GB 351D closed.

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


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?

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!

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.

Sorry guys I was very busy during last two weeks. I have enough LEDs for all who now in the list.
So if you dont have a questions and request, you could not wait my PM and pay to my PP address andreyderbishev@yandex.ru according price in the top of first message
351B 3000K 90cri are available. Price
1-49 0.55$/pcs
>50 0.50$/pcs (including PP fee)
351D 4000K 90cri will be available in a week.
Price
1-19. 1.7$/pcs
20-49 1.6$/pcs
>49 1.5$/pcs
351D 5000K 70cri on order
Price
1-19. 1.7$/pcs
20-49 1.6$/pcs
>49 1.5$/pcs
Shipping 5$
All prices include PP fee.

You should use “for goods and servises”
And make sure that you send $ (or euro according ECB rate) not RUB
In comment in PP please write your BLF nickname.

I just sent payment for

24x 4000k
6x 5000k
24x 3000k

When do you expect the 5000k to arrive?

Payment sent.

payment sent early morning

They are allready in stock.