) made a great instructable (https://www.instructables.com/id/Modify-a-cheap-USB-charger-to-feed-an-iPod-iPhone/
) telling about how to charge apple devices such as ipod or the famous iphone. When I asked him to include the information here, he send me the following link where he got his information: http://www.ladyada.net/make/mintyboost/icharge.html
The solution is for the mysteries problem of non-charching devices is...
Sending exact voltages through the datalines. To get those 2 voltage dividers made of two resistors each are used. There are two ways to charge:
with full current (1000mA): 2.8 V on D- and 2.0 V on D+
with half current (500mA): 2.0 V on D- and 2.0 V on D+
Before you start to solder, try out the adapter with other devices to make sure everything works fine.
Because the space is very limited, you should try to get the smalest parts as possible; betwenn + and D- and D+ and - you could even solder a tiny SMD resistor. The values you need are shown in the pictures above. When you go an measure in the next step mind that you connected + and - with resistores (that means different results).I've never tried this so I can't say if it works!