Flood lights sometimes tend to stop working over time eventhough nowadays they use LED's. This could be due many reasons such as overheating or a fault in the LED driver or a fault in the manufacturing process. Most of us end up throwing away a product if the warranty has expired.

In this instructable I will be showing you how I made a dimmable LED Flood Light that can even be powered from your car or a couple of batteries by using one of my old 20 Watt Flood Light which did not work.

List of necessary items:

Old 20 Watt Flood Light Casing - 1
New 20 Watt LED – 1
Heat Sink Compound - 1
XL6009 Boost Converter - 1
10K Potentiometer – 1
Washer (with the centre hole big enough to fit the potentiometer knob)
10K Resistor – 2
Bolts and Spacers
12 Volt Female Connector – 2
12 Volt Male Connectors – 2 (Optional)
Male Car Cigarette Lighter Connector – 1
Wires

Step 1: Replacing the LED

After disassembling the flood light, I removed the LED driver, which will not be of any use for this project. I also removed the glue which held the LED driver in place. I then removed the waterproof seal for the wire using an adjustable wrench and a plier.

I desoldered the connections to the LED and tried to power it ON using external power at 30 volts (which is the forward voltage of a typical 20 Watt LED). But it did not turn ON. The LED was dead.

I removed the screws holding it in place, pulled out the LED and wiped off the old heatsink compound. I will replace the LED with a new one, but before I secure it in place, I will add some fresh heatsink compound.

Thereafter I aligned the LED in place, and secured it with its screws.

Step 2: Wiring the Boost Converter

Now its time for the boost converter. I used an XL6009 Boost Converter for this project since it can handle upto 3 to 4Amps.

When you are trying to decide if a specific boost converter will suit your project, you need to calculate it by taking into consideration the input voltage, not the output voltage. In this case, the LED uses 20 Watts, and if I input 12 volts to the boost converter, 20 Watts divided by 12 Volts is around 1.7 amps, which is within the range the boost converter can handle.

Steps:

I desoldered the small potentiometer in the boost converter. Don’t throw this away, we need to use this as a trimmer potentiometer.
I used a 10K potentiometer to which I attached a 10K resistor to its middle Pin.
I then connected a wire to the resistor and another wire to the Pin on the left side of the potentiometer.
I soldered in another 10K Resistor to the middle pin of the potentiometer we removed from the boost converter (the small blue rectangular pot).
I inserted heatshrink tube before I solder, so that I can insulate the connections.
I connected a wire to the resistor of the small potentiometer and another wire to the Pin under the golden knob.
I connected those wires to the left and right most contact points to where the small potentiometer was attached to, of the boost converter.

Step 3: Adjusting the Boost Converter Output

You will need to check on the forward voltage of your LED before applying power. Going over voltage can burn out the LED. Typical 20 Watt LED's usually have a forward voltage of 30 Volts.

I connected 12 volts to the input of the boost converter and connected my voltmeter to the output.

I then turned the dimmer potentiometer (the big one) to the MAX (all the way to the right).

Afterwards I turned the trimmer potentiometer counter clockwise (you will need to turn it alot) to get a reading of 30 volts in the voltmeter, since the forward voltage of the LED I am using is 30 Volts.

Now by turning the Dimmer potentiometer, we can adjust the output voltage from the boost converter, and it maxes out at 30 Volts, thereby keeping the voltage within the range of the LED.

Step 4: Connecting Everything Together

I soldered in two wires to the terminals of the LED and mounted the boost converter to the casing with spacers and bolts.

I thereafter connected the wires from the LED to the output of the boost converter, making sure of the polarity.

I soldered in two wires to a 12 volt female connector. Make sure of the polarity when connecting the wires, if you connect it the wrong way, you could damage the boost converter. Afterwards I connected those wires to the Input of the Boost Converter and mounted the 12 Volt Female connector to the casing where I previously drilled a hole to fit the connector.

I mounted the dimmer potentiometer to the case using a washer since the hole which was previously there to pass the wire for the earlier LED Driver was too big.

I screwed everything back in place, and added a knob to the dimmer potentiometer.

Step 5: Plugging the Flood Light to a Vehicle

I connected a 12 volt female connector to the back of a male car cigarette lighter connector so that I can provide power to the Flood Light from the Car. This is optional. You could either connect some wires directly to the cigarette lighter connector as well.

I also used heatshrink tube to insulate the parts.

Make sure of the polarity when connecting the 12 volt female connector.

Using flux will help solder in the wires much more easily.

I connected a wire with both ends having a male 12 volt connector to the previously modified cigarette lighter connector.

I thereafter plugged in the cigarette lighter connector to the Car. After connecting the other end to the flood light, it lights up.

I can increase the brightness by turning the potentiometer.

I hope you found this instructable useful. If you have any issues, feel free to comment below. If you would like to find more of our content, feel free to subscribe to us :)