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    vol
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    Maximum lumens of flashlights using AA or AAA batteries?

    Does anyone have idea about the maximum lumens a flashlight is capable of, which uses several AA or AAA batteries? I have one that claims to be 800lm but obviously much less in reality, however I have no idea how many lumens it actually has. If I know the maximum lumens, I'll know all those claiming more than that are lies, and that if I want brighter ones, I can't expect to use AA/AAA's.

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    Senior Member bud16415's Avatar
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    I don’t think it works that way. It will depend somewhat on how many batteries are used and at how fast of a discharge rate they will be used up at.

    Someone might know the light output of some of the common lights that use those size batteries though. Seems like most things today plaster specs all over the package hoping to have you pick one that’s a little higher.
    What's not in your legs needs to be in your gears.

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    Senior Member Looigi's Avatar
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    Last edited by Looigi; 12-20-12 at 08:02 AM.

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    The Recumbent Quant cplager's Avatar
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    Just to add to the above answers, AA or AAA are effectively telling you how much stored power you have. If you put three AAA batteries in series, then you have 4.5V which can power some pretty bright lights. Just probably for not very long. Putting three in parallel means you have the same 1.5V as a single battery, but it will last longer (than a single battery).
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    Collector of Useless Info
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    Volts is different from stored energy. Nowadays, a buck-boost power supply used to supply a modern LED light takes in watts (more current at lower voltage and less current at higher voltage) and puts out watts. There are many types of LED's that you can drive with different wattage, but the common high-efficiency single LED's can be driven at 3-5 watts typically and put out different lumens for that power input.

    Alkaline AA batteries have about 1.5 watt-hour of storage capacity each. Lithium have more for the same size.

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    Senior Member Looigi's Avatar
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    Quote Originally Posted by cycle_maven View Post
    Volts is different from stored energy. Nowadays, a buck-boost power supply used to supply a modern LED light takes in watts (more current at lower voltage and less current at higher voltage) and puts out watts. There are many types of LED's that you can drive with different wattage, but the common high-efficiency single LED's can be driven at 3-5 watts typically and put out different lumens for that power input.

    Alkaline AA batteries have about 1.5 watt-hour of storage capacity each. Lithium have more for the same size.
    Don't forget the effect of the equivalent series resistance (ESR) of different types of batteries. The higher the current the more power is wasted in battery. There is a wide variation between types of batteries. Carbon zinc are very bad, alkaline are better, NiCd and NiMH are much better, and LiPo and Li Ion are way better in the max currents they can delivery.

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    vol
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    Thanks for the replies. Thanks for all the links. From the pictures, it seems my "800LM" is only around 300LM. It's good to know, from the links by davidad, that 3xAA can achieve >900LM (I did notice this note: "Alkaline batteries should be used on Low and Medium modes only, due to high internal resistance."). They are also based in China, so wonder how reliable their lumen claims are.
    Last edited by vol; 12-20-12 at 03:30 PM.

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    Because I thought I could ks1g's Avatar
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    More complicated than that - beam pattern determines where the lumens (technically, photons) the LED is emitting wind up, and if they are doing you any good. Hence a "300L" light may be more useful than an "800L" model. At least across different vendors. Within a single source (at least those that want to be in business for a while), bigger may actually be better. Also possible to be too big (turn night into high noon on technical singletrack probably >> for use on suburban bike paths). Re: "based in China" and "reliable claims" do not belong in the same sentence unless modified with "not", "un", or equivalent negation.

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    Senior Member Looigi's Avatar
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    Quote Originally Posted by ks1g View Post
    lumens (technically, photons) .
    Nope. Units are different.

  11. #11
    Don from Austin Texas
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    I have had it with AA or AAA batteries for my bike lights. USB rechargeable is the way to go.

    Don in Austin

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    Certified Bike Brat Burton's Avatar
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    I think you'd have better luck just sticking with reputable sellers. The maximum lumen output is determined by the LED model and BIN designation and the level to which its driven. The suitability of using AAs or AAAs is dependent on how the light engine is designed - not the LED itself.

    My situation is a little unusual in that the light engines in my 10W lights are designed to accept a 12V input, but that was one reason I picked them. Higher voltage requires fewer amps to produce the same wattage and AA cell have no issue keeping up with the amperage requirement needed to supply less than 1amp at 12V.

    And since I still keep about 50 rechargable AA cells kicking around for other uses - I can drop 10 of them in a plastic battery pack case designed for a radio and use it to power a 10W headlamp for 4 hours. Actually it'll power two for a while, and thats over 1,600 lumens. So better not to use batteries to decide if lumen output is exaggerated or not.
    Last edited by Burton; 12-22-12 at 09:03 AM.

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    And just to cover all bases, I'd like to point out cooling as well. Some lights are better designed in this regard than others. LED's which are properly cooled run more efficiently.

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    Quote Originally Posted by vol View Post
    Thanks for the replies. Thanks for all the links. From the pictures, it seems my "800LM" is only around 300LM. It's good to know, from the links by davidad, that 3xAA can achieve >900LM (I did notice this note: "Alkaline batteries should be used on Low and Medium modes only, due to high internal resistance."). They are also based in China, so wonder how reliable their lumen claims are.
    Intl-outdoor seems to be trusted by the folks on Budget light forum.
    Some of the figures are at the LED and some are out-the-front. You need to research Cree to find out which the manufacturer is using.
    1200 to 1800 lumens from a single XM-L is not possible.

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    vol
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    Seems most of you don't mind having to recharge the batteries frequently? I don't feel like having to remember to charge batteries before a ride. It takes hours to recharge, and you have to take care not to overcharge. Do you guys just plug in batteries into your computers every day as a habit?

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    Certified Bike Brat Burton's Avatar
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    Quote Originally Posted by vol View Post
    Seems most of you don't mind having to recharge the batteries frequently? I don't feel like having to remember to charge batteries before a ride. It takes hours to recharge, and you have to take care not to overcharge. Do you guys just plug in batteries into your computers every day as a habit?
    Personally I hate wondering if I have enough tuntime so deal with battery capacities that mean I might have to charge once or twice a week max. Not only do I get more piece of mind - the batteries will last longer too. So USB devices with a run time of two hours or less aren't something I like myself.

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    I have one of these and 215 lumens is extremely bright. There are many models that are brigher.

    Fenix

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    Complicated physics and optics aside, I'd love to see a 2 x AA flashlight brighter than the Fenix L2D

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    Vegan on a bicycle smasha's Avatar
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    http://en.wikipedia.org/wiki/Luminous_efficacy

    anything that claims to produce more than 683 lm/W is science fiction. as a point of reference, an XML T6 is about 40% efficient, producing about 270 lm/W.

    the battery type and number of batteries (chemistry, voltage, Ah, etc) will dictate how much power is available to the light, and how long that power will last.

    then there are losses on the optics, the electronics, the batteries, the LED, the contacts...
    "When I see an adult on a bicycle, I do not despair for the future of the human race." - H.G. Wells

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    Certified Bike Brat Burton's Avatar
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    Quote Originally Posted by smasha View Post
    http://en.wikipedia.org/wiki/Luminous_efficacy

    anything that claims to produce more than 683 lm/W is science fiction. as a point of reference, an XML T6 is about 40% efficient, producing about 270 lm/W.

    the battery type and number of batteries (chemistry, voltage, Ah, etc) will dictate how much power is available to the light, and how long that power will last.

    then there are losses on the optics, the electronics, the batteries, the LED, the contacts...
    The references in that Wikipedia link are already 3 years old, but regardless - I'd jump on any 10W light that was producing 683 lm/W - or even 270 lm/W!

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    Vegan on a bicycle smasha's Avatar
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    Quote Originally Posted by Burton View Post
    The references in that Wikipedia link are already 3 years old, but regardless - I'd jump on any 10W light that was producing 683 lm/W - or even 270 lm/W!
    don't worry about the date... it's still a physical fact that 1W of electrical energy at 100% efficiency can produce, at most, 683 lm.

    generally, as power and heat increases, LED efficiency decreases. that's why the 10W LEDs will be less efficient than 2-3W LEDs.
    "When I see an adult on a bicycle, I do not despair for the future of the human race." - H.G. Wells

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    vol
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    Quote Originally Posted by smasha View Post
    the battery type and number of batteries (chemistry, voltage, Ah, etc) will dictate how much power is available to the light, and how long that power will last.
    So, does it mean alkaline AA/AAA are less powerful in producing lumens?

  23. #23
    Vegan on a bicycle smasha's Avatar
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    Quote Originally Posted by vol View Post
    So, does it mean alkaline AA/AAA are less powerful in producing lumens?
    numbers from wikipedia...

    AA - Alkaline batteries - 1.5V from 1700 - 3000 mAh (up to 4.5Wh)
    AAA - Alkaline batteries - 1.5V from 250 1200 mAh (up to 1.8Wh)

    18650 - li-ion - 3.7V from 22003400 mAh (up to 12.58Wh)

    in other words, an 18650 can hold a lot more energy (and produce more light, for longer) than AA or AAA batteries.
    "When I see an adult on a bicycle, I do not despair for the future of the human race." - H.G. Wells

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    Certified Bike Brat Burton's Avatar
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    Quote Originally Posted by smasha View Post
    don't worry about the date... it's still a physical fact that 1W of electrical energy at 100% efficiency can produce, at most, 683 lm.

    generally, as power and heat increases, LED efficiency decreases. that's why the 10W LEDs will be less efficient than 2-3W LEDs.
    I was trying to pull your leg a bit. AFAIK we still haven't reached the theoretical limit for LED output which is quoted in that article as being only 260 to 300 lumens per watt, which is quite a bit less than the numbers you posted. So if you know where I can get any of those super emitters you've referred to - I'm in!

  25. #25
    Certified Bike Brat Burton's Avatar
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    Quote Originally Posted by smasha View Post
    numbers from wikipedia...

    AA - Alkaline batteries - 1.5V from 1700 - 3000 mAh (up to 4.5Wh)
    AAA - Alkaline batteries - 1.5V from 250 – 1200 mAh (up to 1.8Wh)

    18650 - li-ion - 3.7V from 2200–3400 mAh (up to 12.58Wh)

    in other words, an 18650 can hold a lot more energy (and produce more light, for longer) than AA or AAA batteries.
    Thats a bit like saying since a quart is smaller than a gallon - a gallon is better. AAs and AAAs are physically smaller than 18650 batteries - of course they hold less energy! It takes more of them to do the same job, but it still breaks down to total watt hours, and I have no problem running 10W LEDs off AA cells. More batteries to charge, and heavier than lithium, but no other issues.
    Last edited by Burton; 01-02-13 at 11:15 AM.

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