Step 1: What you'll need
You'll also need a cell phone that takes a battery of 3-3.7 volts.
Step 2: The Battery Case
Use the needle nosed pliers to hold the wires while you strip a small amount of the jacket off of the wire. Then solder the wire onto each of the contacts on the case.
Step 3: Find the polarity of the battery and test your phone.
Step 4: Test It
Step 5: Put it together
BE SURE TO GET THE POLARITY RIGHT, you may want to put some hot glue over the contacts to prevent shorting.
(note, if the phone works, but the batteries are hot, you need to add another set in parallel, i had to)
Step 6: Your done+ more pix
WARNING: AFTER MAKING THIS MOD; DO NOT PLUG YOUR PHONE INTO THE CHARGER
I AM NOT RESPONSIBLE FOR ANY DAMAGE TO YOUR PHONE!