Here is a project I have been working on for a couple of weeks. Its still evolving but its close.
It is a portable charger for phones or compatible devices with USB charging port and a port to charge the two 2600 Mah batteries. It uses an 7.5vdc AC adapter for charging the batteries. Inside is a USB step down board to regulate the voltage to 5vdc for the devices. It charges a phone with a 1700Mah battery in about 2 hrs. at .6 amps. The wall charger is the same at .6 amps.