Phone and Tablet Battery Charger (cheap and Rechargeable)




About: I am an engineer focused on recycled batteries, electric vehicles and renewable energy. I am always working on engineering projects I can’t stop.

This is a cheap and small mobile battery to charge your cell phone and table. It easily first in your pocket. It is rechargeable and can fully charge an I phone about 5 times between recharges.

I build this using

A USB car charger
Half a used laptop battery
Hot glue
Soldering iron
Small switch
Small box

Step 1: Building It

First buy a USB car charger. They are cheap I got mine for about $6.

Use a screw driver to pop open the plastic housing.

Find a box that the 3 batteries fit in snuggly. If you have a 3D printer printing a housing would work great.

Connect the 3 batteries in series to get 12 Volts total. I also used hot glue to glue the batteries together.

Solder the wires and switch together. The switch disconnects the USB board when not in use. I also soldered wire pieces before the switch so you can charge it with the switch off.

I glued the batteries in the box. I cut holes for the switch, USB plug and charge wires. I glued a piece of cardboard on the end to close the box.

I also added hot glue on the LED which lights up the clear glue.



    • Backyard Contest

      Backyard Contest
    • Classroom Science Contest

      Classroom Science Contest
    • Beauty Tips Contest

      Beauty Tips Contest

    4 Discussions


    here is my pack lol i run my hand held cb radio from it pcb is yet to arrive the pack in middle was in 1s70p config it is now in 3s23p for a total of 50 amp hours


    you really need the 3s protection circuit to kill power if one of the cells is flat charging 3 in series is very dodgy as it is easy to over charge one and under charge another and ideal a imax b6 balance charger even a copy one would be better then nothing bonus to one of these as well is you can check capacity of the cells