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Tail switch modification tutorial

Elyas

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Hello every one, this is a tutorial on how to modify your 18650 host to suit a 3v laser module. Its very easy and will take you around 5 minutes.
we know that a 18650 battery is 4.2v when fully charged, and some of the green laser modules are rated at 3V but they can still run on a 18650 battery, but they will get hot very quickly as the regulator transfers excess "voltage" into heat. to eliminate this problem, we can use a simple diode in series with the laser and there will be a voltage drop of 0.7v

Diode: there are many types of diode out there, in this tutorial we will be using a rectifier diode. which is black with a gray line on one side. (can be found in almost every electrical devices)

Voltage drop: i am not gonna go in details about electronics, but i will give a brief description, in a series circuit (components are attached one after the other) current is constant and voltage varies across each component. in parallel (components are connected parallel) voltage is constant and current is shared.

by using the concept of series circuit, we can minimize the amount of voltage going to the laser module by 0.7v which makes a lot of different.

I have done this tutorial on a SolarForce L2 as this is the only hosts that i currently have. but this mod can be done on almost any host.

In a flash light case is mostly positive, by opening the switch we can see that the positive side of the battery makes contact to the the spring on the tail switch, which is connected to the switch, when its on the current runs through the spring and the switch to the flash light's shell.

In this tutorial we are going to make a little changes to that, we are gonna add a diode between the spring and the switch. so current runs through the spring the diode and the switch then to the shell and there will be a 0.7v drop.

below are the pictures that illustrates it, sorry for the bad quality image and "tidy work"

the SolarForce L2


after taking the tail switch off we can find a washer type screw, unscrew that and you should find the following in it. from left to right: washer screw, plastic ring to avoid contact between the spring and the washer screw, switch, switch host, tail switch rubber and the switch host.



next what you wanna do is unsolder the switch from the circuit board, sorry i couldn't take photos of how it looked before the mod, but its very obvious. As i mentioned before, the spring is connected to the switch then the shell. I used a dremill to to get rid of the copper which runs from spring to the switch, then i soldered the diode to the board from the spring to to the switch. making sure i can solder the switch back to its original position. i also took some material off the plastic switch to allow it to sit flat on the diode terminal.


Solder the switch back to the board, and cut some material off the switch host to allow for a tight fit.



assemble it back together. And as expected the light is much dimmer, again sorry i forgot to take photo before the mod.



just when you thought its all over i got one more mod for the heat sink and the module. A lot of people have been complaining that module's driver board bends when they insert the battery. my suggestion is to shorten the spring on the module or use epoxy to secure it, like the image below.





Please leave a Positive rep, if you like any of these tutorials, thanks.
 

Elyas

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Thanks Billiam, hope it helped you out. PM me I you have any other issues wit you're laser :)
 




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