Why are eneloops special again?

[deusexaethera]

They look like just any other NiMH batteries. Can I get a short list of reasons why they're the preferred NiMH batteries on CPF?

 

[Benson]

They are not the preferred choice for all applications. They're LSD (the main benefit), and they do hold voltage well under low to moderate currents, but you can get higher capacity (for low-current lights that will always be charged before use) or higher current (for high-current lights) cells in non-LSD.

 

[bltkmt]

Because of the funny name.

 

[Sgt. LED]

I like that they don't self discharge fast.

It seems like I charge the other types up and set them aside for later use to discover when I am ready to use them they are half flat.

 

[Marduke]

Low Self Discharge
higher voltage under load
lower internal resistance
higher tolerance to abuse and neglect
test at or better than stated capacity

 

[Cuso]

http://en.wikipedia.org/wiki/Low_self-discharge_NiMH_battery

 

[deusexaethera]

Low Self Discharge
higher voltage under load
lower internal resistance
higher tolerance to abuse and neglect
test at or better than stated capacity

Well, that pretty much settles it then, doesn't it?

Have they figured out how to make a true 1.5v NiMH yet, or are eneloops 1.2v like all the others?

 

[shuter]

deusexaethera - "Have they figured out how to make a true 1.5v NiMH yet, or are eneloops 1.2v like all the others?"

I love the Eneloops and use them whenever I can but it would be Really great if they could make them 1.5V.

Does anyone know what is preventing Sanyo and other LSD battery manufacturers from making them 1.5V?

 

[funkychateau]

Nominal cell voltage is determined by battery chemistry. Lithium Primary ~ 3 V, Lead-Acid ~ 2 V, Carbon-Zinc / Alkaline ~ 1.5 V, NiCad / NiMH ~ 1.2 V, Silicon Solar Cell ~ 0.5 V, etc.

deusexaethera - "Have they figured out how to make a true 1.5v NiMH yet, or are eneloops 1.2v like all the others?"

I love the Eneloops and use them whenever I can but it would be Really great if they could make them 1.5V.

Does anyone know what is preventing Sanyo and other LSD battery manufacturers from making them 1.5V?

 

[Badger_Girl]

deusexaethera - "Have they figured out how to make a true 1.5v NiMH yet, or are eneloops 1.2v like all the others?"

I love the Eneloops and use them whenever I can but it would be Really great if they could make them 1.5V.

Does anyone know what is preventing Sanyo and other LSD battery manufacturers from making them 1.5V?

Physics

 

[Marduke]

Well, that pretty much settles it then, doesn't it?

Have they figured out how to make a true 1.5v NiMH yet, or are eneloops 1.2v like all the others?

deusexaethera - "Have they figured out how to make a true 1.5v NiMH yet, or are eneloops 1.2v like all the others?"

I love the Eneloops and use them whenever I can but it would be Really great if they could make them 1.5V.

Does anyone know what is preventing Sanyo and other LSD battery manufacturers from making them 1.5V?

1) NiMH cells are not actually 1.2v. They start out ~1.4v, and will stay ABOVE 1.2v during almost their entire discharge under a moderate load. Alkaline cells on the other hand will start out at 1.5v, and will sag BELOW 1.2v under even a relatively light load.

2) Manufacturers can't just make a battery be any voltage they want. The voltage of the battery is determined by the chemistry uses. NiMH and NiCad are 1.2v nominal, just like lithium-ion is 3.7v nominal.

You couldn't make a cell be something else "just because you want to".

 

[Benson]

deusexaethera - "Have they figured out how to make a true 1.5v NiMH yet, or are eneloops 1.2v like all the others?"

I love the Eneloops and use them whenever I can but it would be Really great if they could make them 1.5V.

Does anyone know what is preventing Sanyo and other LSD battery manufacturers from making them 1.5V?

Yes. They're making NiMH cells, and those are 1.2V/cell. Each chemistry has its own voltage per cell, and there's not much you can do about it. (The electrochemical potential is actually something like 1.3V for NiMH, IIRC, but you always wind up operating below that due to internal resistance, if nothing else.)

An interesting alternative chemistry is available, NiZn, which has about 1.7V per cell -- they could be useful in some applications where a 1.2V won't work. But it's not NiMH.

 

[BigBluefish]

Nominal cell voltage is determined by battery chemistry. Lithium Primary ~ 3 V, Lead-Acid ~ 2 V, Carbon-Zinc / Alkaline ~ 1.5 V, NiCad / NiMH ~ 1.2 V, Silicon Solar Cell ~ 0.5 V, etc.

While lithium promary CR123a batteries are a nominal 3 V, aren't lithium primary AAs (E2s or L91s) something like 1.8 V, and 1.6 V under load? Why is that? Would it be possible to make a 3 V AA lithium primary cell? (I guess there is some very basic, practical reason this isn't done. And sorry, I've gone OT.

BTW, I really like the Eneloops. But how did they come up with that name????

 

[Egsise]

While lithium promary CR123a batteries are a nominal 3 V, aren't lithium primary AAs (E2s or L91s) something like 1.8 V, and 1.6 V under load? Why is that? Would it be possible to make a 3 V AA lithium primary cell? (I guess there is some very basic, practical reason this isn't done. And sorry, I've gone OT.

BTW, I really like the Eneloops. But how did they come up with that name????

You mean the CR AA which is 3V AA size lithium?
http://www.varta-microbattery.be/craa.php

 

[Marduke]

While lithium promary CR123a batteries are a nominal 3 V, aren't lithium primary AAs (E2s or L91s) something like 1.8 V, and 1.6 V under load? Why is that? Would it be possible to make a 3 V AA lithium primary cell? (I guess there is some very basic, practical reason this isn't done. And sorry, I've gone OT.

Lithium primary CR123 and AA's are of a different chemistry.

CR123 lithium primaries are Lithium Manganese Dioxide
AA/AAA lithium primaries are Lithium Iron Disulfide

They do make AA size 3v cells, however most of them are intended for very low drain devices. You can get them over the shelf (two of them) by taking apart a CRV3 cell.

 

[shuter]

Thanks Guys! Great information about the limitations of battery voltages and the comparatively underrated Eneloop voltage. Good to know.

 

[jag-engr]

Low Self Discharge
higher voltage under load
lower internal resistance
higher tolerance to abuse and neglect
test at or better than stated capacity

Don't forget availability. Eneloops are widely available both on-line and in brick & mortar stores (assuming you live near a Costco).

 

[KingGlamis]

Lithium primary CR123 and AA's are of a different chemistry.

CR123 lithium primaries are Lithium Manganese Dioxide
AA/AAA lithium primaries are Lithium Iron Disulfide

They do make AA size 3v cells, however most of them are intended for very low drain devices. You can get them over the shelf (two of them) by taking apart a CRV3 cell.

Also don't forget the 14500 Lithiums that are AA-size and 3.6V.

 

[crofty]

But how did they come up with that name????

Accordin to sanyo, Eneloop = Energy + Loop.

Quirky but I like it, not just a name either there`s meaning behind it too. In fact I like their whole gaia concept.

 

[mdocod]

The advantages of investing in eneloop cells are not going to be obviously apparent to someone unless they have a standard by which to compare to. My experience with other brands and capacities of AA and AAA cells has shown me than the useful life of the average NIMH cell is far lower than expected. Few dozen cycles and one long storage time and they are down hill from there with loss of capacity, high self discharge, voltage suppression, the whole works.

Eneloops are great because you don't have to dedicate any extra brain cells to battery care. Just charge them and use them as you wish, you'll find years later they are still kicking strong without any problems, and then it'll occur to you that it was a good investment after-all