External battery pack

I own a Javoedge external battery pack that I used to charge iPods, a PSP and a DS. However, I tried it with the iPhone and it does not seem to charge.

JAVOedge claims on its website that it does work with the iPhone. Emailed them and they said I need a different cable other than the one that came with the iPhone.

Is this possible? Does the iPhone cable somehow regulates voltage? The battery outputs 5.5V

Thanks for any thoughts!

 

This external battery does work with the iPhone:

http://www.javoedge.com/reflexeshop/productCatalog/getProduct.do?poid=1595&pbmId=13195

For some reason you have to use their cable and tips. The iPhone or iPod cables don't work. Tested them myself after much skepticism.