ATTN: SilverFox And Others: Hybrid NiMH And Charger Questions.

[Gene]

I just recently converted to Eneloops and absolutely love them. I had a few questions though.

I know regular NiMHs are best stored partially discharged. Does this also hold true with Eneloops? If that's true, doesn't that somewhat defeat the purpose of these hybrids?

I've been charging mine with the MAHA #MH-C401FS independant channel charger and it seems to work very well. Is there a better solution?

Lastly, how are the other brands of hybrids performing compared to the Eneloops and are there any C and D cell hybrids in the works? Thanks much.

 

[SilverFox]

Hello Gene,

We don't know that much about the Eneloop cells. We have been storing them fully charge for the the last year and a half and there doesn't seem to be any issues, but it is a little early to know for sure.

The best charger is one that charges in the 0.5C- 1.0C range and keeps the cells cool.

No C or D cells in the works, and testing is underway with some of the other low self discharge cells.

Tom

 

[barkingmad]

Not sure if people are getting a little 'over concerned' about battery storage - normal NiMH *will* be partially discharged after the first 2-4 weeks anyway?

Eneloops discharge far slower - but my advice would be to charge them and use them but don't worry about their storage apart from ideally keeping them around room temperature (if possible and not in a fridge / freezer) and top them up after a year or so.

If you need batteries for 'storing' the Eneloops are still a good choice and should have about 85% capacity after 12 months but if you are looking for batteries to store for emergency use / much longer term then AA lithium primaries are probably the best choice as they have extremely low self discharge.

 

[ltiu]

Eneloops discharge far slower - but my advice would be to charge them and use them but don't worry about their storage apart from ideally keeping them around room temperature (if possible and not in a fridge / freezer) and top them up after a year or so.

I am sure this has been said many times before but if you don't mind, please elaborate "why" not put in the fridge?

Thanks.

 

[barkingmad]

I am sure this has been said many times before but if you don't mind, please elaborate "why" not put in the fridge?

Thanks.

Cold temperature storage can in fact harm batteries if condensation results in corroded contacts or label or seal damage. To maximize performance and shelf life, store batteries at normal room temperature (68°F to 78°F or 20°C to 25°C) with moderated humidity levels (35 to 65% RH). Source: Energizer.

 

[Gene]

Thanks Tom. The MAHA 401 seems to do well as I never use the fast charge and the Eneloops are cool when the charging is done.

barkingmad,
Battery storage is VERY important to me as I have electronic devices that I don't use daily or even weekly and I was always tired of regular NiMHs being almost exhausted when I went to use them. I also hated the recharging ritual every couple of weeks. I know some do but not me!

I also store a small light in each of my jackets and one in my motorcycle for emergencies. With the price of Eneloops coming down to around Lithium primary cost, I like the fact I can recharge them and that pays for the expense. I really like these things!

 

[Eugene]

I'm doing the same. I have different electronic gear, scanner, two way radios, etc that don't get used very often. I put eneloops in them in January and pulled them out last month for a couple trips and everything worked fine.
I standardized on Eneloop and two sets for everything and charge one set on the slow cycle while the other set is in the gear, then put the charged set in my bag as a spare. if I use anything then I swap battery sets and slow charge the used set. I plan to top off maybe every 6 months but usually pull something out before that so I just do the top off from use. I put a little card with each set and note the date of the last charge so if I see something past 6 months I can top them off. So far everything is good.
I have an HHGreg store near me who sells the Eneloop for $7.99 per 4 pack so they are the best cost for me.
I like the fact that the 401 has a fast mode so if I'm ever out and run one set low then I could fast charge if necessary.
I plan to follow silverfox's suggestion of a full cycle every 20 or so top offs (which might take a couple years) so my little card in my packs has 20 blanks for marking top off dates so when it gets full I will know to maintenance them. Plan to get the MAHA 900 sometime to do that (maybe bonus time next year)

 

[barkingmad]

Thanks Tom. The MAHA 401 seems to do well as I never use the fast charge and the Eneloops are cool when the charging is done.

barkingmad,
Battery storage is VERY important to me as I have electronic devices that I don't use daily or even weekly and I was always tired of regular NiMHs being almost exhausted when I went to use them. I also hated the recharging ritual every couple of weeks. I know some do but not me!

I also store a small light in each of my jackets and one in my motorcycle for emergencies. With the price of Eneloops coming down to around Lithium primary cost, I like the fact I can recharge them and that pays for the expense. I really like these things!

Absolutely agree - so Eneloop LSD cells are the way to go except if you would need to store them for potentially 'years' in emergency type devices then you would use Lithium primaries.

With Eneloops at 1 year they should have around 85% capacity remaining and about 70-75% after 2 years (stored at normal room temperature - i.e. around 20 degrees C).

I still would not stick them in a fridge...

 

[tarponbill]

Does this information apply to the RayOvac Hybrids found at Walmart, or are they different from Eneloops. Looking to buy some of these long storage batteries in the near future for my light use emergency gear. Right now I use Lithium, but would like to cut down the cost.

Is either the Eneloop charger or the Hybird charger that comes in a bundle with 4 batteries any good? The Eneloop package implies it's dual channel, the Hybrid seems to say the same, charges two batteries at a time.

 

[coppertrail]

Cold temperature storage can in fact harm batteries if condensation results in corroded contacts or label or seal damage. To maximize performance and shelf life, store batteries at normal room temperature (68°F to 78°F or 20°C to 25°C) with moderated humidity levels (35 to 65% RH). Source: Energizer.

I partly agree with this, only the condensation part. Cold storage can actually increases the overall life of the cells by slowing NiMH chemical decomposition and self-discharge.

To eliminate the condensation risk, store each cell in its own snack sized Ziplock bag. I do this and haven't had any problems.

Another option is to, say, store them in packs of eight. If you need to remove and use only 2, let the remaining 6 warm to room temperature before putting them back into cold storage. This allows time for the condensation to evaporate, and thus they'll be dry when placed back into cold storage.

 

[chimo]

I will add a question to this thread. Perhaps Tom has already examined this.

If you take a one year period, IIRC, LSD cells have shown to have most of their self discharge in the first few months and then self-discharge rate decreases.

What are the effects of intermittant use on Low Self-Discharge (LSD) type cells?

If that "rest" is disturbed by an intermittant load, does the higher rate if discharge seen early after recharging recommence?

My gut instinct would lead me to believe that it would due to the disruption of the chemical process.

I have several sets of these LSD cells (Eneloop and Rayovac) and am curious.

Paul

 

[SilverFox]

Hello Paul,

My gut instinct is similar to yours, but no testing has been done on this.

Tom

 

[chimo]

Thanks Tom. Makes me wonder about using these for those stand-by devices that draw microamps. :thinking:

Paul

 

[zipplet]

As far as I am aware, intermittent use WILL NOT suddenly restart the fast self-discharge seen in the first month of storage. Think of it like a reaction of acid with magnesium - at first it bubbles furiously, then it slows down. If you then remove the magnesium, trim a bit off, and place it back - does the reaction speed up again? No.

Eneloops can even be used in digital clocks and such, I am tempted to buy some AAA eneloops for my outdoor weather sensor, they should not leak like alkalines (it's exposed to temperature extremes).

 

[barkingmad]

I partly agree with this, only the condensation part. Cold storage can actually increases the overall life of the cells by slowing NiMH chemical decomposition and self-discharge.

To eliminate the condensation risk, store each cell in its own snack sized Ziplock bag. I do this and haven't had any problems.

Another option is to, say, store them in packs of eight. If you need to remove and use only 2, let the remaining 6 warm to room temperature before putting them back into cold storage. This allows time for the condensation to evaporate, and thus they'll be dry when placed back into cold storage.

That's really my point - with LSD batteries (Eneloop, Hybrio etc.) the self discharge is so low already and it seems such a hassle for so little benefit to put them in the fridge.

Cells perform worse when cold - so you need to let them warm up anyway and unless you can guarantee there is no air / moisture (which I can't see how you can unless they are vaccuum sealed with silica gel) they could corrode etc.

 

[chimo]

zipplet, I'm not sure your chemical reaction example is directly transferrable to the chemical reaction in LSD batteries, but it may be possible. It would be nice to see some real testing data on these.

Paul

 

[Eugene]

Absolutely agree - so Eneloop LSD cells are the way to go except if you would need to store them for potentially 'years' in emergency type devices then you would use Lithium primaries.

Even my store for years devices I put in Eneloop because I pull them out every 6 months or so and test them out for a bit so I top off the charge afterward.

 

[Eugene]

Plus it seems like a waste of fridge space and baggies. The couple % you save in discharge you could easily just top them off every 6 months.

 

[radellaf]

Figuring that like most batteries these will last about 5 years, isn't it kind of a waste to use them in microcurrent applications where they might go through 10 charge cycles before dying of old age?

Alkalines do have their place.

 

[Gazoo]

Figuring that like most batteries these will last about 5 years, isn't it kind of a waste to use them in microcurrent applications where they might go through 10 charge cycles before dying of old age?

Alkalines do have their place.

10 charge cycles would be equal to at least 10 alkaline batteries. If I am not mistaken, I think the math speaks for itself. Plus I have had bad luck with alkaline batteries leaking. I have replaced almost everything I have that uses alkaline batteries with eneloops, such as remote controls, a wireless keyboard and so on. I have also replaced almost all of my aging NIMH batteries with eneloops.