Author Topic: LEDs are sweet  (Read 6777 times)

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Offline beaky

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Re: LEDs are sweet
« Reply #15 on: November 29, 2009, 09:43:59 AM »
I love neon, and allways thought it was very power hungry.

And there my friend is the myth - i have heard stories from customers told to them by LED salesmen that neon runs so hot that the aircon in the shopping centres is on full blast.. LED will aleviate this.
heres the facts..

LED requires 12v or 24V DC supply dependant on the number of LED in series. LED MUST have a steady current or you will kill it.... LED is supposed to last 100.000hrs continuous use... in the field 4 - 6 months is typical.

LEd is available with constant current supply - it is very expensive and still not reliable.

The most efficient power supply that i have in my shop for LED draws 1.4A @ 240V and supplies 180W @12V ( 15A).. this will load at 80% and will therefore give a linear length of white LED of 13M tops.

With an iron core transformer - once again loaded to 80% i can supply 13M of white neon with a current input of 1.23A @ 240v.. but to add the light output of neon is 1.5 of that of LED. Already a saving of  40.8W but with 1.5 times the punch

Now if i run my neon with an electronic power supply the same technology that runs LED then for 1.4A i can run a whopping 66M of neon.

neon has been around for over 100 years simply because it has the most punch for dollar - always has been.

Difference is that LED is 12V @ 15A - input 1,4A

Neon is 10,000V @ 30mA input 1.23A Iron core..... 0.4A electronic


 Neon High voltage - low current

LED Low voltage - high current.

Oh and just to add neon will outlast ANY LED.. i always give 2 years unconditional guarantee against failure.. last time i spoke to my LED supplier who supplies GE type ( considered the best with CREE chip) his returns after 5 years still remain at around 60%... mine after 5 years are ZERO and i mean ZERO!
I have found if you run leds on a long run of cable( i.e. your power supply is 10 or 15 meteres away from leds) then you have problems with inductance or power serges, especialy if the cable runs along metal. a way to get around this is 1st use a tranzorb and second use a switch mode regulated power supply that brings the current up slowly,(when i say slowly it means still fast enough that the leds look like they are instantly on but if you look at it on a crow then you can see that it rises in a linier fashon).
when i was designing led fittings and power supplies to suit i found a switch mode voltage regulator that did just this and after we started using these regulators and tranzorbs in our control gear and fitting the amount of warranty returns dropped from 30% down to 1%.
i still have the schematic for this power supply.
Another advantage with the said power supply is it would supply 5.5 amps continuously and the output could be shorted indefinitely with out the power supply overheating, also when the short or excess load was removed the power supply would work again without pressing a reset button.
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