Step 1: What's Needed
What you need for this is a USB (broken or not , just make sure it's long enough), you will also need the phone you want to charge.Im using a samsung SGH-T809(old phone, didn't have its proprietary charger). The last thing you need is something to plug the USB into, I recommended a laptop but a wall outlet will work fine.
Step 2: Step 1
Now cut the USB in half so that you have the USB , you can throw the other half away. I used scissors because I didn't have a wire stripper. Your gonna wanna strip the red and black wires, the green and white wires are not gonna be used.
Step 3: Step 2
Depending on what phone your using , the battery pins may be different . For me they were push down pins. Now your gonna wanna take the wire (red and black) , Match the pins with the wires(red with positive and black with negative). Once you figured out where the belong, bend the wire (metal part) onto the wire (this is what I did because mine has push down pins). Now take the wire and try to slide it under the pin (there should be a little space under the pins).
Step 4: Step 3
Now put the battery in, it should be a little hard to put in since the pins have something under them. Once it's in the wires won't move at all (or atleast that's what happened for me).
Step 5: Step 4
Plug it into your USB port that has power and your phone should light up or do something to indicate power, mine doesn't so I have to press the power button. It should turn on and there you go , you have a makeshift charger!