AEDe wrote:

…
Yes It is open. There was a delay at the supplier. But I finally got them today.

F2T6Q2?

F2 voltage bin: 2.8 - 3.0V

T6 chromaticity region: 4000 - 4125K

Q2 flux: 340 - 360 lumens at 1.05A, 85°C.

They're indeed super close to the previous batch.

Cheers

To my advanced organic photon detectors the tint of the LH351D in my close range 30° TIR S2+ flashlight is just about perfect. I wouldn't say it has the slightest hint of any tint (just checked it right now); 0K, maybe a gnat's ass of red but almost unnoticeable.

Cheers

Barkuti wrote:

To my advanced organic photon detectors the tint of the LH351D in my close range 30° TIR S2+ flashlight is just about perfect. I wouldn’t say it has the slightest hint of any tint (just checked it right now); 0K, maybe a gnat’s ass of red but almost unnoticeable.

 

Cheers

I will take some red any day of the week, Green is what I can’t stand. I can’t even use 219C’s anymore due to the green hue. Once you have seen it, you can’t un-see it.

Checked it again against another wall: yes, very very slight rosy tint, more noticeable in high mode (3A) around the “corona”. But it's subtle, as you may understand. If I were to be telling this to some philistine in these matters fellow, he/she would probably say “WTF?”.

However, not all emitters are equal and slight tint differences may be found among them.

Cheers

Hi

I want additional 10× 351B 3000K 90cri

This new batch is T6 bin slightly colder than the first T7 batch. To me that’s getting closer to my perfect preferred temp 4500k.

Texas_Ace wrote:

I will take some red any day of the week, Green is what I can’t stand. I can’t even use 219C’s anymore due to the green hue. Once you have seen it, you can’t un-see it.

Ain’t that da troof…

First got my 47s Quark, grexed about because of the green tint, I was looking, “Nah, doesn’t look ‘green’…”, expecting something like a true green XP-E or something.

Then I see some nice neutral tints, with not a hint of green, got used to them, saw my Quark… ugh.

Spent a small fortune on 2 of them plus a shorty tube, and I haven’t even had a cell in any of them in at least a coupla years.

I played with these ’351s, and I like ‘em… a lot!

moderator007 wrote:

This new batch is T6 bin slightly colder than the first T7 batch. To me that’s getting closer to my perfect preferred temp 4500k.

Yep, me too. 4500k is my ideal as well.

If these are just over 4000k and are rosy, they sound like the next best thing though! My biggest worry was they might be green. Since they appear to be rosy instead, I am now at a point of seeing how much money I can spare lol.

Anyone want to buy my XHP70.2 GT?

In for 10 LH351D 90 cri T6

Nice to see you here Texas Ace.

Time will tell how the tint lottery turns out for Samsung LEDs.

Is the 3000k from the new or the old batch? Very interested in these.

351Bs have always been 3000k in this group buy.

joechina wrote:

…
Time will tell how the tint lottery turns out for Samsung LEDs.

T6 chromaticity coordinate for this new reel. There's no gambling here.

Cheers

What I meant was the reel, what was on the reel? The 3000k or the 4000k ones?

I also don't know if I get this right, but the forward voltage is higher than other LEDs but its more efficient than 219c by about 30%? What does that mean?

Does it mean that it requires more voltage to turn on, yet it uses less energy once it does so?

It means that to achieve a certain forward voltage, it needs less current to do so, and is more efficient if you can push the voltage.

As an example, the Samsung LH351D 70CRI can push 1000 lumens at 3.23V at 2A, meaning an efficiency of 137 lm/W.

The 219C 90CRI can push 605 lumens at 3.03V 2A, meaning only an efficiency of only 100 lm/W.

The 219C has a much lower forward voltage, and yet, it can put out much less light at the same power level.

If I am reading that correctly, the voltage of the battery will affect the duration of the flashlight's usage. As the battery power drops in voltage, it will stop working before a lower fV led would, but it will take longer to get there. Am I stating that correctly?

Lick wrote:

If I am reading that correctly, the voltage of the battery…

There's a direct relationship between battery voltage and state of charge.

In this particular case, a relatively higher Vf led won't stop working before a lower Vf one. For unregulated drivers this just means current reduces, Vf does too… and the torch keeps producing a good deal of light anyway. In case of unregulated (MOSFET and such) drivers actually higher Vf leds result in longer runtimes and higher working efficiency. For regulated drivers it's a bit the other way round, keep in mind that for any given current higher Vf means higher power output, with pretty constant efficiency in this case.

Cheers

Thanks Barkuti! So its better in a FET driver for runtime (and it would mean that less heat would be generated), and its worst in regulated mode.

I guess I will find out how much real life difference it makes. I know one flashlight of mine has a FET, the rest are probably regulated.

is there a risk that the led maybe broken if using DD driver, because the Vf is so low so the current will be high

@ AEDe:
Sorry for asking dumb questions…

I expressed interest here (#40 on your list). I don’t mean to rush anything but I don’t know who’s now in charge for the next step. Are you now waiting for payment from me or do I need to wait for further instructions via PM from you before I send the money? As there were some discussions about Paypal fees (commission, currency exchange, bla bla) some pages before I don’t know if your prices in the first post of this thread are the final prices that just need to be added up. Can I use PayPal for goods and services or are your prices calculated for “friends and family” only? Any hint would be greatly appreciated. Thank you!

mrheosuper wrote:

is there a risk that the led maybe broken if using DD driver, because the Vf is so low so the current will be high

Yes.

Barkuti wrote:

mrheosuper wrote:

is there a risk that the led maybe broken if using DD driver, because the Vf is so low so the current will be high

Yes.

 

No problem with mine.

In my test of the 70cri 351D it did not even make peak lumens until 4.2v. So there should not be any worry about killing it with an FET driver if it is well heat sinked unless the 90cri version is much lower vF.

It does have quite a bit lower VF at 3A compared to the 70CRI 351D.

It’s not at 90CRI 219Cs though, so no problem there.

I have the same basic question as FlashTom.

I want to buy at least 16 of the 3000k ones. Way too good to pass up. Thinking if I want the 4000k ones too.

I just sent payment for

24× 4000k
6× 5000k
24× 3000k

When do you expect the 5000k to arrive?

Payment sent.

payment sent early morning