lithium primary vs. eneloop AAs - newbie questions

[luke_DF]

I read about increased voltage and wonder if lithiums are the way to go for my fenix and quark lights? I don't want alkalines leaking in my lights (happened to me once before - not fun!), but would like to know if these brands don't mind the lithiums?

after reading all the good things people here write about them, I'm set on eventually switching to eneloops, but then - they have lower voltage than alkalines, so I wonder if that means they're not as bright?

 

[HKJ]

after reading all the good things people here write about them, I'm set on eventually switching to eneloops, but then - they have lower voltage than alkalines, so I wonder if that means they're not as bright?

The fact that NiMH are specified at 1.2 volt and alkaline at 1.5 volt does not mean that NiMH always has lower voltage. When running a light at maximum it will usual draw high enough current that NiMH will have the highest voltage (At least after some minutes).

This difference is because alkaline has 1.5 volt unloaded and this voltage will drop when loaded.
NiMH has 1.2 volt when loaded.

 

[Niconical]

I can't think of any 1xAA or 2xAA flashlight that will work with eneloops or alks but not with Energizer lithiums. The only one that does spring to mind is that I might have read somewhere that the Fenix TK40 (8xAA) doesn't like lithiums but I might be wrong on that.

As for eneloops not being as bright as alks, quite the opposite. The voltage of an eneloop is listed as 1.2v, with 1.5v for an alkaline. However, alkalines drop significantly under load (when in use) whereas eneloops start higher than 1.2v and don't really drop much until right near the end. any 1xAA or 2xAA flashlight on high (or sometimes even medium) will be noticeably brighter (and hold it for longer) on eneloops rather than alkalines.

Other than long term storage, emergency bag, car etc, I can't see any reason to buy single use Energizer lithiums instead of eneloops.

EDIT: Actually I should add that the Energizer lithiums tolerate more extreme temperatures than eneloops (or any other nimh and alkaline), but I doubt it gets hot enough or cold enough in the UK for that to be an issue for you, unless you live right up at the top in the coldest parts of Scotland, or in a fridge.

 

[CaseyS]

The original Quarks are designed to lego with different sized battery tubes. The lower voltage head is specified as being compatible with voltages from 0.9V to 4.2 volts, so it will work with alkaline, NIMH, a single CR123a or any single rechargeable Li-Ion battery like an RCR123a, a 17670 or an 18650. It's much brighter on Turbo with a single Li-Ion than it is with a single alkaline or NIMH.

Edit - nevermind, didn't notice the thread title said lithium primary.

 

[frosty]

Don't forget that the Energizer lithiums will give a longer runtime in most lights.

 

[was.lost.but.now.found]

It really comes down to this question, do you want the best performance money can buy or slightly lower performance in exchange for cost savings by using rechargeable batteries? This is a never ending debate here at CPF. Personally, I instinctively use my flashlights less when I'm running on primary batteries in order to conserve power. This makes me sad, so I try to stick with quality rechargeables when I can so I can have guilt free lumenslovecpf.

 

[45/70]

This difference is because alkaline has 1.5 volt unloaded and this voltage will drop when loaded.
NiMH has 1.2 volt when loaded.

Good point HKJ, but I think really, the difference here is that alkaline cell voltage is determined under a much lighter load than NiMH cells.

Actually, an alkaline cell will read close to 1.7 Volts OC, when new. The "1.5 Volt" is derived from alkaline cells being tested under a relatively light load, such as 100mA for an AA alkaline. NiMH cells on the other hand are rated for voltage under a typical 0.4C load, or 800mA for a 2000mAh NiMH cell, thus causing considerably more voltage drop under load.

I posted about this in another thread recently. I'm not real sure about the accuracy of the test figures I stated, but I think they are relatively close to what is used, and demonstrate in part anyway, the difference between alkaline and NiMH cell voltage ratings.

Part of the reason there is such a difference between how alkaline and NiMH cells are rated, is because alkaline cells are pretty much by design, used for low current drain devices. NiMH and NiCd cells on the other hand, have pretty much always been designed and used in higher drain devices like power tools, radio transceivers etc. that have higher current drain. This is reflected to some degree, in how their "nominal" voltage is derived.

luke_DF, I'm not going to steer you one way or the other between lithium primaries and eneloops. Both are good choices for reasons others have already stated. Either of them will handily outperform alkaline cells. Those aren't worth the effort IMO and, as you mentioned, they leak.

Dave

 

[luke_DF]

thank you for your feedback everyone!

 

[TorchBoy]

Actually, an alkaline cell will read close to 1.7 Volts OC, when new.

Lithium primary cells might, but new alkaline cells have a maximum closer to 1.6 V.

 

[45/70]

Lithium primary cells might, but new alkaline cells have a maximum closer to 1.6 V.

I think this has a lot to do with just how "new" an alkaline cell is. I suppose brand may make a difference too.

I haven't tested new alkaline cells in several years, as I really don't use them anymore. Just the same, I remember seeing some "new" alkaline cells with voltages very close to 1.7 Volt. This was with (at the time) a very accurate, calibration checked once a year, bench meter. Yes, 1.6 Volt is probably closer to the "norm".

Dave

 

[Oddjob]

Depends on your usage. If you use the light frequently then NiMh would be more economical. If the light is going to be left in the car or cottage or something like that then Lithium would be the way to go. I personally will take the guilt free lumens with maybe a bit less performance over the cost of primaries.

 

[davidt1]

It takes $1,000 worth of lithium batteries (Energizer brand at $2 each) to equal one Eneloop (1,000 charges).

 

[Paul_in_Maryland]

Re: lithium primaries: Not for incans

I can't think of any 1xAA or 2xAA flashlight that will work with eneloops or alks but not with Energizer lithiums.

Incandescents. Trust me: In 2003, I sacrificed a few bulbs and lamp assemblies from various 2AA incans, all bought from brightguy.com--Pelican, Streamlight, Bright Star, and Underwater Kinetics. Some would hot flash; others would die prematurely. But boy, there were bright while they lasted.