Fenix LD20 and battery options

I've been looking for a good AA light to compliment my collection of CR123 lights and I pretty much had my heart set on the LD20, unfortunally I discovered after some searching that the light supposedly doesn't function properly with Energizer Lithium primaries. This is a big letdown. I know, the first thing you guys are going to say is " just get some eneloops", well that's not in the budget right this moment, I will probably get them in the future, right now I just wondering about alkaline performence. Can anyone tell me what the performence of the LD20 is using high quality Alkalines? I am praticualy intrested in the regulation using alkalines as well. On paper the quark AA tactical seems like a good option but, please don't take this as a bashing on quark, but right now their quality control is just too sloppy for me to consider, I know this from various posts and my own experience with them. But yeah, if any LD20 owners can fill me in on their experience using alkalines I would appreciate it. Oh, and if one was to use lithium primaries do you think the extra voltage would damage or shorten the life of the LED?

LD20 turbo mode is very unreliable on alkalines.

Hello! I have sad news for you.
Alkalines suck in any high powered flashlight.
High power flashlights need high current draw at a reasonable voltage. No alkalines are physically capable of providing that much current, or if they do, the voltage will drop drastically.

I haven't heard that the LD20 doesn't work with lithiums, and I think there have been tests (possibly by CPF user: selfbuilt) showing that lithiums are pretty good (good runtime, but regulation suffers just a little). In the end, I'd still say get rechargeables. They don't have to be eneloops, and on sale, you can get 4 AA rechargeables for about $7 a pack. A good charger goes for anywhere from $15-30. And over the long run, it's cheaper than the $10 per 4 single-use lithium batteries.

And lastly, the Quark AA^2 doesn't do any better than the LD20 on alkalines.

If you have not yet seen it I think all the info you need is right here is selfbuilt's review of the LD10 and LD20.

https://www.candlepowerforums.com/threads/277658

No, it works fine on Energizer Lithiums.

I have the same 'issue' with my Fenix L2D rebel 100.

Until the voltage drops, with, the light will be overdriven.
But that only occurs for the first 20% of runtime with L91 (and more like 10% with EA91)

Turbo & alkalines? Does not work well together.

Her's my experiences with my LD20 (Q5).

Ni-MH are the best. Good runtime, when compared to Lithium primaries, much, much better runtime when compared to alkalines.

Lithium AA's have a slightly higher voltage... 1.7/8v eac, compared to 1.5v for alky's and and ~1.2v for Ni-MH. That being said, the low and medium mode become only slightly lower in perceivable output to the high (not the Turbo). I've found that running the Li AA's on Turbo setting for a few minutes is usually long enough to drop the voltage to allow the return of low and Medium. Until the light is turned off for a period, and the batteries rest.

No such thing as "high quality alkalines" IME. They all tend to leak, not being a matter of how as when. There is no reason to waste your time with them.

As far as capacity goes, I think someone did a review of the Quark AA^2, where they did run time charts. With Ni-MH it was about the stated run time. With Duracell's, it was about 5 minutes of regulation, followed by 30 minutes of steeply declining output. Not worth the money, or the expense of a ruined light.

Thanks guys. That's what I figured. I'm wondering if the extra voltage of the lithium primaries would decrease the lifespan of the LED. Sure the voltage goes down with some use, I'm just thinking what damage could be done after many sets of lithiums primaries being run through it.

My vote is for the NiMh too, in my LD20 gives about 1:35 – 1:40 hour until drop the current and the flashlight is off (with 3000 mAh batteries). I use in my mountain bike without problems and always give me a great and continuous output. I never think of alkalines after read the CPF forum.

Good luck and good purchase, ebow86, you will not regret of the LD20.

Has anyone tested the output with nimh vs L91?
Correct me if i'm wrong, isn't ld20 supposed to be current regulated, so the only harm using L91 would be the loss of lowest low?

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I know everyone has different threshold for budget, but consider that a four pack of eneloops can be had for ~$10 and four lithium for ~$2.50. As to the charger you can get a bundled eneloop charger with four cells for ~$18, or perhaps some kind person will send you such a charger, I image there are many unused in peoples closets.

noisebeam said:

I know everyone has different threshold for budget, but consider that a four pack of eneloops can be had for ~$10 and four lithium for ~$2.50. As to the charger you can get a bundled eneloop charger with four cells for ~$18, or perhaps some kind person will send you such a charger, I image there are many unused in peoples closets.

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Four lithium AA's for $2.50? Did you mean $12.50?

@Goldenlight:

Just wild guess, i think it's for each AA Lithium. If it not it might be sale price to get rid some old stock.


@Ebow86:
Short question for Eneloop VS Alkaline,

The Alkaline tend to produce gradually down output, on the other side Eneloop with produce constant output. Also you will get longer runtime on set of eneloop.

You could see the output graphics on LD20 running on pair of Alkaline VS pair of Eneloop. Graphics below taken from Selfbuilt LD10 & LD20 R4 review:

Hi Everyone, I'm new here and am reviving an old thread. I recently bought a Fenix LD20 (R5 version) and also bought Eneloop AA (1500) batteries. My question is I only get run time of about 30 minutes on turbo till the flashlight dies with these batteries. How long of a run time should I expect (cause 30 minutes seems pretty low)? These are batteries that I charged overnight and tested in the LD20. Any help would be great. Thank you.

I suspect you might get a better answer if you post in the Flashlight Electronics - Batteries included sub forum. It does seem unusual. What charger are you using? Also do you have a battery tester which measures the charge level of the eneloops? It might simply be a case of a certain break in period being required for the eneloops although I have never experienced that with my eneloops. If it is not the batteries or the chargers then is there the possibility that there is a problem with the light?

Harry999 said:

I suspect you might get a better answer if you post in the Flashlight Electronics - Batteries included sub forum. It does seem unusual. What charger are you using? Also do you have a battery tester which measures the charge level of the eneloops? It might simply be a case of a certain break in period being required for the eneloops although I have never experienced that with my eneloops. If it is not the batteries or the chargers then is there the possibility that there is a problem with the light?

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Thanks for replying Harry999. I may post in the batteries included sub-forum as well.

I'm using two different chargers, but they look like they are made from the same factory because all the directions/charging times are exactly the same on both (They are Lenmar NoMemPro and UltraLast. They physically look the same and say they charge Ni-MH batteries fully in 7 hours. The output for both for AA is 1.4V DC 210mA.)

I don't have a battery tester, but I might have to get one. Also, I don't think it's the LD20 because I had one pair of eneloops that lasted almost two hours on turbo, but the last 30 minutes the output was dimmer and dimmer. But two batteries in that eneloop 8-pack lasted barely 30 minutes on turbo with the last 10-15 minutes being dim, so I thought they were bad and returned them. I charged those eneloops in the same two chargers.

I think I'll have to get a battery tester. Thanks for pointing me in the right direction.

A battery tester is definitely a good investment for any flashaholic - especially when using lights which use two cells or more. I will look for your thread in the Batteries section. Someone with more knowledge may be sure to provide an answer.

ebow86 said:

Thanks guys. That's what I figured. I'm wondering if the extra voltage of the lithium primaries would decrease the lifespan of the LED. Sure the voltage goes down with some use, I'm just thinking what damage could be done after many sets of lithiums primaries being run through it.

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No, that's not really a problem, just be mindful of the heat on turbo, which applies to any battery chemistry that can hold it on turbo for extended periods.

Before posting in the batteries included section, I decided to do one more test. I charged the AA eneloops longer than the 7 hours the charger says it can achieve a full charge. I charged the batteries almost 24 hours, then tested them in my Fenix LD20 and found that the run time on turbo mode is about an hour to an hour and 15 minutes, then the flashlight gets dimmer for 20 minutes give or take, then goes out. Thus, I think the charger(s) were not fully charging the eneloop batteries and needs to be charged longer in the two chargers that I own.

What kind of chargers do you have, can you charge only one battery in those?
If not and they're charged in pairs, one of the batteries might not be fully charged, and the other might get overcharged.