battery image with an arrow pointing to a D battery image molded into the casing, but it is sideways on the casing and it doesn't clearly indicate insertion polarity. At least it doesn't to me.)

When I first got these adapters, I used the 2 cell Maglite to test the adapters/batteries. Not having any instructions, common sense told me to put the + pole of both batteries facing upward (as you have instructed). When I did that, the flashlight DID NOT WORK. I couldn't figure out why. 

I then went back to the ebay site to see if there were any kind of instructions/photos that could show what I was doing wrong. I then came across the posted photo. It was the only photo I could find with these adapters that actually clearly showed polarity in the adapters. 

It didn't look right, but I figured I'd give it a shot. I did exactly as the photo showed and the flashlight then worked! It was a head-scratcher moment, but thinking I now had it right, I filled the 3 cell Maglite with that same configuration. The 3 cell worked fine too.

I usually take pride in thinking I know what I am doing, but this makes me really look like an idiot. 

Thanks for your help. I have just "fixed" the configuration on the 3 cell Maglite. Luckily, there was no leakage on those batteries. I don't know what kind of damage it has caused, but I'm hoping I can get some life out of them. 

It was an expensive lesson losing 4 eneloops, but it could have been worse.

Thanks again. 



Mr Happy said:


> Oh my, no, no no!
> 
> As Magic Matt said, that picture shows the batteries inserted incorrectly. The metal plate at the top will connect + to −, and the similar plate at the bottom will connect − to +. The result will be a direct short circuit of the batteries and they will quickly destroy themselves.
> 
> ...


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## Samuraidog (Jan 31, 2010)

*Re: Do Sanyo Eneloops leak?*

Like comedian Bill Engvall says, "Here's your sign".

Thanks guys for not being too harsh on me for the numbskull move.


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## Mr Happy (Jan 31, 2010)

*Re: Do Sanyo Eneloops leak?*

The remaining puzzle is the case of the work/didn't work observations. Perhaps it is because the adapter is poorly constructed and does not make good contact with the AA cells inside it? I think you should check that there is good firm contact with both cells at both + and − ends when the adapter is closed.

Also it sometimes happens that these adapters do not make good contact with the springs inside the light. Real D cells usually have much larger contact areas than the plastic adapters have.


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## Lightcrazycanuck (Jan 31, 2010)

*Re: Do Sanyo Eneloops leak?*



Samuraidog said:


> I just did a google search for "eneloops leak" and found this thread.
> 
> I had 4 AA eneloops in two D adapters inside a 2 cell Maglite LED. The flashlight is only about 2 months old, as are the eneloops. I went to use it the other day and it no longer worked. I unscrewed the end of the flashlight and noticed that it seemed wet inside.
> 
> ...


 

:mecry:RIP :mecry:


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## Bright+ (Feb 1, 2010)

*Re: Do Sanyo Eneloops leak?*



Samuraidog said:


> I just did a google search for "eneloops leak" and found this thread.
> 
> I had 4 AA eneloops in two D adapters inside a 2 cell Maglite LED. The flashlight is only about 2 months old, as are the eneloops. I went to use it the other day and it no longer worked. I unscrewed the end of the flashlight and noticed that it seemed wet inside.
> 
> ...



Were the melted cells on the tail end? If the covering on one of the top-end chaffed or punctured and any one of the front-end batteries touched the body, it would dead short the bottom set. 

Individual cell rechargeable batteries are the most vulnerable type to this.

They're subject to abrasion from insertion each and every time they're removed for charging and loading. 

They're subject to far more insertion cycles than alkaline, so the wrapping sees more wear and tear.

In your type of casing this seems unlikely, but something definitely crow-bar shorted. The electrolyte is sodium and or potassium hydroxide. The covering is PETE, PP or PE that's resistant to caustics. The cells got hot enough to melt the wrapper and pressurized enough to vent the electrolyte. 

So, the cells somehow shorted internally or the load shorted. Seeing all four cells were affected, I think its an external short.


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## Magic Matt (Feb 1, 2010)

*Re: Do Sanyo Eneloops leak?*



Bright+ said:


> So, the cells somehow shorted internally or the load shorted. Seeing all four cells were affected, I think its an external short.



Sorry, but you're mistaken. Please read the answers to the OP - the reason the batteries shorted has already been answered.


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## Mr Happy (Feb 1, 2010)

*Re: Do Sanyo Eneloops leak?*



Magic Matt said:


> *Edit:
> *Found the page
> http://www.suntekstore.com/aa-to-d-s...hite-case.html


When looking at the other pictures on that page, note how small the positive button is on the outside of the adapter. It is tiny, with most of the top surface being non-conductive plastic. This is a very poor design that is common with such adapters, and means that the spring in the end of many flashlights will not make a connection with the battery and the light will fail to work. (Compare with a real alkaline D cell where the whole top surface is a metal plate. But then again, many real NiMH D cells have a similar but not-quite-so-small positive button.)


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## Bright+ (Feb 1, 2010)

*Re: Do Sanyo Eneloops leak?*



Mr Happy said:


> When looking at the other pictures on that page, note how small the positive button is on the outside of the adapter. It is tiny, with most of the top surface being non-conductive plastic. This is a very poor design that is common with such adapters, and means that the spring in the end of many flashlights will not make a connection with the battery and the light will fail to work. (Compare with a real alkaline D cell where the whole top surface is a metal plate. But then again, many real NiMH D cells have a similar but not-quite-so-small positive button.)




For that very reason, the Task Force 2C does not work with eneloop C adapter, because the positive contact makes use of the metal disc around the button.


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## Bones (Feb 4, 2010)

*Re: Do Sanyo Eneloops leak?*



> ----- Original Message -----
> From: [email protected]
> Sent: Tuesday, February 02, 2010 2:16 AM
> Subject: Re: Suntek Store Website - Incorrect Image
> ...



Kudos to SunTekStore for their prompt followup:





An unintended consequence though:

The original image depicting the incorrect configuration was hot-linked, which means it now shows the correct configuration even though the accompanying posts state otherwise.

It would therefore be appreciated if the authors (or a moderator) could notate those posts accordingly.


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## Bones (Feb 4, 2010)

*Re: Do Sanyo Eneloops leak?*

Further to the above post, here's a copy of the original SunTekStore image with the incorrect cell configuration which can be substituted for the hot-linked image which now shows the correct configuration:







Image URL:


```
http://i695.photobucket.com/albums/vv314/ptc2oo9/028fld31dec2009/aa-to-d-adapter-incorrect-config.jpg
```


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## Samuraidog (Feb 4, 2010)

*Re: Do Sanyo Eneloops leak?*

Thanks. I edited my post to reflect the updated link.



Bones said:


> Further to the above post, here's a copy of the original SunTekStore image with the incorrect cell configuration which can be substituted for the hot-linked image which now shows the correct configuration:
> 
> 
> 
> ...


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## Samuraidog (Feb 9, 2010)

*Re: Do Sanyo Eneloops leak?*

Interestingly, they still haven't fixed the thumbnail version of the pic and I still see it all over ebay. Once you click on the thumb, you get the revised pic.

http://images.channeladvisor.com/Sell/SSProfiles/60000383/Thumbs/114/tn3_8480700.jpg




Bones said:


> Further to the above post, here's a copy of the original SunTekStore image with the incorrect cell configuration which can be substituted for the hot-linked image which now shows the correct configuration:
> 
> 
> 
> ...


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## Bones (Feb 9, 2010)

*Re: Do Sanyo Eneloops leak?*



Samuraidog said:


> Interestingly, they still haven't fixed the thumbnail version of the pic and I still see it all over ebay. Once you click on the thumb, you get the revised pic.
> 
> http://images.channeladvisor.com ... 8480700.jpg



Where are finding that thumbnail Samuraidog? I only see a thumbnail of the revised image on the SunTekStore 2-AA to D adapter page:

http://i.suntekstore.com ... 10006053_3_inset.jpg

As well, I only see the thumbnail of the revised image on their eBay listings for the adapter, ie:

http://cgi.ebay.com ... item=380203626354
.


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## Samuraidog (Feb 18, 2010)

*Re: Do Sanyo Eneloops leak?*

Apologies for not writing earlier. I haven't checked this page in a few days.

I see it all over ebay doing a search for "aa to d battery adapters". Look specifically at the listings with the thumbnail that has the orange starburst in the upper left corner.

Here is an example.

http://cgi.ebay.com/4-X-Adapter-Cel...emQQptZLH_DefaultDomain_0?hash=item4a9e713da6



Bones said:


> Where are finding that thumbnail Samuraidog? I only see a thumbnail of the revised image on the SunTekStore 2-AA to D adapter page:
> 
> http://i.suntekstore.com ... 10006053_3_inset.jpg
> 
> ...


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## Kramer. (Feb 19, 2010)

*Re: Do Sanyo Eneloops leak?*

Have been using Enloops for quite a while & never had any leak. I even found some recently that had been sitting in an unused remote control for over a year & they were fine. Recharged OK too


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## cancow (Sep 6, 2012)

*Can eneloops leak?*

I know Regular aa batteries leaks often, but which ones do not? Can cr123's leak?


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## AnAppleSnail (Sep 6, 2012)

*Re: Can eneloops leak?*

Eneloops and CR123s only leak when abused horribly. In single-cell applications they are far less likely to leak during use than in multicell applications. Neither chemistry will spontaneously leak if used carefully. There is no such guarantee for alkaleaks. All alkaline primaries can leak, regardless of age, condition, or state of charge. You can get better mileage getting alkaleaks at hobby stores, which take better care of them in the package. Those will also leak sometime.

In short: You have to run Eneloops down past dead so that a weak cell is reverse-charged. It may then leak, but not very much. A CR123 when badly matched to a weak cell will occasionally make the weak cell vent horribly toxic fumes. This is a rare thing, but generally if your light suddenly hisses, you should get yourself and everything that breathes out of the room. Then research the dangers therein before returning.


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## zulutime1 (Mar 30, 2013)

*Leaking Eneloop AA cell*

Until now, thanks in part to reading CPF when I researched battery options, I thought NiMH batteries never leaked. I've created an account on this forum to share my shocking story with you. I just had an Eneloop AA leak in a very expensive ($1500) piece of electronics and I am completely freaked out. I have never had any prior problems with NiMHs leaking.

Background:


I bought a 4 pack of AA Eneloops online directly from B&H Photo Video sometime around 2 years ago. The battery model is HR-3UTGA, min. 1900 mAh. 
Since purchase, this particular cell has undergone only two, at most three, cycles. Charging has always been with an older Energizer NiMH charger (model CHDCWB-4) which has worked well with all my NiMH batteries. 
The cell was in a Polimaster PM1703M which is a portable scintillation counter. It takes a single AA cell. This is a very low load. Current draw when "off" (it's never totally off) is in the low microamps and when on is probably just a few milliamps. 
95% of the time the scintillation counter is off - I often turn it on just for a few hours every few weeks. 

Prior to today, the counter was "off" for probably a month. I turned it on this morning, and saw the display indicated a low battery level. I made a mental note to change the battery after use today (I have two Eneloops - I swap them out and recharge the other). Four hours later, I looked at it and noticed the display was off. I went to change the battery; it is in a waterproof battery compartment protected by a threaded screw-in metal plug with o-ring (the negative battery terminal is a spring inside the plug). I saw a white crust all around the outside edge of the unit. This is what the battery plug looks like generally (found this photo online, I didn't take any photos of mine):

http://u.jimdo.com/www56/o/s54e4adbc23c5c6d0/img/i37b34487f2c7a5de/1321792267/orig/image.jpg

You stick a quarter in the X shaped groove and turn to unscrew the plug. Well it wouldn't open and I had to eventually put the quarter in a vise and then use both hands to instead rotate the unit itself to get the plug loosened. The threads of the plug, o-ring, spring terminal in the plug, everything was covered in white crusty stuff. Fortunately only the negative side of the cell leaked (which is the end contacting the plug) so I was able to clean it up with some water, q-tips, and paper towels without having to try to disassemble the unit. I didn't take any photos of the crusty stuff on the unit because I was so freaked out that I wanted to get it cleaned up as fast as possible.

I did take several photos of the battery however:

http://imgur.com/a/THBqU

Despite the amount of white crusty battery stuff on the plug and the terminal and around the outside of the plug, there doesn't seem to be much on the battery itself - but you can see where it's coming from and also the skin of the battery looks wet in places as if there's liquid trapped somewhere below the very outer layer. This battery has never been dropped, scratched, or anything.

As I write this, I have the unit drying out (since I used water in part of the battery compartment to clean it) and will let it dry out overnight before I put another cell in and check if it still works. Likely since it was pretty contained all should be well, but my heart definitely skipped beats when this happened.

I'm not sure what to think. The cell was probably fairly discharged when this happened but that shouldn't cause this. I purposely switched from alkalines to NiMH because of leakage, and I chose Eneloops because I thought they were the best. I think I'll switch to Energizer lithiums now.

I hope you all find this is as eye-opening as I have.


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## oKtosiTe (Mar 31, 2013)

*Re: Leaking Eneloop AA cell*

Whether this has anything to do with your issue is impossible to say, but that charger charges at a rate lower than recommended for Eneloops. Eneloops are supposed to be charged at 1A, whereas that charger presumably charges at around 0.3A and might therefore not terminate properly.


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## thedoc007 (Mar 31, 2013)

*Re: Leaking Eneloop AA cell*

Well, I'm not shocked at all. Leaks may be much less frequent, but with the millions and millions of Eneloops that have been made, I have no doubt whatsoever that a few will be defective. Just chalk it up to bad luck (and be grateful it wasn't worse), and keep using them. There is no battery type or brand that is perfect.


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## uk_caver (Mar 31, 2013)

*Re: Leaking Eneloop AA cell*



oKtosiTe said:


> Whether this has anything to do with your issue is impossible to say, but that charger charges at a rate lower than recommended for Eneloops. Eneloops are supposed to be charged at 1A, whereas that charger presumably charges at around 0.3A and might therefore not terminate properly.


The datasheets for the HR-3UTG, HR-3UTGA, and HR-3UTGB actually refer throughout to a 2A/1C charge rate, but don't say it's the only acceptable rate.
360mA/~0.2C would be low for a smart charge rate, at least for a charger not well designed to terminate at low rates.

However, that's pretty moot since, according to the datasheet:
http://datasheet.octopart.com/CHDCWB-4-Energizer-datasheet-34010.pdf


> The charger is designed to charge "AA" NiMH 2500mAh batteries and "AAA" NiMH 850mAh batteries in 8.5 hours. For lower rated capacity batteries, simply remove the batteries before the charge cycle completes based on the following charge times. Higher capacity batteries will require additional time.
> [table of capacities and times follows]


So it's a timed dumb charger, and hence probably the lower the charge rate the better - for a given total amount of overcharge, the slower it happens, the more the cell is likely to be able to cope with it.

As for the OP's


> I thought NiMH batteries never leaked


I couldn't help noticing the '_If leaked liquid gets in the eyes..._' warning on the photos of the leaked cell.
Leakage is rare, but not impossible, and using a dumb charger is meaningfully increasing the risks of leakage..

I'd also tend to take the view that in a battery-powered piece of professional kit costing $1500, _it_ should really be designed so that battery leakage was unlikely to cause damage, and/or have prominent warnings not to store it with cells inside.


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## zulutime1 (Mar 31, 2013)

*Re: Leaking Eneloop AA cell*



uk_caver said:


> Leakage is rare, but not impossible, and using a dumb charger is meaningfully increasing the risks of leakage..



I didn't even realize I was using a dumb charger. Now I'm going to get something better. Thanks for pointing this out!


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## Mr Happy (Mar 31, 2013)

*Re: Leaking Eneloop AA cell*

This seems really strange. Eneloops like other NiMH batteries are completely enclosed in a steel case like a bottle that extends all the way round the negative end without any gaps. The case is crimped to seal it at the positive end and is designed to withstand considerable internal pressure. The case is chemically inert to the internal electrolyte and will not corrode from the inside out under normal conditions.

You have not shown any pictures of the ends of the cell, only the sides where there is nothing much to see. Can you also show the ends?

My guess is that the cell may have been damaged in some way. Is it possible that the battery plug or spring could exert lots of pressure on the cell, or that maybe the spring has a sharp point on it that can puncture the casing?


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## Mr Happy (Mar 31, 2013)

*Re: Leaking Eneloop AA cell*



zulutime1 said:


> Until now, thanks in part to reading CPF when I researched battery options, I thought NiMH batteries never leaked.


This is basically true. If you leave an NiMH battery sitting by itself for years it will not leak. The casing is made of inert materials and the internal electrodes and electrolyte do not decompose in a way that might produce any gas that could burst the cell.



> I think I'll switch to Energizer lithiums now.


As with NiMH batteries, these do not leak in normal situations. However all batteries can leak if punctured or subjected to external trauma. The difference is that lithium batteries may catch fire if this happens, which would cause more damage than leaking electrolyte from an NiMH cell.


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## zulutime1 (Mar 31, 2013)

*Re: Leaking Eneloop AA cell*



Mr Happy said:


> This seems really strange. Eneloops like other NiMH batteries are completely enclosed in a steel case like a bottle that extends all the way round the negative end without any gaps. The case is crimped to seal it at the positive end and is designed to withstand considerable internal pressure. The case is chemically inert to the internal electrolyte and will not corrode from the inside out under normal conditions.
> 
> You have not shown any pictures of the ends of the cell, only the sides where there is nothing much to see. Can you also show the ends?
> 
> My guess is that the cell may have been damaged in some way. Is it possible that the battery plug or spring could exert lots of pressure on the cell, or that maybe the spring has a sharp point on it that can puncture the casing?



Here are photos of the ends:

http://imgur.com/a/Dg7zz

The spring definitely doesn't have a sharp point (it's a very smooth spring, unlike what you find in RadioShack battery holders, for example). I believe the spring may exert slightly more pressure than the average battery holder but nothing extreme. I have the other Eneloop cell which was previously in the unit and there's no marks on its negative terminal that would tend to indicate spring-caused damage.



Mr Happy said:


> The difference is that lithium batteries may catch fire if this happens, which would cause more damage than leaking electrolyte from an NiMH cell.



Point taken. After reading everyone's replies, I'm leaning towards continuing to use NiMH.


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## uk_caver (Mar 31, 2013)

*Re: Leaking Eneloop AA cell*



Mr Happy said:


> This seems really strange. Eneloops like other NiMH batteries are completely enclosed in a steel case like a bottle that extends all the way round the negative end without any gaps.


That puzzled me as well, especially looking at the pictures with the 'dry patch' under the wrapper near the positive end.
It's interesting that liquid seems to have seeped/been pulled by capillary action much further between cell and wrapper from the negative end than from the positive end.

Maybe Panasonic would be interested in having this cell back?


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## Rexlion (Mar 31, 2013)

*Re: Leaking Eneloop AA cell*

We may never know the exact cause, but it sounds like a manufacturing error of some sort. It can happen to anything made by imperfect humans.

A L91 is an excellent choice for this application, so I think you may as well switch to that for peace of mind.


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## SilverFox (Mar 31, 2013)

*Re: Leaking Eneloop AA cell*

Hello Zulutime1,

Welcome to CPF.

I am leaning toward overcharging as the cause of the problem. I have had Eneloop cells leak when subjected to a longer term "top off" and it resulted in dampness similar to what you have observed. I didn't use the cells after that and the crusty's were most likely formed by a reaction of the chemicals after the cell was put into the device.

The cell that I had leaked from the positive end and the electrolyte traveled under the wrapping to the negative end but the cell was damp at both ends. Also, there was a very quite hissing that alerted me to the issue. The cell appeared to discharge normally but during a charge cycle it started hissing again. I believe the problem had to do with the vent sticking open after the initial release. Since electrolyte is reduced during something like this the capacity of the cell will also be reduced.

I think this is rather rare. Get yourself a quality charger and you should not see additional problems. Something like the MAHA C-9000 would serve you well.

Tom


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## zulutime1 (Mar 31, 2013)

*Re: Leaking Eneloop AA cell*



SilverFox said:


> Get yourself a quality charger and you should not see additional problems. Something like the MAHA C-9000 would serve you well.



Thanks for the analysis. Until it was pointed out, I actually didn't realize I was using a timer-based charger. I thought it was a smart one all along. So I'm definitely getting a smart charger. I'm going to get the Sony BCG-34 because I don't need anything fancier at this point. Will that work well?


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## Mr Happy (Mar 31, 2013)

*Re: Leaking Eneloop AA cell*

There are several different models of BCG-34 made by Sony: BCG-HLD, BCG-34HRE, BCG-34HS, BCG-34HRMF, etc. They are not all the same, and not all are equally recommended.

The BCG-34HRE looks good, but it seems to be discontinued. The BCG-34HLD is not particularly good by comparison.

I second Tom's recommendation of the Maha C9000. It might seem like it is over specified for simple charging duties, but it works very well and gives peace of mind.


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## SilverFox (Mar 31, 2013)

*Re: Leaking Eneloop AA cell*

Hello Zulutime1,

That charger would be fine for normal NiMh cells. However I would not recommend it for the low self discharge cells like the Eneloop cells.

Tom


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## donn_ (Mar 31, 2013)

*Re: Leaking Eneloop AA cell*

I make it a habit to remove cells from expensive equipment which doesn't get regular use. Any cells. It isn't that difficult to put fresh cells into an instrument that only receives occasional use, and to remove them when I'm finished.


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## VidPro (Mar 31, 2013)

*Re: Leaking Eneloop AA cell*

I see the "digital" device and without even reading i could assume that it was a device that could have parasitic drain. Confirmed when you said it doesnt turn fully off.
then Sealed fully, many of the specs for ni-mh batts say (or used to say) not to put in fully sealed containers. because of tiny ammounts of hydrogen gas that can vent. I cant figure how being sealed would have allowed sooo much electrolyte to leak out, but mabey it dries most the time.

and no i am not excusing the battery, or blaming the user at all. it is just interesting. thanks for the pictures.

how the heck did the bottom become unsealed? cause the can part doesnt even have any seams down there. Like UKcaver is indicating, it really does look like it came from the bottom, not the top where the vent is. my logic says that is pretty hard to have happen ??? 
If there is a hole in the bottom, off center, it might be a reason why/how so much electrolyte got out of the cell. the normal vent releace location is less likely to let out so much juice, unless it is in the nipple down postition, and even then the way it is built the ammount from there would be less.


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## paul.allen (Apr 1, 2013)

*Re: Leaking Eneloop AA cell*



zulutime1 said:


> I didn't even realize I was using a dumb charger. Now I'm going to get something better. Thanks for pointing this out!



On my blog I have a post about NiMh battery chargers, and I explain some ways to spot dumb chargers vs good chargers (with out necessarily having to spend big bucks).

http://www.paulallenengineering.com/blog.html


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## Yamabushi (Apr 1, 2013)

*Re: Leaking Eneloop AA cell*

Consider carefully removing the wrapper to find the actual point at which the case leaked.


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## smooth2o (Feb 5, 2015)

*Do the Eneloops leak? And other questions*

I'm sure this has been covered somewhere, but I'm new to rechargeables (yeah, I know, for a techie guy that's something huh?).

What can I expect from Eneloops? Do they leak, under what conditions? Any other bad characteristics you can think of?

I know Alkalines leak but I've been seeing notices on batteries packaging that now says that you can send in your light and they will replace it if they leak.

What has caused this change in batteries? I have lost several lights to alkalines leaking and I am protective of all my radios, GPSs and my golf range finders among many other electronics. So what are the general guidelines with respect to some of the bad characteristics of batteries (aside from the dangerous stuff covered elsewhere)?


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## tandem (Feb 5, 2015)

*Re: Do the Eneloops leak? And other questions*

Low self discharge NiMH cells employ what is termed a _starved electrolyte _design - essentially it's damp-dry rather than the flooded-wetter (and more caustic) design used in Alkaline primary cells. 

If an Eneloop somehow ruptures over time (not known to be an issue of concern) the innards will not ruin your device.

Under significant abuse any cell containing stored energy might rupture / vent. Again this isn't a significant concern with NiMH cells.


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## SilverFox (Feb 5, 2015)

*Re: Do the Eneloops leak? And other questions*

Hello Smooth2o,

Under continuous trickle charging Eneloop cells will leak gas, or vent as it is commonly caused. No fluids come out.

Tom


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## MidnightDistortions (Feb 5, 2015)

*Re: Do the Eneloops leak? And other questions*

It's rare and probably will only happen if you're feeding a huge amount of current into an already charged NiMH cell.


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## CuriousOne (Feb 6, 2015)

*Re: Do the Eneloops leak? And other questions*

It's easy to diagnose why battery leaked.

Put a couple of vinegar drops over the leaked "liquid" even if it is already dried to powder state. If there will be heavy bubbling, this means that battery chemistry was OK, but leak occured due to overcharge/gas pressure rise/etc, which caused integrity of battery to break. If there will be no or little bubbles, this means that chemistry was exhausted, so leak can be associated with aging and or bad manufacturing quality.


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## lunas (Feb 6, 2015)

*Re: Do the Eneloops leak? And other questions*

alkaline batteries are made with zinc and manganese dioxide with an electrolyte of potassium hydroxide or lye the white crystals found outside batteries is potassium carbonate a salt both substances are water soluble and both corrode metal.

NiMH also uses potassium hydroxide...

only ones that are leak proof are lithium based they also dont use potassium hydroxide 

only lead acid and zinc air use acidic compounds.


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## Drakemoore (Feb 6, 2015)

I personally have never had a NiMH battery leak, but I have seen the 'super heavy duties' and Alkaline batteries leak from time to time. Admittedly I only own a handful of Nimhs and that could be why I've never seen one leak.


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## WalkIntoTheLight (Feb 6, 2015)

Drakemoore said:


> I personally have never had a NiMH battery leak, but I have seen the 'super heavy duties' and Alkaline batteries leak from time to time. Admittedly I only own a handful of Nimhs and that could be why I've never seen one leak.



Leaking NiMH's must be pretty rare. I have hundreds of NiMH cells, and have never seen a leak. OTOH, I have dozens of alkalines (mostly unused), and have seen several leaks just in the past year (luckily, all inside their packaging).


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## smooth2o (Feb 6, 2015)

*Re: Leaking Eneloop AA cell*



uk_caver said:


> The datasheets for the HR-3UTG, HR-3UTGA, and HR-3UTGB actually refer throughout to a 2A/1C charge rate, .



That said, is there any problem with the Nitecore D2 charging Eneloops as it charges at .75A max?


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## Phlogiston (Feb 6, 2015)

*Re: Leaking Eneloop AA cell*

I've only seen NiMH cells leak once - an entire pack of four crap no-name cells that were included with some other product. I had much better cells in service already, so I threw the crap ones in a box for a couple of years. When I came across them again, all four of them had leaked in comprehensive fashion, so I'm glad I never used them. 

Goodness knows who made those cells, but they didn't have a clue what they were doing. New and unused NiMH cells should never, ever do that.

Mind you, I've had a lot more alkaline cells leak over the years, so NiMH is still well ahead on that count. My Eneloops have been absolutely impeccable.


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## lunas (Feb 6, 2015)

*Re: Leaking Eneloop AA cell*



smooth2o said:


> That said, is there any problem with the Nitecore D2 charging Eneloops as it charges at .75A max?



it should be able to charge at .35 as well hold the mode button down for 5 seconds it should turn into the low mode my d4 has that feature...


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## oKtosiTe (Feb 10, 2015)

*Re: Leaking Eneloop AA cell*



lunas said:


> it should be able to charge at .35 as well hold the mode button down for 5 seconds it should turn into the low mode my d4 has that feature...


Most chargers terminate better at higher charge rates, however, and Eneloops can be charged at up to 1A with no problems whatsoever.


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## josekym (Oct 18, 2021)

oKtosiTe said:


> *Re: Leaking Eneloop AA cell*
> 
> 
> Most chargers terminate better at higher charge rates, however, and Eneloops can be charged at up to 1A with no problems whatsoever.


Recently, I re-charged a set of 4 Eneloop cells (white, 1900mAh, genuine - made in China) using LiitoKala Lii-500 charger at 1A per channel. After a while, I noticed popping and sizzling noises coming from the charger. Upon inspection, 2 or the four cells were very hot to the touch and I could tell were "leaking" since there was a small bit or moisture on the (+) end. I let the cells cool down and marked them as unsafe to use and stored them in their plastic holder. After a few days when I went to inspect the cells, the two that leaked were now showing a whitish powder apparently discharged from the (+) end. However, the same cells are still holding 1.33V. I no longer wish to use them, though.

I use the same Lii-500 charger @1A per channel to top-up my Eneloop Pros and made in Japan Eneloops without issue, so I am suspecting the quality of the China made cells is really lesser than the Japan made ones.


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## uk_caver (Oct 18, 2021)

Unless the cells have only done a few cycles, to have two have issues at the same time would make me suspect a [possibly transient] charger failure rather than a cell issue.


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