Micro USB Lithium Charger for Cilindrical Lithium Baterry




About: I like making things, trying to utilize my hands and my brain. There is no limit!

I got a green laser from ebay, pretty cheap and it included one piece of 18650 Lithium battery, wall charger for the battery, caring box for the laser etc. This raised a question mark given the price and the number of objects I received.

In one day I wanted to charge my 18650 battery and after a while, I heard something popping, a sound from the wall charger. The magic smoke came out and the charger was not good anymore. I assumed that some sort of capacitor was blown given the smell and the smoke :)

I removed the screws and I found a blown capacitor. My initial thought was to scrap the charger. After a good sleep, I came back to better feelings: I can use the plastic housing of the charger to put inside a nice micro USB lithium charger PCBA.

More details about this micro USB charger you can find from Julian's video: New TP4056 Lithium Cell Charger Module with Battery Protection (this is from ebay - I picked one randomly: Micro USB 1A Lithium Battery Charger Module)

This is pretty straight forward project, follow the not-so-detailed steps.


-you re-purposed an object instead of creating more garbage

-this charger can accommodate various lithium size batteries

-you can charge lithium batteries wherever you have a micro USB connection (car, home, outdoors)

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Step 1: Open the Charger

Use a screw driver to open the charger (on mine were 5 Philips screws)

Step 2: Remove the Electronics of the Charger

Remove the electronic board (PCBA) of the charger, desolder the battery contacts from the electronic board and dispose the electronics board on a recycling bin for electronics

Step 3: Make a Rectangular Hole

Check where the micro USB charger PCB will sit inside the plastic housing and make a rectangular hole to match the micro USB connector of the PCB.

I used a red hot screw driver tip to drill that hole and a cutter to remove any burrs. You can do the same for the LEDs, it is not mandatory (you can see the LEDs through the plastic case).

Step 4: Solder Wires

Solder the wires to the micro USB charger and to the metal contacts for the battery. Pay attention to the polarity ("+" and "-").

Connect a micro USB cable to check that the charger is working.

Step 5: Secure Wires and Parts Inside

Now you have a plastic housing, secure the wires and the micro USB lithium charger inside with hot melt / hot glue.

Make sure that the spring is moving free inside.

Step 6: Enjoy Your Charger :)

Put the charger back, fasten the screws and use your new charger! (the blueish spot on the case is created by the LED from the charger)



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    8 Discussions


    2 years ago

    i think really all you would need is a silicon diode because if I remember the voltage drop typically is about .7 volts so with the diode you would have reverse polarity protection and the perfect charging voltage as usb provides 5 volts, so with the diode it should be 4.3 volts. Haven't tested this but it seems in theory all you would need to charge with usb is a diode and a cable :)

    1 reply

    Reply 2 years ago

    Thanks for your feedback, it may work what you are saying. You can provide the correct voltage using 5 volt USB and a regular diode and using the USB charger you should be able to give a certain amount of current. Also you need to keep an eye on a clock, divide battery capacity to the current provided by USB charger to see how much time is needed to let it charge. One I'll experiment this:)


    2 years ago

    If the charger blew up when you tried to use it my advise would be to assume the other parts had similar production values, and to look for lipo disposal methods. cheap chinese lipos from ebay are a no-no

    1 reply

    Reply 2 years ago

    Thanks for your feedback, I agree about lipos from ebay, you can pay a few dollars for a 6000 mAh :) I use recovered 18650 from laptop batteries. Regarding the electronics I used, that micro USB module may fail as well, but I trust it since I am using this for a while and on the other hand the voltage is lower.


    2 years ago

    Is there any overcharge and reverse polarity protection on that chinese charger - pcb?

    Or need i take care of that by myself?

    1 reply

    Reply 2 years ago

    Thank you for your feedback, I added an important-missing link - there is an youtube video and there you can find a good explanation on how this module work. Basically it will take care on the Lithium cell (single cell), it will charge it and will discharge it on the given specs of the Lithium.