Most Efficient longest run time 18650 & 21700 lights

xxo

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What are the 18650 and 21700 lights with the the longest verified run times at around 300 lumens?

Links to tests with run time graphs would be much appreciated.

Thanks!
 

kerneldrop

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I'm tagging in for this.
I'm curious to see what is suggested and why
Suggestions will have to be based off LED and driver design.
 
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Hooked on Fenix

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Nitecore MH25 v.2 has to be in the running for 21700 with 8.5 hours at 300 lumens. Nitecore lights tend to dim down in the last half hour to conserve power so it’s probably closer to 8 hours regulated.
 

kerneldrop

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A buck driver or direct drive -- without reverse voltage protection and without low battery protection -- providing 300 lumens should be the most efficient. The reason is, is that all that gadgetry --including multi-mode features -- require energy to work.

Then you have to factor in the LED. I believe an LED with a lower forward voltage requirement should be more efficient than one with a higher voltage requirement. An example, when looking at Nichia's datasheets, the 519a will be brighter than a 219b when powered by the same wattage.

@idleprocess and @LEDphile will know way more than me.
 

xxo

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I think we should stick to single cells, otherwise we would get into to the weird soda can and 12P Maglite territory
Yeah, I was thinking one cell otherwise whatever has the most cells would win.
 

xxo

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A buck driver or direct drive -- without reverse voltage protection and without low battery protection -- providing 300 lumens should be the most efficient. The reason is, is that all that gadgetry --including multi-mode features -- require energy to work.

Then you have to factor in the LED. I believe an LED with a lower forward voltage requirement should be more efficient than one with a higher voltage requirement. An example, when looking at Nichia's datasheets, the 519a will be brighter than a 219b when powered by the same wattage.

@idleprocess and @LEDphile will know way more than me.
Just trying to get an idea of what the better lights currently on the market are capable of. I thought around 300 Lumens would be good for comparison since most regulated lights could easily sustain that level of output.
 

kerneldrop

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Just trying to get an idea of what the better lights currently on the market are capable of. I thought around 300 Lumens would be good for comparison since most regulated lights could easily sustain that level of output.

You’d be splitting hairs. A multi-mode light will limit current to get a specified estimated output that is based on the amount of watts the LED needs to achieve the desired output.

How you get there may differ, but ultimately the amount of current being used will be similar across all brands.
 
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