Build Instructions for Super LED Flashlight

By John Duffy

Ever since Edison made his first light bulb, the majority of artificial lighting has been made using incandescent bulbs. Nowadays, however, we have LEDs, which are significantly more powerful and efficient, and run on low voltage DC. This project is a powerful LED flashlight, which runs at almost 30 watts and 3000 lumens.

• Step 1: First off check to make sure you have all the materials and that they work. The box size is easy to underestimate, so leave a lot more room than you think you’ll need. Also, make sure to wear sunglasses or, even better, welding goggles, when you work with the LEDs, because looking into a lit one up close will most likely damage your eyes.

• Step 2: The first active step is to attach the LEDs to the heatsink. This is one of the most important steps, because the LEDs produce a massive amount of heat in addition to the light, so they will burn out without a proper heatsink. First, clean off the top of the heatsink and the LED heatsinks with alcohol and a cotton ball or q-tip.

Add a generous amount of heatsink paste to the bottom of each LED heatsink, then press it onto the big heatsink and hold it for a few seconds.

After you have put all of them on it, place it on a table facing up and put a heavy object (like the battery) on top of all three and leave it to dry for a few hours.

• Step 3: While you’re waiting for the heatsink paste to dry, build the circuit. Though it is very simple, if it should short, the LEDs, switch, and battery will all fry. The schematic is below. You may think, why a 4A fuse and 3A switch? It’s because the 3A is at 125 volts, so at the 12V of the circuit, it can take more current. Also, the fuse is just to protect against shorts, not necessarily to protect the LEDs.

Wait for the heatsink paste to dry before attaching the LEDs to the circuit. • Step 4: Now comes the moment of truth. Flip the switch and the LEDs should light up.

Bright. Turn it off after 10 seconds and feel the LEDs for excessive heat buildup. They may be warm, but should not be too hot to touch. Note: do not touch the LEDs while they are on, as the light alone can heat up your finger. The LED may feel hot even if the emitter itself is cool. If it did not light up, check the fuse. If it blew, check your circuit for shorts. Otherwise, check it for breaks, and that the battery is charged.

• Step 5: Next, test fit the parts in the enclosure.

The fan should not have anything for at least 1-2 inches behind it, as they may obstruct airflow. If there are no vents, just use a drill or x-acto knife to drill/cut some small holes

behind the fan.

• Make sure the resistors do not have any wires, the battery, or the fan near them as they will get HOT when this is running. Even though they could theoretically take up to 80W, it will heat at 30. Test it all again. The LEDs should not get hotter than they did before, if they do, cut more vents and make sure the resistors are not directly behind the fan.

• Step 6: Select the final component positions, and glue or screw them in place. Close the case, and get ready to fire.

• Step 6-1/2: If you want to, you can add a laser “sidearm” to it. Simply solder the 3.6V battery to the small switch and green laser. Mount the laser and battery in a small box. While wearing laser goggles, test the laser. It will make a very bright, powerful beam that should be visible in a dim room. NEVER point it at anyone, any other living thing, any vehicle, including but not limited to, planes, helicopters, cars, trucks, trains, boats etc. All of these are illegal as the laser will blind the driver instantly. Also, never use the laser without laser safety goggles rated for 532nm. Add a strip of stick-on velcro to the side, and a matching strip on the LED torch. Attach the laser there, pointing forward.

• Step 7: Go light something up!

Before you do so, make sure that no one is looking at the LEDs. They are powerful

enough to blind someone up close. Unless you have welding goggles on, do not look into the LEDs. This is not a toy. It is dangerous if misused, but is harmless if used correctly. Just for comparison, a really bright xenon car headlight tops at about 1000 lumens. This goes to almost 3000.