LED's from Besthongkong

[Velcro]

LED\'s from Besthongkong

I'm looking for blue and red 5mm LED's with a 20° or wider viewing angle (preferably 30°). I checked Besthongkong and noticed they've got a batch of new blue LED's that are rated 6000-8000mcd max. with a 20° viewing angle. The model # is BUBC333BA09 and they are $20 for 100 pcs. This seems like a great deal considering that their 4000mcd LED's sell for $16 @ 100pcs. They also have red LED's that are rated 11000mcd max. with a wider then 20° viewing angle (so they claim). Their model # is BURLC333W20BA10 and they cost $23.70 for 100 pcs.

This is a beamshot of one vs. one of the 'regular' LED's. Do I need to tell which is which? /ubbthreads/images/graemlins/cool.gif

Has anyone bought those LED's from them? Whats the beam quality of the blue ones like? What about consistency and wavelength? Also, what are your experiences with Besthongkong? What about delivery time? I know there are some posts about them but I can't seem to find them right now. Many thanks in advance!

 

[Robban]

Re: LED\'s from Besthongkong

I've read through the forums on their site (Ken is the owner). And judging by soem of the posts it seems like you either have great service or no service at all. Ken is also very slow on replying to posts (and e-mails judging by posts on the forum). I have no personal experience with besthongkong though.

(not trying to diss them, just telling you what I've read)

 

[ViReN]

Re: LED\'s from Besthongkong

try chi-wings LED's....@ebay

you wont be dissappointed, they are bright, cheaper than what you have mentioned...

-ViReN

 

[Velcro]

Re: LED\'s from Besthongkong

I'm a bit confused. I checked Chi-Wing and their specs seem a little low. Brightest red and blue LED's I could find where 6000mcd max. with a 15° angle. Seems like all their LED's are 15°? I've seen much better specs here and there. Besthongkong has blue 8000mcd max. w/ 20°, and red 8000/11000mcd max. w/ 20°. Price is similar to Chi-Wing too. I've also seen a blue 5mm rated 8000mcd w/ 30° angle on a Dutch website. And a red (Kingbright) at 11000mcd (typ.) with 30° on a German site. But those are 85EUR and 69EUR for 100pcs respectively. /ubbthreads/images/graemlins/ooo.gif Hebeilt has a blue rated 11000mcd with ±20° angle, but again not cheap at $0.56 per LED or $110 for 250 pcs. Anyway, perhaps Chi-Wing has had some low spec shipments or something? I recall a lot of CPF members buying LED's from them with significantly better specs.

 

[jtr1962]

Re: LED\'s from Besthongkong

A lot of Chi-Wing's LEDs are underrated. Most of the ones I've gotten seem to have beam angles of 20° to 25° rather than the 15° claimed. Also, the mcd figures are often higher. Craig tested their 4000 mcd ocean green LED at over 10000 mcd (and it had a wider beam angle than claimed as well).

As for some of the other specs you mentioned, the 8000 mcd blue with 30° beam angle is not possible @20 mA given the current state of the technology. This is an output of 1.73 lumens, or 27 lm/W with a typical Vf of 3.2V. For a 470 nm blue LED 27 lm/W would mean it is roughly 39% efficient at converting electricity to light. The highest I've heard so far is 42% for Cree's 27mW blue chip (available only in samples). The production 24mW chip is 37.5% efficient, but once this is incorporated into a package the net efficiency might be 33% at most. For a blue LED at best you'll get 6500 mcd with a 30° beam angle or 15000 mcd with a 20° beam angle. Both figures assume 33% net efficiency, and that 100% of the LED output goes into the beam. Since light always spills out the back of the package, the rating will be less-probably 6000 mcd and 12000 mcd, respectively. The other specs certainly seem believeable but the 11000mcd 30° Kingbright also pushes my credibility. I think this came out to over 40% efficiency when I calculated it based on the wavelength. I'm not aware of any production reds with efficiencies that high.

All told, ChiWing has some good LEDs and some mediocre ones. Their ambers and oranges generally are a bit dim compared to the best you can buy. You can also probably buy brighter reds and blues, although by a lesser margin. Their cyan (ocean green) seem very good when you go by the actual output and not the specs. The true greens seem pretty lousy, but they might again be underrated. I've never tried them. BestHongKong's 12000 mcd true greens are very bright with a >20° beam angle so they might be better. All of Chi-Wing's SMD LEDs don't seem particularly exciting either going by specs. I tend to think that Chi-Wing doesn't update their specs that often, except for their whites, as they get brighter chips. And their beam angle ratings are useless. I especially hate beam angles speced as ±10°. Is this a 10° beam or a 20° beam? Their whites do seem to be competitive though. I believe this is where they concentrate most of their efforts. Most of the rest of their products seem like an afterthought.