Dec 13

How to wire 5 Watt Led in Car

I have just obtained two car logo projector units, they mount in the underneath of the car door and reflect a Logo image on the ground when the door is opened.

We tested one unit on a Model Train Controller with an unloaded voltage maximum of 14 volts, the unit is stated as being suitable for 12 to 24 volt systems.

Even below maximum voltage the regulator (for want of a better word), went up in smoke. (Faulty unit?).

The second unit was tested the same way, with 14volts in, the output to the LED was 3.77 volts and the regulator still got very hot, but didn't self destruct (didn't leave it on for a long time, but it was uncomfortable to touch).

I have 5 Watt surface mount LED's and was considering using these with just a resistor in the circuit, as the unit will be tucked away inside the car door, it won't be easily accessible once installed, can I use this with just a dropping resistor, if so, what value would I need, and would a heat sink or enclosure for the resistor be required.

Sorry about the long winded question, I am not real electronics literate but do a fair amount of model trains wiring.

Any assistance/advice will be appreciated.

Ted (Teditor) Freeman.