Replacement of the stock cooling fans with an external air blower to give improved cooling for longer led life.
The leds I used are the newsun h4 headlight replacement from Amazon
These lamps are legal in my country since the color temperature is 5000k and I adjusted the headlamps to put the light on the road and not in other drivers' eyes.
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Step 1: 12 Volt Duct Blower Fan
A high cfm duct fan needed to draw external air. I installed mines behind the front license plate to provide protection and easy fresh air supply.
Note the black silicone I applied to seal off the discharge of the fan so all the air goes into the hoses. You can use any color. Also I placed silicone to seal the top where the circuit board is for the fan.
Step 2: Garden Hoses for Cooling Air
I used 3/4 inch hoses to channel the air from the fan to into the engine bay. Securing of the hoses is important as there cannot be any kinks or movement of the hoses to hot/moving components in the engine bay.
Step 3: Hose to Led Heatsink
The cree h4 led lamp has a star shaped aluminum heatsink. A 1 inch garden hose slides over this to provide a secure fit. Cool external air over the heatsinks will help the led h4 to last longer.
In the pic of the leds you can see the small cooling fans. These simply cannot cool a high power led using hot air within an engine bay. Unscrew them and slip on the 1 inch hose to get cool air directly over the heatsink.
Step 4: Monitoring of the Duct Fan
I needed to remotely monitor the fan while driving. Using a drok voltmeter ammeter from Amazon. I installed mines in the middle console. The current for my fan is 0.24amps. If it rises to about 0.30amps then that's a stalled fan condition. If it's zero amps then no power to the fan.
Update July 2016:
I have removed this cooling system and left the heatsinks passively cooled. The LEDs perform the same as before and this shows how well engineered they are. Also, since my engine bay was modified years ago, there is lots of free space for hot air to easily exit.