CREE 4Flow Teardown and Review

[MichaelW]

Yeah for 3850K !

 

[markr6]

By any chance have you tried this one? I'm also looking for a 4000k bulb and this one says it fits the bill.

Thanks! For $10 I may try it. I wish it was higher than 80CRI, but I'm a sucker for trying new LEDs other than 2700K and 5000K.

 

[CoveAxe]

Thanks! For $10 I may try it. I wish it was higher than 80CRI, but I'm a sucker for trying new LEDs other than 2700K and 5000K.

As do I, but finding just 4000k is hard enough. I'll take what i can get for now. i was also thinking of getting these, but right now I don't have any of my CFLs going out, so I'm just playing the waiting game for the time being.

If you do try them, please post about your experience.

 

[Anders Hoveland]

I had a 4000K LED bulb. It was way too bluish for indoor use (except in the garage). I do not think this was actually the color temperature but rather the tint of the light. From what I have seen, LED light seems to have very "bluish" tint at anything higher than 3000K. I know it's not the actual color temperature because I have a 96 CRI 4000K LED emitter and do not notice this problem at all (apparently the tint problem goes away at really high CRI). I think it has to do with the blue spike in the spectrum, if you look at a spectral graph of a 4000K LED.

4000K is not blue. It is a sunny bright, slightly warm, white. But put a 4000K LED bulb in a lamp in your living room and it just looks unnaturally bluish. You might disagree with me, that's fine, just describing my observations. Another factor may be that things look bluer at lower lighting levels at night, the so-called Purkinje effect. Turn on an incandescent bulb in the daytime in a room with a window. You may be surprised at how reddish-orange the light looks.

finding just 4000k is hard enough.

I believe the 3M Advanced cool white LED bulb is 4000K. Also the omnidirectional EcoSmart LED bulbs.

4900K cool white LED works acceptably in the garage (though the tint is not quite my favorite), but I cannot even imagine using 5000K LED bulbs anywhere else in the house. Whoever likes 5000K bulbs for lighting their home is a little weird (imo). 5000K is not the type of thing you put in a table lamp.

 

[idleprocess]

I believe the 3M Advanced cool white LED bulb is 4000K. Also the omnidirectional EcoSmart LED bulbs.

3M Advanced is expensive, heavy, inefficient, and my sample lost a quadrant of LED's after perhaps 1000 hours of operation in an open fixture.

4900K cool white LED works acceptably in the garage (though the tint is not quite my favorite), but I cannot even imagine using 5000K LED bulbs anywhere else in the house. Whoever likes 5000K bulbs for lighting their home is a little weird (imo). 5000K is not the type of thing you put in a table lamp.

Table lamp, bedroom, dining room ... probably not. Hallway, utility room, kitchen, bathroom, closet, work space - sure. Anywhere you need focus or some attention to colors you're probably better off with something closer to 4000K - and 5000 is about as good as it gets from mass-market.

 

[idleprocess]

I picked up a pair of these today (1x 2700K and 1x5000k) from Home Depot. I dislike both of those color temps (it's like the options are candle light or mercury-vapor) so my plan was to swap half of the emitters between the two bulbs using my hot air station. When I got home and watched Electron's review, I realized Cree had already done all the hard work for me. Once out of the bulb shell, the two PCB-planes slide apart with a little wiggling. The electrical connections between the two are those same spring contacts used in the bulb base that Electron detailed in his video... No soldering or hot air required. Even the shell halves are lightly glued.

I've done something similar to this - using alternating cool/warm bulbs to try to shift the color temperature. I've got two fixtures 1:1 2700/5000 for ~3850K and another that's 2:1 ~3467K. Color mixing is decent on the vanity-bar style fixtures, not so great on the overhead ceiling fan I tried it on.

 

[bobski]

I couldn't figure out a good way to separate the bulb halves. How'd you do that? They're not totally glues together?

Exactly. The bulbs I bought were only glued near the top and lightly half way down one side. Once the base is off, it's pretty easy to crack the glue joints and pry them open from the bottom up.

 

[brickbat]

Brilliant - mine popped apart in less than 5 minutes... Now I've got to go pick up a 5000K for the switch-a-roo...

 

[martinaee]

Wait... so that works easily? If so that's actually a really cool hack I'd like. Mixing 2700k and 5000k bulbs is what I'm doing in my apartment living room currently. 2 different temp bulbs in 2 identical lamps.

 

[SemiMan]

I had a 4000K LED bulb. It was way too bluish for indoor use (except in the garage). I do not think this was actually the color temperature but rather the tint of the light. From what I have seen, LED light seems to have very "bluish" tint at anything higher than 3000K. I know it's not the actual color temperature because I have a 96 CRI 4000K LED emitter and do not notice this problem at all (apparently the tint problem goes away at really high CRI). I think it has to do with the blue spike in the spectrum, if you look at a spectral graph of a 4000K LED.

4000K is not blue. It is a sunny bright, slightly warm, white. But put a 4000K LED bulb in a lamp in your living room and it just looks unnaturally bluish. You might disagree with me, that's fine, just describing my observations. Another factor may be that things look bluer at lower lighting levels at night, the so-called Purkinje effect. Turn on an incandescent bulb in the daytime in a room with a window. You may be surprised at how reddish-orange the light looks.

I don't agree with your observations, I just disagree with you not being completely clear in how those observations were made and what it means. I also disagree with reading 1/2 or 1/4 of a Wikipedia article and then posting things here as fact when you don't really understand them, i.e. the Purkinje effect which applied to lighting occurs at mesopic lighting levels, which are not lighting levels we typically use in a home.

I sit under 4000K, 80(min) CRI LEDs all the time. Nope, no blue tint. Of course, I am adapted to this light so why would I see any blue tint when they sit fairly close to the blackbody. If you are seeing blue tint on a 4000K bulb, either your bulb isn't really 4000K or more likely, it is just one bulb in a light environment that is predominantly a lower CCT. Light a room exclusively with 4000K bulbs and sit in their for 30+ minutes then tell me it has a blue tint.

The fact that an incandescent bulb looks reddish-orange in the prescience of bright sunlight has nothing to do with the Purkinje effect. That is basic white balancing of the visual system. When you have adapted to 5000-6000K, then 2700K looks reddish-orange ..... similar to how if you adapt to bright 2700K, then introduce a 4000K bulb, it is going to look "blueish" .....

CRI -- ONLY matters when you illuminate something, not when you look at it directly by the way and that something you illuminate better not be white or again, you are just looking at the bulb directly somewhat.


Semiman


p.s. but what the heck does this have to do with 4Flow ... no need to hijack every thread to try to make it look like you are an expert on lighting and color ... since obviously ....

 

[James1095]

That's a clever idea mixing the boards between bulbs of two color temps, I might have to try that. In general though I'm pretty happy with 2700k for interior lighting and 5000k for utility lighting. I suspect the actual market for other color temperatures is rather limited amongst "normal" people who don't spend much time thinking about light bulbs. The big goal at the moment is to provide an efficient alternative to all the folks still clinging to incandescent so it's only natural that the bulk of the LED bulbs on the market are trying to mimic the old fashioned 2700K A19 filament bulb.

 

[Anders Hoveland]

the bulk of the LED bulbs on the market are trying to mimic the old fashioned 2700K A19 filament bulb.

Although it has become a commonly repeated fact often thrown around that regular incandescent bulbs are 2700K, the truth is more complicated. The 1650 lumen (shorter-life) 100 Watt standard American bulbs, for example, were around 2865K. That is actually a substantial difference from 2700K.

 

[bobski]

For those playing with the bulbs, a note on polarity between the main and daughter boards: each board has a plus-in-a-circle registration mark on it - they should both be in the same quadrant. If you get it backwards the bulb just won't light... No magic smoke.

 

[Anders Hoveland]

Brilliant - mine popped apart in less than 5 minutes... Now I've got to go pick up a 5000K for the switch-a-roo...

You might want to add just 1 green emitter in there. When you combine a low color temperature and a high color temperature, the resulting mixed light can be a little magenta-tinted compared to what the color coordinates should be at that mid correlated color temperature.

 

[brickbat]

The 2700/5000 4FLOW switch-a-roo worked. I had a little more trouble getting the plastic bulb apart on the 2nd lamp, but no big deal. A couple drops of super-glue on re-assembly, and all's good.

So, now I've got two ~4000K lamps. To me, their tint seems very close in CCT to a Sylvania 840 (4000K) T8 fluorescent lamp. The frosted plastic globe does a decent job of mixing the two colors.

I didn't notice the polarity dots - guess I got lucky, as they both worked the 1st time.

 

[SemiMan]

Or don't add the green and get what experiments show is the preferred location of the white point wrt how people like light to look, not what replicates the "unnatural" and non existent blackbody locus light source

 

[brickbat]

Yeah, I'm super-special and sensitive - personally I find that light with too much cyan or green in it makes me feverish, grouchy, constipated, gives me a hives and a headache, and causes my ears to bleed.

 

[idleprocess]

Although it has become a commonly repeated fact often thrown around that regular incandescent bulbs are 2700K, the truth is more complicated. The 1650 lumen (shorter-life) 100 Watt standard American bulbs, for example, were around 2865K. That is actually a substantial difference from 2700K.

Clearly, this explains the popularity of dimmers on incandescent lamps - which pushes the CCT well below 2700K - under-volted "classic" incandescent bulbs which are also very low CCT, and 2700K LED bulbs that respond to dimming by reducing their CCT.

 

[James1095]

For the vast majority of our existence, the only artificial light and warmth humans have had is fire. Firelight still triggers a warm cozy feeling in most people so I suspect that's why there is a general preference for low color temperature lighting in homes. It makes food look more appetizing too IMO.

 

[crazyk4952]

I just picked up a couple of the 4Flow bulbs for $5 each at my local HD without any utility rebates.

The price online still shows as $8, and I am not sure why they were cheaper in store.

I put them in an enclosed fixture to see how well they do.