Why won't this battery charge an Iphone?

I have an Iphone 4 and I'm trying to make a portable solar charger. I just got a 4.8 volt 1800mah rechargeable battery. When I connected the usb to an old Ipod I have the battery was able to charge to Ipod. But, when I connected to to my Iphone nothing happens. All I did was connect the battery to a usb female which connected to the ipod. Why won't it charge my phone?

Added (1). To sultan: I'm not sure what you mean by charge the usb. Right now my set up is Ipod to its normal white usb wire to a female input that connects to the plus and minus of my battery. Only the ipod works in this set up but now the iphone.

Is the charger adapter built in your do you put your own ones? Change the usb you connect the iPod to the charger.

  • Why won't the battery charge an Iphone? I have an Iphone 4 and I'm trying to make a portable solar charger. I just got a 4.8 volt 1800mah rechargeable battery. When I connected the usb to an old Ipod I have the battery was able to charge to Ipod. But, when I connected to to my Iphone nothing happens. All I did was connect the battery to a usb female which connected to the ipod. Why won't it charge my iphone?
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