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Convert Your Mini Maglite to LED

Into the Woods with a LED Mini Maglite

Jameco Builds logo By Jack Arcade

Description: Mini Maglite LED Conversion Kit
Assembly Time: 2 hours
Skill Level: Intermediate

Mini Maglite Flashlights are always useful especially if you like to camp like me. Out in the woods, when you are away from your iPhone flashlight, a Mini Maglite comes in real handy. Now, what if you hate its yellow color and carrying extra batteries? What if you want a white color for your flashlight and a longer battery life? Sound exciting? Let's make one.

Required Tools:
Mini Maglite Flashlight
Fine Tip Soldering Iron
Solder Paste or Liquid Flux
PCB Holder
Magnifying Glass
Tapered Reamer or #12 (4.8mm) Drill Bit and Drill Motor

The kit includes:
Part Description Manufacturer Part Number
3mm Nylon Spacer R30-6700394
10-Foot 24AWG Solid Bus Bar Wire 3819-10FT
0805 0.22µF SMT Capacitor GRM219R71E224KA01D
0805 1µF Multilayer Capacitor 0805ZC105KAT2A
Schottky Diode SOD-523F Package BAT54XV2
LED Driver IC, TSOT23-5 Package CAT4137TD-GT3
22µH Inductor, 1210 Package LQH32MN220J23L
White LED, T1.75 Package C535A-WJN-CU0V0231
12Ω Resistor, 0805 Package RC0805FR-0712RL
Printed Circuit Board

Building the Kit

My experience building the kit will help guide you as you build the kit. Though this kit may look small and quick to finish, it requires SMT soldering skills and quite a bit of patience to build it.

If you have not done surface mount soldering before, don't jump into building this kit. Practice surface mount soldering first, then try this kit. It took me a bit longer to solder as I didn't use all the proper equipment for SMT soldering.

To get started, dismantle the head of the Mini Maglite and pull off the bulb by applying some force as it might be stiffly mounted.

Top View of Completed TrioriYour Mini Maglite should look like the image on the right.


Make sure you have all the parts of the kit with you as well as additional tools.

Mini Maglite LED Conversion Kit Parts Mini Maglite LED Conversion Parts (click to enlarge)

Once you have all the parts with you, figure out the capacitance of C1 and C2 using a multimeter. When distinguishing parts, keep in mind the resistor, inductor and IC are very distinct. Figuring out the terminals of the diode could be challenging though. You could either use the multimeter to determine the terminals of the diode or simply use a magnifying glass – just find the faint silver line on the diode, which should be the cathode, or the negative terminal.


Use solder paste, solder flux and a soldering iron with a bevel tip to solder the parts perfectly. As the PCB is very small, you will need delicate hands and some patience while soldering.

Top View and Bottom View of LEDTop View and Bottom View of LED (click to enlarge)

Soldering the LED could be challenging as you need to keep some distance (0.1") between the LED base and the top surface of the PCB. Use a thin cardboard as mentioned in the instructions to do it. The PCB doesn't show the terminals of the LED but the instructions do. The cathode (shorter lead) of the LED is closer to the J1 on the PCB, thus install and solder in that fashion.


After you solder the 24-gauge wires, make sure the total length of your assembled kit matches with that of the original Mini Maglite LED. The length needs to match the original length so as to properly close the focus control and lens cap. Make sure to use the spacer so the inductor doesn't get damaged while you adjust the focus.

Make sure everything is properly aligned and that you drill an optimum hole so that the LED doesn't slide against the body of the Mini Maglite (otherwise it gets caught to the surface and might twist the 24-gauge wire leads). Don't rush in assembling the Mini Maglite – take your sweet time doing it.

It's Ready!

Completed Conversion to LEDCompleted Conversion to LED

It was fun building this kit – even though I had to do it twice. My first attempt with SMT soldering did not go well but after some practice it came together. This will surely be a useful flashlight – I think it will provide you with a constant current drive, giving you a constant light output independent of the battery voltage. And, you won't need to carry that extra set of batteries as your Mini Maglite's life expectancy just increased!

How would you hack your own flashlight? Tell us on our community forum.
Jack Arcade earned his master's degree in Mechanical Engineering from Santa Clara University and works as a Product Marketing Engineer at Jameco Electronics. He specializes in the design and control of robots. Jack's interests include traveling, camping, trekking, river rafting, bungee jumping and mountain climbing.