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On the topic of leds maybe one of you more electronicly inclined gents can help me

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Old 06-04-2008, 04:37 AM
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Default On the topic of leds maybe one of you more electronicly inclined gents can help me

so i changed all my rear bulbs to super wide angle led lights so they would be brighter (with less heat) to illuminate my tinted tail lights. The problem is that now i get the brake light indicator on my dash because the leds do not draw as much voltage or current as stock bulbs do. I know that the way to fix this is to add load equalizers to the lines, but i do not know how to select the right load equalizer. Load equalizers come in several sizes ranging from 25 watt 15-25 ohm up to 50 watt 6 ohm or 3 ohm. I think i need the 25 watt 15 to 25 ohm equalizers but i really am not sure..any help is appricated.

for refrence here is a link to several load equalizers.

as always, thanks,

-BQ<ul><li><a href="http://autolumination.com/equalizers.htm">load equalizers</a></li></ul>
Old 06-04-2008, 05:01 AM
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Default What is the difference in power draw between the LED and the stock bulb?

If the LED is 5W and the stock bulb is 25W, then you need to "equalize" 20 watts. Mr. Ohm tells us that P=IV (Where P=power in watts)and V=IR --&gt; P=I^2R, so in order to draw 20 watts from a 12 volt system (really closer to 13.5 volts):

20W = I* 13.5V, so I = 1.48 A
Then 20W = (1.48)^2 *R so R= 9.13 ohms.

For this system you would need a 9 ohm 20 W resistor- any higher wattage rating would also work.
Old 06-04-2008, 05:05 AM
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Ow! Too early for Ohm's Law and math equations. My brain hurts! ;-)
Old 06-04-2008, 05:17 AM
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Default Re: What is the difference in power draw between the LED and the stock bulb?

way to remember college physics.....per my usual mo i will just go overkill and get the bigger ones per ur suggestion. Thanks for the help!
Old 06-04-2008, 06:20 AM
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Your load equalizers will get warm/hot so be careful where you mount them.
Old 06-04-2008, 07:56 AM
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Default Very true- best to use thermally conductive epoxy and glue them to a metal surface that will....

conduct the heat away and dissipate it.
Old 06-04-2008, 09:07 AM
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Default Summary: You lose the inherent efficiency of the LEDs...

due to the need to fool the lamp detection circuit. However the difference in mileage (due to the loading on the alternator) would be very small. Too bad there's not a way to calibrate the lamp detection threshold with VAG-COM.
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