Phone Charger With a Smints Box




Nowadays having a phone is the most common thing.If you don't have one you can't survive in this time. You use it for nearly everything but, what happens when you need to charge it but you don't have a plug near to you?!!! Thats why they have created the powerbanks and the phone chargers.If you don't want to buy one or you just want to have some fun building it this instructable is for you.

I'll teach you how to build a very cheap and easy to build portable phone charger with a smints metal box.If you live in this century you HAVE TO build it.It will just take you 1 hour as much and you'll have fun.So what are you waiting for?Read the instuctable and start right now.

-Please vote me for the Epilog Contest because I if I had a laser cutter I could make many projects that I have in my "to do" list and it would help me a lot.So if you want more awesome instructables, vote me ;-)

Here's the instructable wich gave me the idea to make this one:

Step 1: Materials & Tools


A Smints metal box

A female usb

A 9v-5v voltage regulator

A 9 volts battery


Insulating tape

Soldering iron


Hot glue gun


Rotatory tool


Step 2: The Circuit L

Here you have some sketches of the circuit so you don't get confused.

Step 3: The Circuit Ll

Cut as many pieces of wire as you need and peel the end of the wires. Then put one wire around one pole of the 9v battery. Do the same with the other pole and with put some tape so they don´t move.Instead of doing this you could also use a 9v battery clip but I didn't have one.

Separate the legs of the regulator so when you solder them they don't stick to each other.Solder the positive wire of the battery to the left leg(input) of the regulator.Then solder the negative wire of the battery to the middle leg(GND).After that take another wire and solder one side to the right led(output)and the other side to the positive leg of the usb.Now take one more wire and solder one side to the GND and the other side to the negative leg of the usb.

If you have problems go to the previous step in wich there are some sketches of the circuit.

With the multimeter make sure the voltage that you have in the usb is of 5v.

Then with the insulating tape insulate the components.

Try it and make sure it works.

Step 4: The Box

Draw a rectangle where you want to connect the phone.With the drill make four holes in the corners and then with the dremel cut it out.Introduce all the circuit inside the box and glue the usb with the hot glue gun. I've decided to cover all the side with hot glue but that's up to you.

Step 5: Use It

Now you have your own portable phone charger.

Enjoy it :-)

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    20 Discussions

    Avik wadhwa

    3 years ago

    Loved it. I am voting for this. But please explain how it works

    1 reply
    Gomi no Sensei

    3 years ago

    Most smart phone batteries are 1500-3300mah.

    A 9V battery has 50-400mah and at 500mw load has less than 300mah capacity.

    You're also losing 30% of that 300mah thru the 7805 as heat.

    Just exactly HOW much does this remaining 210mah charge your phone ???

    Ref :


    Reply 3 years ago

    Not even once, this is reather a simple charger, for someone that is starting with eletronics, it doesn't have capacitors, a indicator led and a way to charge or even remove the battery.
    The 9v battery (ni-cd) shown has like 300mAh, meaning that in an ideal world, it provides 0,3A during one hour at 9v (i mean in an ideal world!). But, modern phones has Li-on batteries (search ni-cd vs li-on in google to know the difference) that can hold much more charge.
    The Samsung Galaxy S5 has a 2800mAh battery. So, assuming ideal environments, the S5 will charge like 10%. An Iphone 5s (Around 1600mAh i think) will charge a little less than 19% (Won't work in one, the circuit for an iphone is different, requires 2v on the other two usb terminals).

    Just to finish the thought, a usb port usually draws 500mAh, so, the total discharge of the battery will take like a little bit more than half an hour.


    3 years ago on Introduction

    LM 7805 will generate more heat than useful voltage to charge phone. You should rather go and find a step-up converter and step up 3.7 cell. They often have conversion efficiency around 80% so using cell same big as 9V battery you will get around 900 mAh than 300 from your 9v battery. Regulators like LM7805 are good for stabilising the voltage that oscillates around 5V

    2 replies

    Reply 3 years ago on Introduction

    And keep up good Work! I have LM7805 "charger" in my instructable as well so it is a good starting point to know what you can do better!

    Thanks! Very good and complete answer. Glad you understand it enough for such a complete and accurate answer. (I'm an electronics engineer with over 40 years of experience, so I can spot it pretty quick when someone is "blowing smoke".) :-)

    Since you're dealing with a battery for the input to the regulator, no need for capacitors--there's no AC ripple to smooth out.


    3 years ago

    ic will become super hot and where are the filter capacitors ? and heat sink ?

    1 reply

    Reply 3 years ago

    True about the capacitors, the IC could be held by a screw in the case itself (it's metal), just make a little hole and it's done!