Eneloops in Freezer?

[kay188]

I got my hands on 6x Eneloops the other day.

Would anyone really recommend storing Eneloops in the freezer or fridge rather for long term storage or to increase performance of them?
Or would it just harm the batteries?
Or would it just have no difference at all if you charge one night, freeze them, and then use them the next morning?

If there's no difference in charging them for a few hours or so, and leaving them over night and using them the next morning than freezing them over night, then might as well just not freeze them?

I've stored my Energizer 2300Mah's in the freezer as we all know normal Ni-Mh discharges fast in the first hour after they're done.

I came across this site that tested the batteries:
http://www.stefanv.com/electronics/sanyo_eneloop.html
If you do a search for the word "freezer" you'll come across some things.

Storage temperature is of high importance if you measure self-discharge rate. Higher temperatures substantially increase self-discharging. It is best to store Eneloops as cool as possible to keep the charge in the battery. As a rule-of-thumb, every 10°C increase in storage temperature is equivalent to doubling the storage time. Some R/C pilots in Europe put Eneloops in the freezer, with rather good results.

Any help, or insights with what you do with your batteries would be appreciated!

 

[SilverFox]

Hello Kay,

Welcome to CPF.

Cooler temperatures slow down chemical reactions, so they also slow down self discharge rates...

However, the self discharge rate for the Eneloop cells is so low that I am not sure it is worth the trouble of throwing them in the freezer. I would suggest that you charge them up and use them.

Tom

 

[Mr Happy]

If there's no difference in charging them for a few hours or so, and leaving them over night and using them the next morning than freezing them over night, then might as well just not freeze them?

Also keep in mind that if you take them out of the freezer in the morning you will have to warm them up to room temperature before they will work properly. Cold temperatures may be good for storage, but they are not good for use.

But even for long term storage, I personally would not consider it worth the bother. I have left charged Eneloops sitting for months before use, and I never worry about self discharge. Someone once stored some Eneloops in the car through the Houston summer as a test, and they still had plenty of charge left even after being cooked like that.

The best answer to any concerns about Eneloops losing 20% of their charge in storage is keep a second spare set handy. There's just no need to go through the "charge the night before" protocol. Charge a bunch at your leisure, keep them to hand, and grab some when needed.

 

[kay188]

There's just no need to go through the "charge the night before" protocol. Charge a bunch at your leisure, keep them to hand, and grab some when needed.

Thanks for your insights. I appreciate it =)

Well the "charge the night before" was just an example. Charge at my leisure then pop them into the freezer to store them to help retain their charge better.

What if i instantly use them right out of the freezer?
Would that harm the battery?
Or would performance from them be lower?
I did read that charging them when they're still frozen would be bad though.

 

[Mr Happy]

See this thread: http://www.candlepowerforums.com/vb/showthread.php?t=214389

As mentioned there, NiMH cells perform best at room temperature. Any drop in temperature will lead to less run time and lower output.

 

[Mike Painter]

I've seen nothing definitive about anything but alkalines and they all say it is of no benefit. If you look at the "use by" you will see it is usually seveeral years in the future.
Using them right out of the freezer even if it did not affect performance would be a mistake.
Cold metal attracts moisture and could lead to rusting which would shorten the case life and could drip onto the spells which keep the magic smoke in. Most are water soluble.

 

[kay188]

See this thread: http://www.candlepowerforums.com/vb/showthread.php?t=214389

As mentioned there, NiMH cells perform best at room temperature. Any drop in temperature will lead to less run time and lower output.

Even if i charge them, they get quite warm, then i pop them in the freezer to store them, and when i do thaw them to use them, say a week later or so, i would be better off storing them at 20 degrees charging them before i need to use them?

 

[jasonck08]

Someone should do a test. Pop one in the freezer and leave on in room temperature. Check the voltage every month and see if they last longer in the freezer... Anyone willing to do this?

 

[kay188]

Someone should do a test. Pop one in the freezer and leave on in room temperature. Check the voltage every month and see if they last longer in the freezer... Anyone willing to do this?

I would offer, but i dont have a multimeter :grin2:
And i need all my batteries. =P

 

[Mr Happy]

Even if i charge them, they get quite warm, then i pop them in the freezer to store them, and when i do thaw them to use them, say a week later or so, i would be better off storing them at 20 degrees charging them before i need to use them?

I'd say that the differences one way or another will be so small that, without accurate test equipment, you would be unlikely to notice.

 

[Lynx_Arc]

why buy LSD cells to freeze? you could put them on a l hour charger and top them off faster than they would thaw out I would think.

 

[Yoda4561]

I wouldn't freeze them, I wouldn't imagine the thermal cycling would be good for them long term, and isn't that the whole point? I'd wager if you really wanted, the fridge would be fine, and they'd probably have 90% charge after 2 years that way.

 

[Elliot]

One month ago I posted: "As a test I charged up my 2000+ mAH AA eneloops and stored them in the refrigerator (about 35 F) for a year. I just tested them and they had about 93% capactity left."

I keep half my cells in the frig. Once a year I run the cells through a discharge/charge cycle. I live in a very warm part of the USA.