AA lithium primaries economics

[Buck91]

Well I'm considering thowing in lithiums for the winter months in the AA lights I use for bike commuting, but am rather curious if there is any low-cost, high-capacity Li primaries out there?

I did find some 2900mAh AA's on batteryjunction, but wonder about their quality. Any out there that beat the e2's in capacity and quality?

 

[mdocod]

I've used the NUONs from BJ and they seem fine, $1.25 a piece if I recall...

as for the economics, at that price they ARE actually reasonable when compared to the economics of running alkaline...

A good alkaline AA delivers about 1.5-2WH into a 0.5A load.

A e2 lithium delivers about 3.5W/hours, and most off brand lithium AAs will deliver around 2.5-3 watt/hours into a 0.5A load.

So generally speaking, a lithium cell will deliver around double the useful power, and remain at higher voltage throughout the discharge, (meaning your light stays bright for more of it's runtime.) So alkaline AAs purchased at less than $0.63 each may be a better value, but when it's cold out, the lithium's may end up making up for their higher price in a big way.

 

[Marduke]

How cold we talking?

 

[Buck91]

Temp will, naturally vary. But given the region (SE MI) and my own limitations (as voluntary as they are) I would set a low-bound of 0*F.

Not to say I'd be out riding in that weather, but if I were to be, or out walking a trail or at a bon fire, I supose 0*F is about the lowest I'd be out there...

 

[Marduke]

You might have ok results with rechargeables. They don't like extended use below freezing, but retained warmth in the battery container, and warmth from your hand (for regular flashlights walking) might be sufficient to keep the cells plenty warm. Also, heat generated from a high-power LED will also warm the body and batteries.

 

[Stereodude]

So, where's the best place to buy relatively low numbers E^2 Lithium AA's (assuming you don't want 50 of them).

 

[Marduke]

So, where's the best place to buy relatively low numbers E^2 Lithium AA's (assuming you don't want 50 of them).

Sam's Club sells a 12 pack for $20. $1.67ea is the best price I've seen for e2 lithiums so far.

 

[UnknownVT]

Might want to look ar some actual test performances of the lithium e2 and Duracell 2650mAh NiMH in Chevrofreak's -

Fenix L2D CE and L1D CE runtime graphs

Probably the most relevant are the Max(Turbo) and High graphs for each light - L2D-CE uses 2x AA, and L1D-CE uses 1x AA -
although the e2 lithiums did give longer runtimes - it wasn't by a lot in the L2Dce,
and what really surprised me was the e2 only had marginally longer runtimes in the single AA L1Dce.


However the colder temperature may make a difference on performance in favor of the lithium......

from Energizer e2 Lithium AA pdf -
"Recommended Lithium Operating/Storage Temperature: -40°C to 60°C"

from the Duracell Technical Bulletin pdf on NiMH -
"Performs at extreme temperatures — Capable of

operation on discharge from -20°C to 50°C (-4°F to
122°F) "​

The NiMH discharge curves at temperatures from that Duracell Tech Bulletin pdf -

"Capacity: Effect of Discharge Rate

and Temperature
The ampere-hour capacity of the battery is
dependent on the discharge current and temperature,
as can be observed in Figure 5.3.1. It should be noted
that the delivered capacity is dependent on the cutoff
or end voltage. The delivered capacity can be increased
by continuing the discharge to lower end voltages.
However, the battery should not be discharged to too
low a cut-off voltage (less than 0.9 volts per cell) as
the cells may be damaged (see Section 5.6). The
recommended cutoff voltage for nickel-metal hydride
batteries is 1.0 volt per cell.
Typically, optimum performance of the nickelmetal
hydride battery is obtained between 0°C and 45°C
(32°F and 113°F). The performance characteristics of
the battery are affected moderately at higher temperatures.
At lower discharge temperatures, performance
decreases more significantly, caused primarily by the
increase in internal resistance. Similarly, the effects of
temperature on performance are more pronounced at
higher discharge rates. The capacity of the battery
decreases more noticeably as the current increases,​

particularly at lower temperatures."

Note: optimum performance of NiMH is between 0°C and 45°C (32°F and 113°F).

 

[paulr]

1. Lithium AA's only seem worth using instead of rechargeables in cold weather or in special circumstances where you really need the higher capacity or voltage or shelf life. In normal weather nimh cells perform almost as well, and you can recharge them for far lower operation cost and waste creation.

2. The BJ cells are probably similar to the ones Battery Station used to sell, but discontinued because of their history of catching on fire. Their voltage is a bit higher than Energizer cells and their tested capacity is a bit lower. I still have a bunch of the BS cells that I guess I'll use up eventually, but I wouldn't buy any more of them even if they were available. I do use Energizer lithiums in a few devices but as mentioned, that is because of special requirements. I try to use NiMH cells in practically everything except very low powered devices in which I still use alkalines.

 

[woodrow]

I bought several e2 lithium AA's (energizer brand) with my LP M3 from Batteryjunction. Their price was a little better than SAM's.

AA lithiums at the greatest batteries ever made. They are really nice for the weight they save over alkalines in a 3 or four cell light.

 

[etc]

I got a 100+ quantity off flebay for 75 cents each.

With bulk, you get discounts. Should really get 100-200 to get under $1.

 

[Stereodude]

I got a 100+ quantity off flebay for 75 cents each.

With bulk, you get discounts. Should really get 100-200 to get under $1.

Yes, but that assumes you want 100+. I only want a few for emergency use in a light in a car.

 

[paulr]

If you're talking about energizer l91's for under $1 each, those are likely to be the surplus ones that a bunch of cpf'ers bought and tested earlier this year or so. They seemed to be pulled from equipment and were very spotty, some worked well and others were almost drained. If you're talking about those no-name ones I wouldn't mess with them at this point.

There's really little reason to use lithium aa's in quantity in general though. In multi cell lights, beware of the higher voltage. In smaller lights, consider rechargeables.

 

[David_Campen]

I got a 100+ quantity off flebay for 75 cents each.

With bulk, you get discounts. Should really get 100-200 to get under $1.

As paulr mentioned, you likely got what you paid for - used batteries.

 

[hank]

How about AAAs?

Lighthound has a Chinese "Heter" brand, packed in blister pack.
The price would seem cheap (2/$1.99) but .... lithium worries me a bit.
Anyone tried those or know of a pointer to more info?

I do use Energizer lithiums when camping in the winter, the AAs for flashlights and the AAAs for my old Palm Pilot IIIxe --- for reading during the long winter nights in the tent.

And I like to keep a several dozen lithium AA and AAA cells at least, in the earthquake kit to hand out with emergency/rescue lights and radio use if things are bad in the neighhborhood, while I get the battery/charging system working for the longer term.

 

[flashfan]

I love the Energizer lithium AA and AAA batteries, but I really hate the price. The Sam's Club price sounds great...except I don't have membership (sigh!).

 

[TPA]

FWIW, the product data for the Sanyo eneloops shows that they work BETTER in cold weather. Only 2,000mAh, but rechargable, which almost always works out to be cheaper. Just depends if you'll miss that extra 900mAh the E2's have for your application.

 

[UnknownVT]

FWIW, the product data for the Sanyo eneloops shows that they work BETTER in cold weather.

hmmmm....

I'm not too sure about that -
eneloops are still basically NiMH, therefore should have the same characteristics.

This is from the eneloop AA pdf specifications -

The operating temperature range seems to be the same as regular NiMH?

 

[Marduke]

For non-LSD NiMH, look at page 6 of 9. Given the lifestyle Buck91 needs from these batteries, there appears to be no need for LSD anyhow.

http://data.energizer.com/PDFs/temperat.pdf


Down to 0°C, NiMH would be just fine. They actually prefer it around 10°C

 

[TPA]

Okay, I got it wrong (always willing to admit when I have). Here's the data straight from Sanyo:

So there is a hit at 0C, but it'll still outperform alkalines at this temperature. Lithium batteries will perform better than the eneloops at this temperature. I still say it depends on the application. If you aren't going to need the full capacity of the battery in one session, try the eneloops.