[chbot] High Power LEDs

[Volker Kuhlmann]

On Thu 03 Oct 2013 13:38:58 NZDT +1300, Mark Atherton wrote:

> 27V * 0.35A may be 9.45W

D'oh - I plonked 0.25A in... So the numbers stack up.

> My comparison between the 75W in my office and the 10W LEDs was
> subjective. Wikipedia indicates that the 75W lamp may be in the
> order of 1200lm, but seemed close to the LED output. So LED was
> high, lamp was low or my eyes are out of cal :)

I've always wanted some good data on lumen output of incandescant bulbs,
but it's tricky. Best might be

http://ec.europa.eu/energy/lumen/overview/howtochoose/packaging/packaging_en.htm

Which has a lot of good info. 100W -> 1300 - 1530 lm.

If you got your Wikipedia numbers from
http://en.wikipedia.org/wiki/Incandescent_light_bulb#Electrical_characteristics
then that table must be seriously dud:

100W -> 1700 lm 120V lamp, 1160 lm 230 V lamp.

Well I call that, uhm, interesting. True it's possible to make
differently bright bulbs for 100W, but not by changing voltage. (I can
only come up with filament length as variable effecting lumen output.
100W stays 100W no matter material, resistance or voltage.)

> Can't find any real data on the DC-LE14177, but the price it right
> and the application volume too low to be an issue (?)

One of the reasons for wanting a datasheet is to be able to judge its
likely colour. It takes time to test, no matter the purchase price. I
dislike all the drop-in bulbs on the market I've seen so far as being
plain green. Yuck.

> http://www.superlight.co.nz/ may know about approved LED PSUs, bet
> they are 4x the Chinese price.

Maybe, but do you really buy $10 mains voltage stuff of unknown origin?
An optocoupler or capacitor of unknown vantage and unidentifiable
quality between you and the grim reaper? An extra $30 sounds cheap to
me.

Apart from that, where do you buy superlight stuff from? I asked them
earlier this year and got nowhere. Or the answer was Rexel, Ideal etc -
I had it with those. Easier and much faster to buy from Element14, and
more competence for the same price.

Volker

-- 
Volker Kuhlmann
http://volker.dnsalias.net/	Please do not CC list postings to me.