DP-LED 722b

Is their any formula to calculate mathrmatically the lumens from the data of mcd and angle given in the datasheet

See this PAge… Where it says a weighting should be applied… here is the Link,…

http://www.compuphase.com/electronics/candela_lumen.htm

this is what it refers to,

“”“Evaluation

The outcome of the equations (and the calculators based on them) may differ from the data given by a LED or spotlight manufacturer, or from what you measure with a Lux meter, for several reasons. The manufacturer may specify the luminous intensity (in candela or milli-candela) perpendicular to the light source, instead of the average value over the apex angle. Another complexity is that the values for candela, lumen and lux are standardized for light with a wave length of 555 nm, or green light. For LEDs of a different colour, a weighting function should be applied, using a standardized model of the human eye. Standard Lux meters have, at best, only filters for daylight and incandescent light, and may therefore deviate significantly for LEDs (even white LEDs, as the spectrum is not the same as for incandescent lamps).“”“””

Also, IS it true one can calculate the lumens through this formula:

Luminous flux in lumens = Radiant power (watts) x 683 lumens/watt x luminous efficacy

it says here in this LINK.: Luminous Flux

So what would be the Lumens for the LED 5mm in the specs given in the Datasheet by this forumula . can anyone help…
Datasheet: http://underwaterseaplants.awardspace.com/led.pdf

I want to know the Lumens output of 1 LED in the Flashlight…

I will post the schematics as well here… if that can help more…







4V accu, 33ohm inseries with each led, at 3V for the led, 1V for the resistor, that is 30mA, so max 10lm per led still sounds plausable.

Advice of obtaining better headlamp still applies..

Assuming the Vf is 3V, the emitter If at 3V = 6.6mA per spec. Nothing much at all. That’s 20mW per emitter, or 240mW total.

Regular sub-$10 ebay XML lights gives out 40x as much power if that is the case.

Farhaj, let’s just admit that this light gives low output? No need to scratch the head too much over how much lumens it gives.

I completely agree with getting another headlamp instead of debating how many (few) lumens that one produces. Almost anything you buy that he mentioned above will be much better, and if you want a really good one, get the Armytek headlamp from Illumination supply, with the discount its only $80 I think and its up to 1010 lumens.

With the headband idea though…Im not sure what you use it for, but if you are moving around using it like for hiking, for me the headband is absolutely annoying and not very workable, the lights move around/get blocked, feel funny and change directions…not a good idea unless you are using it and not in motion!

That depends.
I recently received and modded this $12.— headlamp
I put a depolished, slightly wider lens in it along with an XP-G2.
Zoomed out it’s a flood without edges, so you don’t have a beam that moves with your head.
I think a wide flood TIR would be best though.

But fleabay also has cheaper headlights, also with built in charger and stuff.

So how many mA flows per led over here… And how much is the power of the flashlight in watts… Can someone calculate out for me and show me here…

This is getting awkward :davie:

Yes, Farhaj it’s probably around and about 0.7 Watt and probably some 40 Lumens
Devide it by 12 when you want to know how much per LED.
This has all been said and done by others in the previous posts in this topic.
It’s 12 ‘strawhat’ LEDs. Very cheap.
You would better buy this then:

It’s $4.80 and has built in charger also.
Looks like 1 Watt LED about 70 Lumen.

Now stop asking the same questions.

Did u check the data sheet I sent earlier… http://underwaterseaplants.awardspace.com/led.pdf
Also the Battery in it is they say have the datasheet here: http://underwaterseaplants.awardspace.com/battery.doc ….

The company claims that the output is between 90-100 Lumens … how is this possible… so thats why I opened the light and got the datasheets for led and the battery from them… they also claim that it has 1 watts power output as written on the outside box… Now, they also claim they have a 3Watts Light as well… so I want to be more sure about its power and lumens before buying it… so, first can you clear out this for me about the first light…

I want to know and use the light for fishing

also, what does spectrum half-width show in the data sheet.

Just go fishing and try it out.
Maybe it works fine for you, maybe not.

I tried for fishing … but could not see clearly in water where even it was little deeper or waves forming… so I came to the conclusion it requires a higher Lumens Power…thats why I want to know and calculation lumens and Watts of the total flash light…

You’re simply not gonna get what you want from these lights. Now I don’t see a solution here if you still want to buy them. You get another DP 5W light (as opposed to 3W currently) and so what? Get another 60% lumens on top of 50lumens = 80lumens? That still won’t help.

Best case scenario, let’s say their claim of 100lumens is true. Then so what? That’s not enough according to you. Add 60% to that => 160lumens, still not gonna help.

You will want lumens in the count of 1000lm when spotting - definitely not gonna get it from these lights. Unless you’re willing to wear a couple dozens of them all at once.

You will also want warm colour for night fishing, it doesn’t bounce on wave so much and blinds you. These lights? They’re like 8000k, very very cold white. Now, you’d want 3500k or close to that region, you’re not gonna get them from generic LEDs.

Seriously though - you need CREE XML at least, in warm tint. My advice to you - try to get someone with a CC or debit card to help you order online. If you can do that, maybe we can help you with your ordering choices.

Does DP have that Cree LEDs flash Lights…

These headlights are very common at the markets in Vietnam and they go for around $4. Regardless of the amount of leds they generally put out an underwhelming amount of light, probably less than 80 lumens but will do the job if you’re working on something up close. They’re just very cheap plastic headlights and there really isn’t anything spectacular about them.The head straps are also very flimsy break easily.

Yesterday, I sat and did some measurements for the FLASHLIGHT… I calculated out the VOLTS and Resistance for Each Mode ( 1 & 2)

Can you guys now have a look and tell me what would be Its WATTS, LUMENS and AMPERES EXACTLY….

The areas of the Battery Side along with the Circuit photo is attached along as well; to get a more clearer image of the Volts in the Battery produced.

Have a look at the readings and the PICS Below:




Your total is about 0.9W at emitter.

At 60lm/W for these emitters, you get 54 lumens.


There you go. Hope you are finally satisfied. :)