Fenix LD20 Question...

JKPinPDX

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Jan 26, 2010
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So I am approx. halfway through my first set of good ole' regular Alkaline AA batteries on this light, which I just purchased this month. I just wanted to make sure my light is working correctly.

I have the light on TURBO MODE most of the time... and so I have just notice that when I switch modes from the low setting (loosened head) to the TURBO/Brightest setting (tightened head) that my light goes bright, then after approx. 3 seconds it dims down a notch???? Is this a default setting on this light? It wont stay on the full brightness and always DIMS DOWN a notch. Is this a feature that happens when the batteries get low? I thought this light had that circuitry where it would stay the full power until the battery is fully depleted. Could it be the TYPE of battery I am using(standard Alkaline AA's) wont give the light its FULL BRIGHTNESS POTENTIAL very long and "throttles down" when the power gets low???

Any of you Fenix LD10/20 Owners out there ever experience this?:thinking:
 

PeaceOfMind

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Aug 2, 2009
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The performance you are describing does not surprise me from Alkaline batteries. They do not perform well under heavy load.

Although the light will do its best to regulate the power to the LED, if the battery is not capable of providing that power in its current state of charge, the light will dim.

Basically your batteries are run down and cannot sustain enough current to put out full power for very long. Alkalines often recover a bit if left to sit, so that's why it doesn't surprise me that the light would kick into Turbo mode for a short time before dimming again.

Other battery chemistries do better at providing the full amount of current/voltage when closer to being depleted. Ex. NiMH, Lithium or Lithium-Ion.

Also, it's worth noting that the advertised run-times are probably not based on alkaline batteries, they are probably based on higher capacity NiMH batteries or similar. Thus, you will not get the advertised runtimes out of alkaline cells. Sorry.
 

Locoboy5150

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Yep, PeaceOfMind has it right on. (I also have an LD20.) Get rid of those alkaline batteries.
 

luke_DF

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I have experienced exactly the same thing happening with my LD20 as the alkaline cells (un)gracefully reach the end of their life. a fresh set of batteries provided temporary solution, but really that's just another reason for me to look forward to switching to eneloops in the near future :)
 

JKPinPDX

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So we should use the RECHARGEABLE type batteries if possible right? Costco has a Duracell Pak right now for $20 which includes.... 4xAA's and 4xAAA's PLUS charger. I do use this light alot (along with its smaller brother the LD10) I just got these lights, I love them both... I was just curious what type of batteries you LONG-TIME owners have/are using with these lights. :popcorn:
 

jblackwood

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If you're careful and look at the tops of those Duracell rechargables from Costco, you might find that the white topped ones are really repackaged Eneloops. Just get the packs without the charger and invest in a sweet Maha C9000. Your cells will last virtually forever. Don't waste your money on the chargers that are packed in with the batteries.

You'll find lots more people who are knowledgeable about batteries in the actual battery forum.
 

Locoboy5150

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Nov 3, 2009
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I only use Sanyo Eneloop or the relabeled versions of them marketed by Duracell and referred to on here as "Duraloops." They are 2000 mAh NiMh AA cells and worth every penny over regular disposable alkaline batteries. They simply do not leak, unlike alkaline batteries.

There are several threads in the batteries forum that show how to tell if you're looking at genuine Duraloops or the Duracell labeled Ray-o-Vacs. The Duraloops are definitely much better and last much longer than the relabeled Ray-o-Vacs.
 
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