Most efficient white led at low current?
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deadrx7conv
Enlightened
Repeat of what JC said.
What driver or battery did you use to get .26ma? What lumen output?
Typically, 5mm LEDs run at 20ma(notice the missing decimal) or .020A
Reminds me of a phone bill:
http://youtu.be/D2isSJKntbg
What driver or battery did you use to get .26ma? What lumen output?
Typically, 5mm LEDs run at 20ma(notice the missing decimal) or .020A
Reminds me of a phone bill:
http://youtu.be/D2isSJKntbg
newer high end brand LEDs can give out usable light down to 0.1ma. The trick is having a reflector and night adjusted eyes. You should try direct driving an LED off 2 nimh batteries and see how long and low it goes before unusable.
Whether an LED needs 0.26mA or slightly more is pretty irrelevant. You win no prize for small fractions of a mA, nor do you even save power when using power to post and us to reply. Seeking some exotic part for this purpose does not seem logical nor beneficial in any way.
Last edited:
deadrx7conv
Enlightened
http://www.candlepowerforums.com/vb/showthread.php?89607-White-LED-lumen-testing This thread is a good read. You might find your answer. I'd wager that you'd want the smallest LED that you can find since efficiency below 10ma is lame for larger LEDs. Seems they need some power to light the whole die and start working. You should look for some 3mm or 5mm LEDs from Nichia, The Shack, Cree... Go small as possible for that 1/4 ma of power.
MikeAusC
Enlightened
For high power LEDs, it's well known that as you increase current, the efficiency decreases. Well it turns out that at very low currents, the efficiency also drops off - so there's a point of maximum efficiency.
For the XR-E that peak was at 50mA - about 1/20th of the maximum current - with a sharp dropoff in efficiency below that current.
So for a 20mA LED you could assume it's most efficient around 1mA.
For the XR-E that peak was at 50mA - about 1/20th of the maximum current - with a sharp dropoff in efficiency below that current.
So for a 20mA LED you could assume it's most efficient around 1mA.
