iPhone DIY Powerbank

8*AA NiMH Battery 2800mah

Materials/Tools Needed
Car mobile usb charger
AA batery holder
AA batteries 8 pcs
Switch
Utility box ( i used telephony u box here)

Tools:
Soldering iron + lead
Glue stick
Scoring Blade ( for hole cutting )
Pencil
Masking tape(optional)
Electrical Tape(a must)

Step 1: Dismantling

Disassemble the Car mobile charger,and keep all the unnecessary parts for future projects.We only need the USB chip part.,plan where it would be placed inside the utility box,.making sure all other parts needed would fit in inside the u-box.Make a hole on a u-box for usb & switch.I put 0.5mm thick foam underneath the usb pcb,.to support it from bending & moving downward & up.Glue the USB port/chip using Glue gun to prevent it to be pushed or pulled upon insertion of usb cable

Step 2: Placements

Place all the necessary parts according to the size of u-box.,no need to soldered all the wire so you can rearrange it if necessay,making sure you can still close the u-box properly,.otherwise using the u box will be useless for portability.

Step 3: Soldering Wires

Series battery connections was applied here,just scrape the wire insulation,twist & connect to its corresponding place.then re check all the connections carefully to be safe,to avoid shorting the usb pcb chip components.If sure enough with the Series connections,load up all 8 AA batteries accordingly to the battery holder.Double check if you placed the batteries properly.Then Turn on the Switch,.if your Usb port Led lights up,.then you're good to go on soldering the wires now.

Step 4: Run Test

After soldering all the wire connections in series.,Turn on the switch,.if the led lights up,.its sure its working right,plug any device requiring 5v compatible with usb connection,i used 2nd gen ipod player,.& it worked as intended..it charges like on ac outlet.
Note:Dont forget to insulate open wire connections by covering it with electrical tape.To avoid unintentional shorting of the wires from bending.

Step 5: More Test

Run tests on devices if it will work in open/closed u-box..if it worked you are done!.
You have just built an affordable Powerbank,a bit bulky.(UBox = 2"depth x 2"height x 3.5"width)

Step 6: Result

It's quite complicated for others,but its not.
No complicated electronic schematic diagrams to analyze,.not much to assemble complicated electronic parts.Just the basics of soldering & wirings.And it's very cheap to make.
USB car charger only cost me 60 Php,
Battery holder 25Php/set x 4 total of 100 Php
Switch cost 20Php

It only cost in total of Php 180.00 (1$= Php40++) on the day i bought on electronic store.

AA Battery cost excluded = Php 30.00 for 8 pcs

All other parts are only spare that i kept.It was really a big savings on my side, instead of buying without the Fun of creating.!

Facts about AA Batteries
•Primary (non-rechargeable) zinc–carbon (dry cell) AA batteries have around 400–900 milliamp-hours capacity
•.Zinc–carbon batteries are usually marketed as "general purpose" batteries. Zinc-chloride batteries store around 1000 to 1500 mAh are often sold as "heavy duty" or "super heavy duty".
•Alkaline batteries from 1700 mAh to 3000 mAh cost more than zinc-chloride batteries, but last proportionally longer.
http://en.m.wikipedia.org/wiki/AA_battery

• i used ordinary AA Battery for this project and based on this facts it would range this project on specs of 500 mah ,.actual measured on app installed....,meanwhile using rechargable AA batterries would be a great added savings on user.,+++