Wow, those look nice! Are there any special requirements for running this 5mm LED at the higher end of its permissible amperage range?
To run (any LEDs on the menu) at high current, it’s preferable to:
- Drive the LED in constant-current mode: As the LED heats up, it will take more current in a feedback loop until it either
a) finds a thermal equilibrium or
b) enters the thermal runaway and die.
Constant current driver will ensure that the current will stay at a managable level, or at least keep the deterioration rate at the constant level (as opposed to rapidly)
- You may need to enhance the heat dissipation on the cathode lead: The only way thru-hole LEDs can realistically dissipate heat is by thermal conduction through the cathode lead, where it connects to the base that the die is attached to. Based on my educated guesses, you could try:
a) If the board has large ground plane where LEDs are to be soldered on, you should shorten the legs as much as possible to minimize the thermal resistance to the ground plane.
b) If the board doesn’t have the ground plane, you may need to keep the legs as long as possible to maximize the surface area instead.
c) Put the airflow on the back of the board to cool the ground plane.
Well, well...
I guess i need another package. Let's try those bada55 newcomers.
RWN05-45K-B (4500k 5mm) Tests by Djozz (20 mA)
The specs on both of those new emitters look great, especially that higher powered 3200k! Although the 3400K has been reported to perform well in the Nitecore Tube, this model should be slightly brighter and provide more assurance of a long life.
I wonder if Nitecore would be open to buying some to do a special edition Tube CRI, or Klarus on the similar Mi2…
Payment sent for 3200!
Thx.
The US store Costco currently has 8-packs of “Life Gear” brand colored LED glow sticks for something like $20. They’re a bit larger than it seems like they need to be, but otherwise seem like a good value.
They are a bit unusual in that they have a flashlight on the opposite end of the glow stick. As expected, it’s a probably 6500+ K cool white, so I immediately started replacing them with warmer, high CRI LED’s. My kids are definitely enjoying them.
Here’s three of them with the flashlight end replaced with a rngwn 2300K, an rngwn 3400K, and a Yuji 5600K. There is a cheap reflector around the LED that causes a slight lopsided hotspot, but overall, the replacement LED’s are a huge improvement.
It took me a few minutes to figure out how to get them open. A screw locks the diffuser in place, so children won’t accidentally access the button cell batteries. The lens on the flashlight end seems to be glued in place, but it turns out a solid tap of the head against a hard surface will cause the entire light assembly to drop out the other end:
Blue spikes are high
These are normal blue 450nm based white leds so they have their 450nm spike which is needed as part of the visible spectrum to form the CCT/CRI, nothing extraordinary here compared to other leds, that is simply how they work. A few manufacturers recently came with new types of leds with 420nm base leds or with double dies, reducing the blue peak and filling in the cyan gap, but those are far from mainstream yet and none of the regular leds used by BLF have that.
I read about new Leds,and 420nm is near UV-A.
Marketing from bad to worse.
So what? It is the base led, the phosfor converts almost all of it to make the rest of the spectrum. Look at the spectrum of these leds and you see that the remaining small 420nm peak is hardly higher than the 420nm level of any incandescent or day light of the same colour temperature. Which implies that you are afraid of most natural light sources too (excluding maybe camp fire light) which is not very practical in life unless you are dedicated to spend your life inside under a edison bulb at 2500K.
I wish you will test one day these 420NM Leds
from unknown brand,so we’ll know if they’re safe.
Afraid? I already take enough natural daylight,don’t need more UV-A on night
*UVA is the least harmful type of UV
*420nm is not even UVA
*the 420nm region is a small part of these led’s spectra
*people who are frightened of blue peaks should have a look at light levels before getting afraid of a certain light source.
Quick calculation: the 5mm leds at discussion here at 20mA produce about 50 lux at 0.5M distance, which is shining a flashlight at yourself at an arm’s length. Let us assume that it is just as harmful as daylight (which is not true, it is much less harmful because it contains 0% UV, but ok) and you expose yourself directly to this flashlight for two scorching hours 
That is equivalent to an exposure of about 3 seconds of sunlight (130 klux).
Even worse than the amount of blue light is any source of lights that switch on suddenly in front of the eyes at night,
Like motion sensor spotlight 
I guess I’m a bit insensitive 
I hate when they are brighter than my flashlight 
. At least, sensor lights should slowly (1 s) ramp up so you’ll have a chance to focus elsewhere.
You’re blessed.
I liked when swiched on ,CFL bulb increased bright gradually was pleasant near bed
but they took too long time to arrive at max.
Does there are a sort of fast auto dimmer (1-2sec.) on modern Led bulbs
Or similar to put on wall box for inca. lights?
Never seen a bulb that does this. I’d buy it if it has as additionaly three mode UI.
If you find an external box, let us know.
There is a thread dedicated to the blue light topic that would be a better place for a detailed continuation of this tangent.
As a couple brief comments, though: I second djozz’s observation that the spike shown is very typical. For example, in the top part of image here is a spectrum of a 4500K Nichia 219B (from Maukka’s Fireflies ROT66 review) of the same color temperature. It’s very similar in the location and relative scale of the peaks and valleys:
https://i.imgur.com/g2HKhcQ.png
I’ll leave off my other thoughts on the topic, and simply note that based on the research I’ve read: if in doubt, there’s certainly no harm in erring towards lower light levels as the first priority, lower color temperatures as the next priority, and high CRI as a final priority to reduce blue light exposure. However, I have not seen research that indicates the typical narrow spike is worse than the more spectrally distributed but similar total energy of blue emission in an idealized black body.
Got the 32K-CEX today. What a nice surprise they are very rosy. Love it.
Left: C01, right: Tube.
Thus far, closest to the Yuji. Tried all LEDs in the pack, tints do not vary much, which is also very good.