So i wanted to make a mini usb pass though but could not find a female mini usb port. So i set out to find the cheapest thing i could with a mini port, found a thing called digipower at radio shack for $12 thinking i could just use the mini female port. but wait there's a battery....... so i did some test and it has 5V coming out of the out side solders on the out going port steady even when charging. so a pass through and a battery. here is a link to the digipower thing i used Digipower Solutions JS1-V3 Jumpstart Instant Cell Phone Charger - JS1-V3 - Buy.com with just enuff room in the cap for a switch and a atty conection i set out this is what i got not to pretty but works like a champ. ( charging the battery to full now to see how long the thing will last when not plugged in.