<VV> Re: LED taillights
JVHRoberts at aol.com
JVHRoberts at aol.com
Mon Jan 30 17:50:55 EST 2006
Yeah, I know about the diode. My mistake. Sorry about that.. <G>
The numbers you're quoting are for there Luxeon ls. The parts I listed are
Luxeon llls. The Luxeon IIIs are rated at full power at 1400 mA. You won't cook
anything. But the resistors will get quite warm, so, make sure they aren't
against anything that can get melted.
You need a fair bit of difference in brightness to be noticeable from tail
to stop function. With my circuit, you should have about a 6:1 difference,
which is what commercial LED taillights run. 60 ohms on tail, 10 ohms on break.
That works out to about 1100 mA on brake, and something just under 200mA on
tail.
The calculations are correct for Luxeon IIIs.
Wait a few months, and the new Luxeon K2s will be out. These are nearly 8
watts, and are over 4 times as bright as the Luxeon IIIs!! But are harder to
mount, etc... <G>
In a message dated 1/30/2006 3:52:09 P.M. Eastern Standard Time,
Bucketboss at aol.com writes:
>>>SNIP
There really should be another diode on the tail light side to prevent
back driving the light circuit.
>>>>SNIP
...what he said... and the LED as well as that poor 10 ohm, 10 watt
resistor
is going to take a beating when the brakes are on @ 1.1 amp
draw.....momentarily.
Those are some wicked looking LEDs (on the website). Check me if I'm wrong,
but from what I gather, the designed MAXIMUM current for the LXHL-LD3C
star
is 350ma. nominal and 385ma. peak.
With the brakes on, that 1.1 AMPs would/should cook the resistor and LED.
Shouldn't it be say 33 ohms minimum STOP/TURN (brightest) to ground and say
another 33 ohms to the tail circuit. You still need a resistor wattage (for
the
grounded one) in the heating element range.
Dave Fierek
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